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  • 1.
    Akkarasamiyo, Sunisa
    et al.
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Sawadjoon, Supaporn
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Samec, Joseph S. M.
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Tsuji-Trost Reaction of Non-Derivatized Allylic Alcohols2018Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, nr 14, s. 3488-3498Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Palladium-catalyzed allylic substitution of non-derivatized enantioenriched allylic alcohols with a variety of uncharged N-, S-, C- and O-centered nucleophiles using a bidentate BiPhePhos ligand is described. A remarkable effect of the counter ion (X) of the XPd[kappa(2)-BiPhePhos][kappa(3)-C3H5] was observed. When ClPd[kappa(2)-BiPhePhos][eta(3)-C3H5] (complexI) was used as catalyst, non-reproducible results were obtained. Study of the complex by X-ray crystallography, (PNMR)-P-31 spectroscopy, and ESI-MS showed that a decomposition occurred where one of the phosphite ligands was oxidized to the corresponding phosphate, generating ClPd[kappa(1)-BiPhePhosphite-phosphate][eta(3)-C3H5] species (complexII). When the chloride was exchanged to the weaker coordinating OTf- counter ion the more stable Pd[kappa(2)-BiPhePhos][eta(3)-C3H5](+)+[OTf] (-) (complexIII) was formed. ComplexIII performed better and gave higher enantiospecificities in the substitution reactions. ComplexIII was evaluated in Tsuji-Trost reactions of stereogenic non-derivatized allylic alcohols. The desired products were obtained in good to excellent yields (71-98%) and enantiospecificities (73-99%) for both inter- and intramolecular substitution reactions with only water generated as a by-product. The methodology was applied to key steps in total synthesis of (S)-cuspareine and (+)-lentiginosine. A reaction mechanism involving a palladium hydride as a key intermediate in the activation of the hydroxyl group is proposed in the overall transformation.

  • 2.
    Arkhypchuk, Anna I.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Borbas, K. Eszter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Synthesis and Characterization of Ferrocenyl Chlorins, 1,1'-Ferrocene-Linked Chlorin Dimers, and their BODIPY Analogues2017Ingår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 56, nr 5, s. 3044-3054Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present the synthesis and characterization of meso-ferrocenyl-substituted hydroporphyrins (chlorins) and 1,1' -linked chlorin dimers. The dipyrromethane chlorin precursors were also transformed into Fc-substituted BODIPYs and 1,1'-ferrocenyl-linked BODIPY dimers. The chlorin dimers were studied by 1D and 2D NMR experiments and DFT calculations, which showed that their solution structures were dependent on the central metal. Monomeric and dimeric Ni(II) chlorins had similar H-1 NMR spectra. Monomeric and dimeric free base, Zn(II), and Pd(II) chlorins, on the other hand, showed significantly more different spectra. The eclipsed conformer of the free base chlorin dimer was calculated to be energetically more favored than the open form. The chlorin and BODIPY fluorescence emissions were quenched in the Fcsubstituted compounds; these could be recovered by oxidation of the Fe(II) center. Cyclic voltammetry showed up to five oxidation waves for the free base chlorin dimer, which suggests that the macrocycles were not behaving independently of each other.

  • 3.
    Arkhypchuk, Anna I.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Kovacs, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Borbas, K. Eszter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Isolation and Characterization of a Monoprotonated Hydroporphyrin2018Ingår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, nr 48, s. 7051-7056Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A simple protocol for the controlled preparation of mono- and diprotonated hydroporphyrins (chlorins) is presented. The chlorins carried 10-aryl groups with electron-neutral (phenyl), electron-donating (p-OMe-C6H4) or electron-withdrawing (pentafluorophenyl) substituents. The protonation reactions were readily followed by UV/Vis absorption spectroscopy, enabling the determination of the first (4.8-5.3) and second pK(a)'s (1.7-0.5). Both mono- and diprotonated species were fully characterized by H-1 NMR spectroscopy, which, in combination with theoretical studies, showed that these macrocycles were significantly distorted in solution. A 10-phenyl-substituted monoprotonated chlorin was characterized by X-ray crystallography. This is the first structurally characterized hydroporphyrin monocation, and the first crystal structure of a sterically unencumbered singly protonated tetrapyrrole. The photostabilities of the mono- and diprotonated 10-phenylchlorins were measured upon irradiation into their Soret bands; protonation yielded increased photostabilities.

  • 4.
    Arkhypchuk, Anna I.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Mihali, Viorica Alina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Ehlers, Andreas
    Lammertsma, Koop
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Oxaphospholes and Bisphospholes from Phosphinophosphonates and alpha,beta-Unsaturated Ketones2013Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, nr 41, s. 13692-13704Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The reaction of a {W(CO)(5)}-stabilized phosphinophosphonate 1, (CO)(5)WPH(Ph)P(O)(OEt)(2), with ethynyl- (2a-f) and diethynylketones (7-11, 18, and 19) in the presence of lithium diisopropylamide (LDA) is examined. Lithiated 1 undergoes nucleophilic attack in the Michael position of the acetylenic ketones, as long as this position is not sterically encumbered by bulky (iPr)(3)Si substituents. Reaction of all other monoacetylenic ketones with lithiated 1 results in the formation of 2,5-dihydro-1,2-oxaphospholes 3 and 4. When diacetylenic ketones are employed in the reaction, two very different product types can be isolated. If at least one (Me)(3)Si or (Et)(3)Si acetylene terminus is present, as in 7, 8, and 19, an anionic oxaphosphole intermediate can react further with a second equivalent of ketone to give cumulene-decorated oxaphospholes 14, 15, 24, and 25. Diacetylenic ketones 10 and 11, with two aromatic acetylene substituents, react with lithitated 1 to form exclusively ethenyl-bridged bisphospholes 16 and 17. Mechanisms that rationalize the formation of all heterocycles are presented and are supported by DFT calculations. Computational studies suggest that thermodynamic, as well as kinetic, considerations dictate the observed reactivity. The calculated reaction pathways reveal a number of almost isoenergetic intermediates that follow after ring opening of the initially formed oxadiphosphetane. Bisphosphole formation through a carbene intermediate G is greatly favored in the presence of phenyl substituents, whereas the formation of cumulene-decorated oxaphospholes is more exothermic for the trimethylsilyl-containing substrates. The pathway to the latter compounds contains a 1,3-shift of the group that stems from the acetylene terminus of the ketone substrates. For silyl substituents, the 1,3-shift proceeds along a smooth potential energy surface through a transition state that is characterized by a pentacoordinated silicon center. In contrast, a high-lying transition state TS(E-F)(R=Ph) of 37kcalmol(-1) is found when the substituent is a phenyl group, thus explaining the experimental observation that aryl-terminated diethynylketones 10 and 11 exclusively form bisphospholes 16 and 17.

  • 5.
    Arkhypchuk, Anna I.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Tuning the Optical Properties of 1,1'-Biphospholes by Chemical Alterations of the P-P Bridge2014Ingår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2014, nr 10, s. 1760-1766Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    2,5-Di(1-naphthyl)-1-phenylphosphole (2) was prepared from phenylphosphine and dinaphthylbutadiyne in 70% yield, and oxidized to its oxide 3. Treatment of 2 with a solution of potassium naphthalide results in selective formation of phospholide anion 4, which can be oxidized with iodine to afford biphosphole 5. The crystal structure of 5 exhibits an unusual s-trans conformation across the P-P bridge that is most stabilized by - stacking of the naphthyl substituents. Biphosphole 5 can be oxidized to its mono-oxidized 6 and dioxide 7. Generally, all phosphole oxidations lead to decreased pyramidalization of the P centres and, consequently, to significantly redshifted lowest-energy absorption maxima. Mono-oxidized biphosphole 6, which consists of an ordinary phosphole and an electron-deficient oxidized phosphole, features a unique low-energy optical transition (shoulder at 430 nm), which is tentatively assigned to a charge-transfer transition. The UV/Vis spectrum of dioxide 7 lacks this transition. At the same time, the emission maximum of 7 is bathochromically shifted by 80 nm relative to that of 5.

  • 6.
    Arkhypchuk, Anna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Svyaschenko, Yurii
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Mechanism of the Phospha-Wittig-Horner Reaction2013Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 52, nr 25, s. 6484-6487Artikel i tidskrift (Refereegranskat)
  • 7.
    Blunder, Martina
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap, Funktionell farmakologi. Graz Univ, Dept Pharmacognosy, Inst Pharmaceut Sci, Univ Pl 4, A-8010 Graz, Austria.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik. Graz Univ, Dept Pharmaceut Chem, Inst Pharmaceut Sci, Univ Pl 1, A-8010 Graz, Austria.
    Bauer, Rudolf
    Graz Univ, Dept Pharmacognosy, Inst Pharmaceut Sci, Univ Pl 4, A-8010 Graz, Austria.
    Bucar, Franz
    Graz Univ, Dept Pharmacognosy, Inst Pharmaceut Sci, Univ Pl 4, A-8010 Graz, Austria.
    Kunert, Olaf
    Graz Univ, Dept Pharmaceut Chem, Inst Pharmaceut Sci, Univ Pl 1, A-8010 Graz, Austria.
    Efficient identification of flavones, flavanones and their glycosides in routine analysis via off-line combination of sensitive NMR and HPLC experiments2017Ingår i: Food Chemistry, ISSN 0308-8146, E-ISSN 1873-7072, Vol. 218, s. 600-609Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a standardized, straightforward and efficient approach applicable in routine analysis of flavonoids combining sensitive NMR and HPLC experiments. The determination of the relative configuration of sugar moieties usually requires the acquisition of 13C NMR shift values. We use a combination of HPLC and sensitive NMR experiments (1D-proton, 2D-HSQC) for the unique identification of known flavones, flavanones, flavonols and their glycosides. Owing to their broad range of polarity, we developed HPLC and UHPLC methods (H2O/MeOH/MeCN/HCOOH) which we applied and validated by analyzing 46 common flavones and flavanones and exemplified for four plant extracts. A searchable data base is provided with full data comprising complete proton and carbon resonance assignments, expansions of HSQC-spectra, HPLC parameters (retention time, relative retention factor), UV/Vis and mass spectral data of all compounds, which enables a rapid identification and routine analysis of flavones and flavanones from plant extracts and other products in nutrition and food chemistry.

  • 8.
    Bunrit, Anon
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Dahlstrand, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Olsson, Sandra K.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Srifa, Pemikar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Huang, Genping
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Sjöberg, Per J. R.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Biswas, Srijit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Himo, Fahmi
    Samec, Joseph S. M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Bronsted Acid-Catalyzed Intramolecular Nucleophilic Substitution of the Hydroxyl Group in Stereogenic Alcohols with Chirality Transfer2015Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 137, nr 14, s. 4646-4649Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hydroxyl group of enantioenriched benzyl, propargyl, allyl, and alkyl alcohols has been intramolecularly displaced by uncharged O-, N-, and S-centered nucleophiles to yield enantioenriched tetrahydrofuran, pyrrolidine, and tetrahydrothiophene derivatives with phosphinic acid catalysis. The five-membered heterocyclic products are generated in good to excellent yields, with high degree of chirality transfer, and water as the only side-product. Racemization experiments show that phosphinic acid does not promote S(N)1 reactivity. Density functional theory calculations corroborate a reaction pathway where the phosphinic acid operates as a bifunctional catalyst in the intramolecular substitution reaction. In this mechanism, the acidic proton of the phosphinic acid protonates the hydroxyl group, enhancing the leaving group ability. Simultaneously, the oxo group of phosphinic acid operates as a base abstracting the nucleophilic proton and thus enhancing the nucleophilicity. This reaction will open up new atom efficient techniques that enable alcohols to be used as nucleofuges in substitution reactions in the future.

  • 9.
    Cadu, Alban
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Watile, Rahul
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Biswas, Srijit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Sjöberg, Per J
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Samec, Joseph
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions2014Ingår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 16, nr 21, s. 5556-5559Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An atom-efficient synthesis of keto thioethers was devised via tandem gold/palladium catalysis. The reaction proceeds through a regioselective thiol attack at the β-position of the alcohol, followed by an alkyl, aryl, or benzyl 1,2-shift. Both acyclic and cyclic systems were studied, in the latter case leading to the ring expansion of cyclic substrates.

  • 10.
    Calard, Francois
    et al.
    Ecole Natl Super Chim Montpellier, Inst Charles Gerhardt , Architectures Mol & Mat Nanostruct, Montpellier, France..
    Wani, Ishtiaq Hassan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Hayat, Aqib
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jarrosson, Thibaut
    Ecole Natl Super Chim Montpellier, Inst Charles Gerhardt Montpellier, Architectures Mol & Mat Nanostruct, Montpellier, France..
    Lere-Porte, Jean-Pierre
    Ecole Natl Super Chim Montpellier, Inst Charles Gerhardt Montpellier, Architectures Mol & Mat Nanostruct, Montpellier, France..
    Jafri, S. Hassan M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap. Mirpur Univ Sci & Technol, Dept Elect Engn, Azad Kashmir, Pakistan..
    Serein-Spirau, Francoise
    Ecole Natl Super Chim Montpellier, Inst Charles Gerhardt Montpellier, Architectures Mol & Mat Nanostruct, UMR CNRS 5253, Montpellier, France..
    Leifer, Klaus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Designing sterically demanding thiolate coated AuNPs for electrical characterization of BPDT in a NP-molecule-nanoelectrode platform2017Ingår i: MOLECULAR SYSTEMS DESIGN & ENGINEERING, ISSN 2058-9689, Vol. 2, nr 2, s. 133-139Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Molecular electronics with single or few molecules requires a stable metal-molecule nanojunction platform. Herein, we report the design and synthesis of gold nanoparticles coated with sterically demanding thiol ligands that are essential to fabricate a versatile and stable nanoelectrode-molecule-nanoparticle platform suitable for electrical characterization of small organic molecules. By combining.-tetraphenylmethane ether functionalized alkyl thioacetate and alkyl thiols, we prepared highly stable gold nanoparticles in a one-phase reaction providing simple and efficient purification. This robust preparation gives highly pure nanoparticles in very high yields (up to 90%) with long-time shelf stability. The synthesis in this work has superior reproducibility compared to previous synthesis processes that are currently being used for such molecular electronics platforms. Electron microscopy confirms the formation of uniform and small nanoparticles in the range of 5 to 7 nm. These nanoparticles with different ligand surface coverages were placed in a 20 nm nanoelectrode setup using dielectrophoretic forces. This setup was utilized to characterize the conductivity of the molecular wire 4,4'-biphenyldithiol introduced via ligand placeexchange under ambient conditions.

  • 11.
    Das, Biswanath
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Thapper, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Iron Pentapyridyl Complexes as Molecular WaterOxidation Catalysts: Strong Influence of a Chloride Ligandand pH in Altering the Mechanism2016Ingår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 10, s. 1178-1186Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of molecular water oxidation catalysts basedon earth-abundant, non-noble metals is essential for artificial photosynthesis research. Iron, which is the most abundant transition metal in the earth's crust, is a prospective candidate for this purpose. Herein, we report two iron complexes based on the polypyridyl ligand Py5OH (Py5OH=pyridine-2,6-diylbis[di(pyridin-2-yl)methanol]) that can catalyse water oxidation to produce O2 in RuIII-induced (at pH 8, highest turnover number (TON)=26.5; turnover frequency (TOF)=2.2 s-1), CeIV-induced(at pH 1.5 highest TON=16; TOF=0.75 s-1) and photo-induced(at pH 8, highest TON=43.5; TOF=0.6 s-1) reactions. A chloride ligand in one of the iron complexes is shown to affect the activity strongly, improve stability and, thereby, the performance at pH 8 but it inhibits oxygen evolution at pH 1.5. The observations are consistent with a change in mechanism for catalytic water oxidation with the Fe(Py5OH) complexes between acidic (CeIV) and near-neutral pH (RuIII).

  • 12.
    Das, Biswanath
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Thapper, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Water oxidation catalysed by a mononuclear CoII polypyridine complex; possible reaction intermediates and the role of the chloride ligand2015Ingår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, nr 66, s. 13074-13077Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A mononuclear cobalt(II) complex as a homogeneous molecular catalyst for photochemically, electrochemically and chemically induced oxygen evolution reactions is presented. Experimental evidence points towards the presence of a chloride ligand at the cobalt centre throughout the catalytic cycle, and the temporary detachment of a pyridine ligand to open a coordination site for substrate binding.

  • 13.
    Das, Biswanath
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Thapper, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Water oxidation catalyzed by mononuclear iron and cobalt polypyridine complexes2017Ingår i: Journal of Biological Inorganic Chemistry, ISSN 0949-8257, E-ISSN 1432-1327, Vol. 22, nr Supplement: 1, s. S259-S259Artikel i tidskrift (Övrigt vetenskapligt)
  • 14.
    Demory, Emilien
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Devaraj, Karthik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC. Uppsala Univ, Dept Chem BMC, S-75123 Uppsala, Sweden..
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Gates, Paul J.
    Univ Bristol, Sch Chem, Bristol BS8 1TS, Avon, England..
    Pilarski, Lukasz T.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Boryl (Hetero)aryne Precursors as Versatile Arylation Reagents: Synthesis through C-H Activation and Orthogonal Reactivity2015Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 54, nr 40, s. 11765-11769Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    (Pinacolato)boryl ortho-silyl(hetero)aryl triflates are presented as a new class of building blocks for arylation. They demonstrate unique versatility by delivering boronate or (hetero)aryne reactivity chemoselectively in a broad range of transformations. This approach enables the unprecedented postfunctionalization of fluoride-activated (hetero)aryne precursors, for example, as substrates in transition-metal catalysis, and offers valuable new possibilities for aryl boronate postfunctionalization without the use of specialized protecting groups.

  • 15.
    Devaraj, Karthik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Organisk kemi.
    Ingner, Fredric
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Organisk kemi.
    Sollert, Carina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Organisk kemi.
    Gates, Paul J.
    Univ Bristol, Sch Chem, Cantocks Close, Bristol BS8 1TS, Avon, England.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Syntetisk molekylär kemi.
    Pilarski, Lukasz T.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Organisk kemi.
    Arynes and Their Precursors from Arylboronic Acids via Catalytic C-H Silylation2019Ingår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 84, nr 9, s. 5863-5871Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new, operationally simple approach is presented to access arynes and their fluoride-activated precursors based on Ru-catalyzed C-H silylation of arylboronates. Chromatographic purification may be deferred until after aryne capture, rendering the arylboronates de facto precursors. Access to various new arynes and their derivatives is demonstrated, including, for the first time, those based on a 2,3-carbazolyne and 2,3-fluorenyne core, which pave the way for novel derivatizations of motifs relevant to materials chemistry.

  • 16.
    El Nahhas, Amal
    et al.
    Lund Univ, Dept Chem Phys, Lund, Sweden..
    Shameem, Muhammad Anwar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Chabera, Pavel
    Lund Univ, Dept Chem Phys, Lund, Sweden..
    Uhlig, Jens
    Lund Univ, Dept Chem Phys, Lund, Sweden..
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Synthesis and Characterization of Cyclopentadithiophene Heterofulvenes: Design Tools for Light-Activated Processes2017Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, nr 24, s. 5673-5677Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of new materials for solar-to-energy conversion should consider stability, ease of fabrication, and beneficial photophysical properties. In this context, a set of novel -conjugated building blocks, with phospha- and arsaalkenes possessing a unique dithienyl annulated heterofulvenoid core, have been prepared as air- and moisture-stable sensitizers. These compounds unify electron-donor and -acceptor moieties, making them potential candidates for light-harvesting applications. Optical characterization of these systems was performed by steady-state and time-resolved absorption spectroscopy, supported by time-dependent DFT calculations. Tuning of the optical properties of these systems can be achieved by varying the pnictogen element at the bridgehead position, giving a bathochromic shift of approximate to 40nm and coordinating the phosphaalkene towards gold Au-I centers. The latter results in a approximate to 2000-fold extension of the approximate to 10ps lifetime of uncoordinated systems well into the ns regime.

  • 17.
    Esfandiarfard, Keyhan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Arkhypchuk, Anna I.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Synthesis of the first metal-free phosphanylphosphonate and its use in the "phospha-Wittig-Horner" reaction2016Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, nr 5, s. 2201-2207Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis of the first phophanylphosphonate, Mes*PH-PO(OEt)(2) (2-H), in which the P(III) centre is not coordinated by a M(CO)(5) (M = W, Mo, Cr) fragment is reported. The title compound reacts with LDA under the formation of 2-Li which is best described as the enolate form with a high double bond character between the two phosphorus centres. 2-Li is shown to engage in the phospha-Wittig-Horner reaction and converts aldehydes into phosphaalkenes that are metal-free and thus available for future manipulations at the phophorus lone pair. Using a selection of aldehydes with aliphatic, aromatic or vinylic substituents as substrates, phosphaalkene formation proceeds in high yields and high E-selectivity. The selectivity is however compromised during purification on standard silica which was found to promote E/Z isomerization.

  • 18.
    Esfandiarfard, Keyhan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ott, Sascha
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Synthesis of 2,6-Dimesitylphenyl-C,C-dibromophosphaalkene2015Ingår i: Phosphorus Sulfur and Silicon and the Related Elements, ISSN 1042-6507, E-ISSN 1563-5325, Vol. 190, nr 5-6, s. 816-820Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A facile one-pot transformation of Dmp-I to Dmp-P=CBr2 (Dmp = 2,6-dimesitylphenyl), a valuable precursor for other unsaturated phosphorus compounds, is described. VT-1H-NMR experiments reveal a hindered rotation of the m-terphenyl structure with a rotational barrier of approx. 14 kcal/mol. Bromination of Dmp-I gives selective substitution of all aromatic protons of the mesityl substituents.

  • 19.
    Fuchs, Michael
    et al.
    Karl-FranzensUniversity Graz.
    Schober, Markus
    Karl-FranzensUniversity Graz.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Faber, Kurt
    Karl-Franzens University Graz.
    Asymmetric Synthesis of β-Substituted α-Methylenebutyro- lactones via TRIP-Catalyzed Allylation: Mechanistic Studies and Application to the Synthesis of (S)-(−)-Hydroxymatairesinol2013Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 355, nr 13, s. 2499-2505Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Asymmetric allylation of (hetero)aromatic aldehydes by a zinc(II)-allylbutyrolactone species catalyzed by a chiral BINOL-type phosphoric acid gave β-substituted α-methylenebutyrolactones in 68 to >99% ee and 52–91% isolated yield. DFT studies on the intermediate Zn2+-complex – crucial for chiral induction – suggest a six-membered ring intermediate, which allows the phosphoric acid moiety to activate the aldehyde. The methodology was applied to the synthesis of the antitumour natural product (S)-(−)-hydroxymatairesinol.

  • 20.
    Green, Joshua P.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Gupta, Arvind Kumar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Effect of Arsenic Coordination State on the Structure, Aromaticity, and Optical Properties of Dithieno[3,2-b:2 ',3 '-d]arsoles2019Ingår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, nr 11-12, s. 1539-1543Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A silylated derivative of 4-phenyl-dithieno[3,2-b:2 ',3 '-d]arsole (DTAs) was synthesized, and the effect of coordinating of DTAs compounds to Pd on their structural and optical properties was investigated. Coordination of the As to Pd was found to increase the structural aromaticity of the ring system as measured by the harmonic oscillator measure of heterocyclic electron delocalization (HOMHED), and the pyramidalization of the As atoms was also found to show a good correlation with the HOMHED values. However, coordination had a more subtle impact on the optical properties than seen for phosphorus-containing analogues as the metal-ligand interactions were weaker.

  • 21.
    Green, Joshua P.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Syntetisk molekylär kemi.
    Wells, Jordann A. L.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Syntetisk molekylär kemi.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Syntetisk molekylär kemi.
    Heavier pnictogens - treasures for optical electronic and reactivity tuning2019Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 48, nr 14, s. 4460-4466Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    We highlight recent advances in organopnictogen chemistry contrasting the properties of lighter and heavier pnictogens. Exploring new bonding situations, discovering unprecedented reactivities and producing fascinating opto-electronic materials are some of the most prominent directions of current organopnicogen research. Expanding the chemical toolbox towards the heavier group 15 elements will continue to create new opportunities to tailor molecular properties for small molecule activation/reactivity and materials applications alike. This frontier article illustrates the elemental substitution approach in selected literature examples.

  • 22.
    Gudat, Dietrich
    et al.
    Univ Stuttgart, Inst Anorgan Chem, Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Slootweg, J. Chris
    Univ Amsterdam, Vant Hoff Inst Mol Sci, Sci Pk 904, NL-1090 GD Amsterdam, Netherlands.
    Streubel, Rainer
    Univ Bonn, Inst Inorgan Chem, Gerhard Domagk Str 1, D-53121 Bonn, Germany.
    Phosphorus Special Issue in Honor of Koop Lammertsma and Edgar Niecke2019Ingår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, nr 11-12, s. 1437-1439Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Guest Editors Dietrich Gudat, Andreas Orthaber, Chris Slootweg, and Rainer Streubel report the increasing importance of phosphorus chemistry in Europe and beyond, summarizing the contributions in this special issue in honor of the 70th and 80th birthdays of Professors Koop Lammertsma and Edgar Niecke.

  • 23.
    Gupta, Arvind Kumar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Akkarasamiyo, Sunisa
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Rich Coordination Chemistry of pi-Acceptor Dibenzoarsole Ligands2017Ingår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 56, nr 8, s. 4504-4511Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of dibenzoarsole (also known as 9-arsafluorene) derivatives have been prepared, and their coordination chemistry has been investigated. The different ligand topology and the arsenic substituents govern the reactivity of the ligands. We report various crystal structures of palladium and platinum complexes derived from this family of ligands. The biphenyl backbone of the bridged bidentate ligands allows very flexible coordination. We have also studied the application of an allylic Pd complex in nucleophilic substitution reactions, revealing that the benzoarsole substituent is susceptible to metal insertion.

  • 24.
    Gupta, Arvind Kumar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Alkynyl Coinage Metal Clusters and Complexes-Syntheses, Structures, and Strategies2018Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, nr 30, s. 7536-+Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this Concept we discuss how the chemistry of coinage metal complexes based on alkynyl ligands has developed over the past decades. The rich coordination of alkynyl, that exhibit both (1) (end-on) and (2) (side on) modes, includes non-bridged systems, as well as bridging of up to four (or six) metal centres. Resulting metal clusters often exhibit highly regular structures and typical coordination motifs forming fascinating assemblies exploiting this versatile coordination. Metallophilic interactions are often an important driving force for the formation of large clusters. In addition, the use of co-ligands as well the possibility to encapsulate counter ions greatly increases the chemical and structural diversity. Herein we attempt to summarize and highlight design principles towards multinuclear homo and hetero-bi-metallic coinage metal clusters of alkynyl ligands.

  • 25.
    Karnahl, Michael
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Tschierlei, Stefanie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Nagarajan, Loganathan
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Structural and spectroscopic characterization of tetranuclear iron complexes containing a (P2N2Ph)-N-R bridge2012Ingår i: Journal of coordination chemistry (Print), ISSN 0095-8972, E-ISSN 1029-0389, Vol. 65, nr 15, s. 2713-2723Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A pair of tetranuclear iron complexes consisting of two Fe-2(Cl(2)bdt)(CO)(5) subunits (Cl(2)bdt = 3,6-dicholorobenzene-1,2-dithiolate) bridged by different cyclic 1,5-diaza-3,7-diphosphacyclooctane (P2N2) ligands were prepared and structurally characterized. In the solid state, the P2N2 ligands adopt a boat conformation, which results in rather short distances between the two Fe-2(Cl(2)bdt)(CO)(5) clusters that promotes electronic communication across the diphosphine ligand.

  • 26.
    Kovacs, Daniel
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Kiraev, Salauat
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Borbas, K. Eszter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Highly emissive Eu- and Tb-emitting bioconjugatable complexes of octa- and nonadentate macrocyclic ligandsManuskript (preprint) (Övrigt vetenskapligt)
  • 27.
    Kovacs, Daniel
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Phipps, Dulcie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Borbas, K. Eszter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Highly luminescent lanthanide complexes sensitised by tertiary amide-linked carbostyril antennae2018Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, nr 31, s. 10702-10714Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carbostyrils are among the most widely used sensitising antennae for luminescent lanthanides; they afford bright complexes with Eu and Tb, and can also sensitise the emissions of the less commonly used Sm, Dy, Yb and Nd. Systematic studies on the effect of structural variations on the photophysical properties and lanthanide sensitising abilities of carbostyrils can therefore have a large impact. We replaced the secondary amide linker that connects the metal binding site to the antenna with a carboxymethyl-substituted tertiary amide. Eight Tb and Eu complexes were prepared. All had higher lanthanide luminescence quantum yields (phi(Ln)) than their secondary amide analogues; three Tb emitters had phi(Tb) > 40%. Eu complexes had phi(Eu) up to 11.6%. The antenna singlet and triplet excited states are slightly shifted, while the metal coordination sphere is unchanged by the introduction of the carboxymethyl group.

  • 28.
    Liu, Tianfei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Guo, Meiyuan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Teoretisk kemi.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Lomoth, Reiner
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Lundberg, Marcus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Teoretisk kemi.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Hammarström, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Accelerating proton-coupled electron transfer of metal hydrides in catalyst model reactions2018Ingår i: Nature Chemistry, ISSN 1755-4330, E-ISSN 1755-4349, Vol. 10, nr 8, s. 881-887Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Metal hydrides are key intermediates in catalytic proton reduction and dihydrogen oxidation. There is currently much interest in appending proton relays near the metal centre to accelerate catalysis by proton-coupled electron transfer (PCET). However, the elementary PCET steps and the role of the proton relays are still poorly understood, and direct kinetic studies of these processes are scarce. Here, we report a series of tungsten hydride complexes as proxy catalysts, with covalently attached pyridyl groups as proton acceptors. The rate of their PCET reaction with external oxidants is increased by several orders of magnitude compared to that of the analogous systems with external pyridine on account of facilitated proton transfer. Moreover, the mechanism of the PCET reaction is altered by the appended bases. A unique feature is that the reaction can be tuned to follow three distinct PCET mechanisms-electron-first, proton-first or a concerted reaction-with very different sensitivities to oxidant and base strength. Such knowledge is crucial for rational improvements of solar fuel catalysts.

  • 29.
    Löfås, Henrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Jahn, Burkhard O.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Rouf, Alvi M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Grigoriev, Anton
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ottosson, Henrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    New Class of Molecular Conductance Switches Based on the [1,3]-Silyl Migration from Silanes to Silenes2013Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, nr 21, s. 10909-10918Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Based on first principles density functional theory calculations we propose a new molecularphotoswitch which exploits a photochemical [1,3]-silyl(germyl) shift leading from a silane to asilene (a Si=C double bonded compound). The silanes investigated herein act as the OFF state,with tetrahedral saturated silicon atoms disrupting the conjugation through the molecules. Thesilenes, on the other hand, have conjugated paths spanning over the complete molecules, andthus act as the ON state. We calculate ON/OFF conductance ratios in the range of 10 - 50at a voltage of +1 V. In the low bias regime the ON/OFF ratio increases to a range of 200 -1150. The reverse reaction could be triggered thermally or photolytically, with the silenebeing slightly higher in relative energy than the silane. The calculated activation barriers forthe thermal back-rearrangement of the migrating group can be tuned, and are in the range 108 -171 kJ/mol for the switches examined herein. The first principles calculations together witha simple one-level model shows that the high ON/OFF ratio in the molecule assembled in asolid state device is due to changes in the energy position of the frontier molecular orbitalscompared to the Fermi energy of the electrodes, in combination with an increased effectivecoupling between the molecule and the electrodes for the ON state.

  • 30.
    Morales Salazar, Daniel
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Gupta, Arvind Kumar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Reactivity studies of an imine-functionalised phosphaalkene; unusual electrostatic and supramolecular stabilisation of a σ2λ3-phosphorus motif via hydrogen bonding2018Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, s. 10404-10409Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A PC heavy-alkene analogue that is unreactive towards the addition of strong acids on its double-bond is presented; instead, a strategically located imine nitrogen on the periphery forms protonated adducts displaying hydrogen bonding interactions. These materials are significantly more stable than the parent species, demonstrating an unprecedented approach towards the stabilisation of a multiple-bonded heavy main group fragment, in this case, a phosphaalkene. An HCl adduct self-assembles with H2O into a dimeric network displaying a discrete quadrilateral hydrogen-bonded arrangement.

  • 31.
    Morales Salazar, Daniel
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Mijangos, Edgar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Pullen, Sonja
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Gao, Ming
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Functional small-molecules & polymers containing P[double bond, length as m-dash]C and As[double bond, length as m-dash]C bonds as hybrid π-conjugated materials2017Ingår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 53, nr 6, s. 1120-1123Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Stable phospha- and arsaalkenes were used to synthesize polymers containing unsaturated P[double bond, length as m-dash]C and As[double bond, length as m-dash]C moieties. The composition, chemical environment, structure, optical, and electronic properties of the monomers and polymers were elucidated. The incorporation of the heteroatom-carbon double bonded units efficiently perturbs the optoelectronics and solid state features of both monomeric and polymeric scaffolds. Proof-of principle work supports their responsive character through post-functionalisation and electrochromic behaviour. To the best of our knowledge, this is the first example of a polymer containing arsenic-carbon double bonds.

  • 32. Moser, Carmen
    et al.
    Orthaber, Andreas
    Nieger, Martin
    Belaj, Ferdinand
    Pietschnig, Rudolf
    The Homologous Series of 1,1’-Ferrocenylenebisdihalophosphanes (C5H4PX2)2Fe (X = F, Cl, Br, I): Precursors for the First Metallocene Bridged Bisphosphaalkene2006Ingår i: Dalton Transactions, s. 3879-3885Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A facile synthetic access to the homologous series of 1,1 -ferrocenylene bisdihalophosphanes Fc (PX2)2 (X =F,Cl,Br,I;Fc =1,1 -ferrocenediyl =ferrocenylene =–C5H4FeC5H4 –)is reported.The 31 PNMR spectroscopic data of this series suggest a similar electronic interaction of the –PX2 unit with the ferrocene system as in monofunctional ferrocenyldihalophosphanes.Crystal structures for Fc (PCl2)2 and Fc (PBr2)2 reveal that the nature of the halogen atom within the phosphane unit strongly in ?uences the twist angle of the ferrocene system,while leaving the other structural parameters mostly unaffected. Based on these bisdihalophosphanes,a synthetic access to the ?rst metallocene bridged bisphosphaalkene ((C5H4P =C(t -Bu)OTMS)2Fe)is reported in which the tert -butyl substituents provide suf ?cient steric pressure to control the E /Z isomeric ratio which leads to the almost exclusive formation of the most stable Z ,Z isomer out of the three possible isomers.

  • 33. Mutti, Francesco G.
    et al.
    Orthaber, Andreas
    Schrittwieser, Joerg H.
    Vries, Johannes G. de
    Pietschnig, Rudolf
    Kroutil, Wolfgang
    Simultaneous iridium catalysed oxidation and enzymatic reduction employing orthogonal reagents2010Ingår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 46, s. 8046-8048Artikel i tidskrift (Refereegranskat)
  • 34. Nauroozi, Djawed
    et al.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    The Heavier Analogues of Alkenes: A Theoretical Comparison of Unsaturated Group 15/14 Systems2016Ingår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, nr 5, s. 709-717Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this comprehensive study on unsaturated phosphorus compounds of the type R-P=CR2, R-P=N-R, and R-P=P-R, we investigated how the electronic, spectroscopic, and geometric parameters are influenced by different substituents by means of ab initio and DFT methods. The parent systems are studied with highly accurate theoretical methods and used to benchmark DFT methods. The substituent effects are rationalized based on orbital analysis of DFT calculations for phos-phaalkenes, iminophosphanes, and diphosphenes in comparison with their analogous alkenes and imines. Theoretical data are also compared to experimental data if available. This study provides a broad picture of the use of DFT methods for unsaturated main group systems. Trends obtained from this study will enable a rational molecule design for selective manipulation of electronic and geometric properties.

  • 35.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Andreas Orthaber2019Ingår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, nr 11-12, s. 1441-1442Artikel i tidskrift (Övrigt vetenskapligt)
  • 36. Orthaber, Andreas
    et al.
    Belaj, Ferdinand
    Albering, Jörg H.
    Pietschnig, Rudolf
    2,3,5,6-Tetrafluoro benzene bridged 1,4-bisphosphanes - Preparation and structure of an electron poor P-RF-P linker2010Ingår i: European Journal of Inorganic Chemistry, s. 34-37Artikel i tidskrift (Refereegranskat)
  • 37. Orthaber, Andreas
    et al.
    Belaj, Ferdinand
    Pietschnig, Rudolf
    Computational and Experimental Approaches to the Molecular Structure of the HCl Adduct of Me3PO2010Ingår i: Comptes Rendus Chimie, Vol. 13, nr 8-9, s. 923–928-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The reaction of anhydrous HCl(g) with trimethyl phosphane oxide yields trimethylhydroxyphosphonium chloride. A crystal structure analysis showed that the prevalent mesomericstructure in the solid state is the phosphonium chloride ion pair. Ab initio calculations inthe gas phase cannot reproduce these findings, whereas higher correlatedmethods (CISD)and solvation models predict the experimental structure correctly.

  • 38. Orthaber, Andreas
    et al.
    Belaj, Ferdinand
    Pietschnig, Rudolf
    Synthesis, structure and p-delocalization of a phosphaalkenyl based neutral PNP-pincer2011Ingår i: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 374, nr 1, s. 211-215Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Preparation, characterization and structural properties of a novel bis-phosphaalkenyl based PNP-pincer are reported. In this pincer the [pi]-system is delocalized over all three donor sites, which was demonstrated with DFT calculations, UV-Vis measurements and structural findings. As a consequence of this extended delocalization the [pi]-system reveals near coplanarity which is evident from the first crystal structure for an uncomplexed bisphosphaalkenyl PNP-pincer.

  • 39.
    Orthaber, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Belaj, Ferdinand
    Pietschnig, Rudolf
    Synthesis, structure and π-delocalization of a phosphaalkenyl based neutral PNP-pincer2011Ingår i: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 374, nr Copyright (C) 2015 American Chemical Society (ACS). All Rights Reserved., s. 211-215Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Prepn., characterization and structural properties of a novel bis-phosphaalkenyl based PNP-pincer (I) are reported. In this pincer the π-system is delocalized over all three donor sites, which was demonstrated with DFT calcns., UV-visible measurements and structural findings. As a consequence of this extended delocalization the π-system reveals near coplanarity which is evident from the 1st crystal structure for an uncomplexed bisphosphaalkenyl PNP-pincer. A Cu(I) complex with I was prepd. [on SciFinder(R)]

  • 40.
    Orthaber, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Borucki, Stefan
    University of Kassel, Institute of Chemistry and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Strasse 40, 34132 Kassel, Germany,.
    Shen, Wenting
    Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS Université de Rennes 1, Campus de Beaulieu, 35042 Rennes CEDEX, France.
    Rèau, Regis
    Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS Université de Rennes 1, Campus de Beaulieu, 35042 Rennes CEDEX, France.
    Lescop, Christophe
    Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS Université de Rennes 1, Campus de Beaulieu, 35042 Rennes CEDEX, France.
    Pietschnig, Rudolf
    University of Kassel, Institute of Chemistry and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Strasse 40, 34132 Kassel, Germany,.
    Coordination Behaviour of a Hexadentate 1,1′-Ferrocenylene-Bridged Bisphosphole towards Coinage Metal Centres2014Ingår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2014, nr 10, s. 1751-1759Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We describe the synthesis of a ferrocenylene-bridged bis[2,5-bis(2-pyridyl)]phosphole ligand that shows additional rotational degrees of freedom relative to its previously described p-phenylene-bridged congener. The coordination behaviour of this ferrocenylene-based bis-N,P,N pincer towards coinage metal centres MI with M = Cu and Au was explored, revealing different coordination modes with and without involvement of N donation. Upon coordination of AuI metal centres, different isomers of a bimetallic AuI complex were isolated in the crystalline solid state that showed (or did not) intramolecular aurophilic interaction. Aurophilic as well as Au–N interactions have been investigated by means of ab initio calculations.

  • 41.
    Orthaber, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Herber, Rolfe
    Pietschnig, Rudolf
    Phosphaalkenylidene bridged Ferrocenes2012Ingår i: Journal of Organometallic Chemistry, Vol. 719, s. 36-40Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The lithi ation of ferrocenylphosphane Fc-PH 2 (Fc = C5 H4 FeC5H 5) has been reinvestiga ted and both Fc- PHLi and Fc-PLi 2 have been identi fi ed by N MR-spectroscopy. The lithia ted phosph anide s have be en conver ted to the corresponding mono and bis(silylated) spec ies the latter of which gave synth etic access to an oligomer in wh ich three ferrocene units are symme trically connec ted by phosph aalke ne unit s. The charge distri bution within this oli gomer and its isomer s has been ana lyzed using DFT calculat ions which indicates that the iron atom of the central metal locene unit is slightly more positive than the terminal ones. The se fi nding s are sup ported exp eriment ally by Mößbauer spectroscopy and cyclic voltammetry.

  • 42.
    Orthaber, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Karnahl, Michael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Tschierlei, Stefanie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Streich, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Stein, Matthias
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Coordination and conformational isomers in mononuclear iron complexes with pertinence to the [FeFe] hydrogenase active site2014Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 43, nr 11, s. 4537-4549Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of six mononuclear iron complexes of the type [Fe(X-bdt)((P2N2Ph)-N-R)(CO)] ((P2N2Ph)-N-R = 1,5-diaza-3,7-diphosphaoctane, bdt = benzenedithiolate with X = H, Cl-2 or Me and R = Ph, Bn, Cyc or tert-Bu) was prepared. This new class of penta-coordinate iron complexes contains a free coordination site and a pendant base as essential structural features of the [FeFe]-hydrogenase active site. The bidentate nature of the (P2N2Ph)-N-R ligands was found to be crucial for the preferential formation of coordinatively unsaturated penta-coordinate complexes, which is supported by first principle calculations. IR-spectroscopic data suggest the presence of coordination isomers around the metal center, as well as multiple possible conformers of the (P2N2Ph)-N-R ligand. This finding is further corroborated by X-ray crystallographic and computational studies. P-31{H-1}-NMR- and IR-spectroscopic as well as electrochemical measurements show that the electronic properties of the complexes are strongly, and independently, influenced by the P-substituents at the (P2N2Ph)-N-R ligand as well as by modifications of the bdt bridge. These results illustrate the advantages of this modular platform, which allows independent and selective tuning through site specific modifications. Potential catalytic intermediates, namely singly reduced and protonated complexes, have been further investigated by spectroscopic methods and exhibit remarkable stability. Finally, their general capacity for electro-catalytic reduction of protons to molecular hydrogen was verified.

  • 43.
    Orthaber, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Löfås, Henrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Teoretisk fysik.
    Öberg, Elisabet
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Grigoriev, Anton
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Wallner, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Jafri, S.Hassan M
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Santoni, Marie-Pierre
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Leifer, Klaus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Ottosson, Henrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Cooperative Gold Nanoparticle Stabilization by Acetylenic Phosphaalkenes2015Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 54, nr 36, s. 10634-10638Artikel i tidskrift (Refereegranskat)
  • 44.
    Orthaber, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Sax, Alexander F.
    Francesconi, Kevin A.
    Oxygen Versus Sulfur: Structure and Reactivity of Substituted Arsine Oxides and Arsine Sulfides2012Ingår i: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 33, nr 1, s. 112-117Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although arsenic in its inorganic forms is a well know toxic agent, biotransformations in the environment and in the human body can produce organoarsenic compounds that are generally of much lower toxicity. Foremost among these products is a range of dimethylated arsine oxides and their analogous sulfides, which are crucial to the arsenic detoxification process. We have investigated the formation and interconversion of substituted and unsubstituted arsenicals (R(2)(2)As(=Z)R(1), R(2) = CH(3), R(1) = CH(2)CH(2)OH, CH(2)COOH; Z = S or O) with density functional theory (DFT)/B3LYP. Formation of isomers including a cyclic hydrogen bonded conformer is observed for the ethanol and acetate derivatives. Furthermore, investigating the reaction of arsine oxide with hydrogen sulfide revealed the formation of arsine sulfide via pentacoordinated trigonal bipyramidal intermediates. A tetragonal pyramidal transition state was located enabling exchange of equatorial and axial positions in the trigonal bipyramidal species. The reaction was proven exothermic for all studied substituents (Delta E(rxn) -50 to -80 kJ/mol). This fundamental study shows that H(2)S easily leads to the formation of thioorganoarsenicals. Conversion of arsine sulfides into their corresponding arsine oxides is experimentally accomplished with hydrogen peroxide, which could also be rationalized by means of ab initio calculations showing high exothermicity (Delta E(rxn) ca. -550 kJ/mol). Reactions are considered at different levels of theory (i.e., DFT, second and fourth order Moller-Plesset (MP) perturbation theory) including two solvation models for DFT, which show good agreement for resulting geometries and reaction energies. Hence, the widely used B3LYP/6-31G** combination is a suitable method for the description of molecular organoarsenicals.

  • 45.
    Orthaber, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Öberg, Elisabet
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Reuben T., Jane
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Alternative Synthesis and Structures of C-monoacetylenic Phosphaalkenes2012Ingår i: Zeitschrift für Anorganische und Allgemeines Chemie, ISSN 0044-2313, E-ISSN 1521-3749, Vol. 638, nr 14, s. 2219-2224Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An alternative synthesis of C-monoacetylenic phosphaalkenes trans-Mes*P=C(Me)(C=CR) (Mes* = 2,4,6-(Bu3Ph)-Bu-t, R = Ph, SiMe3) from C-bromophosphaalkenes cis-Mes*P=C(Me)Br using standard Sonogashira coupling conditions is described. Crystallographic studies confirm cis-trans isomerization of the P=C double bond during Pd-catalyzed cross coupling, leading exclusively to trans-acetylenic phosphaalkenes. Crystallographic studies of all synthesized compounds reveal the extend of pi-conjugation over the acetylene and P=C pi-systems.

  • 46.
    Pammer, Frank
    et al.
    Univ Ulm, Inst Organ Chem & Adv Mat 2, Albert Einstein Allee 11, D-89081 Ulm, Germany.
    Schepper, Jonas
    Univ Ulm, Inst Organ Chem & Adv Mat 2, Albert Einstein Allee 11, D-89081 Ulm, Germany.
    Gloeckler, Johannes
    Univ Ulm, Inst Analyt & Bioanalyt Chem, Albert Einstein Allee 11, D-89081 Ulm, Germany.
    Sun, Yu
    Tech Univ Kaiserslautern, Fachbereich Chem, Erwin Schrodinger Str 54, D-67663 Kaiserslautern, Germany.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Syntetisk molekylär kemi.
    Expansion of the scope of alkylboryl-bridged N -> B-ladder boranes: new substituents and alternative substrates2019Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 48, nr 27, s. 10298-10312Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of new boranes capable of forming intramolecular N -> B-heterocycles has been prepared and their properties have been studied by electrochemical methods and UV-vis-spectroscopy complemented by DFT calculations. A dimethylborane (BMe2), haloborane derivatives (BBr2, BF2, BI2) and mixed cyano/isocyano-borane (B(CN)(NC)) have been prepared by different techniques. Furthermore, 2 '-alkynyl-substituted 2-phenylpyridines bearing terminal tert-butyl- and trimethylsilyl-groups are introduced as a new class of substrates for hydroboration. Successful hydroboration with either 9H-borabicyclo[3.3.1]-nonane (9H-BBN), dimesitylborane (Mes(2)B-H), or Piers' borane ((C6F5)(2)B-H, BPF-H) furnished new pi-extended boranes capable of forming intramolecular six- or seven-membered N -> B-heterocycles (tBuBBN, SiBPF), and, in the case of Mes(2)BH, formation of a sterically crowded styrylborane (SiBMes(2)) incapable of intramolecular N -> B-coordination was observed. All the boranes listed above except BMe2 have been structurally characterized, and a study of their electrochemical properties showed that the systematic variation of the substituents on boron allows for the incremental variation of the electron affinity of the phenylpyridine-model system over a total range of >0.7 eV between alkylboranes (BMe2, BBN) and B(CN)(NC). B(CN)(NC) shows the strongest N -> B-bond (approximate to 175 kJ mol(-1)), and highest electron-affinity observed so far, and is the first example of a borane bearing an isocyano-substituent on boron.

  • 47. Pietschnig, Rudolf
    et al.
    Orthaber, Andreas
    The Relative Stabilities of 1,3-Diphospha-2-silaallene and Some of Its Isomers2006Ingår i: European Journal of Inorganic Chemistry, s. 4570-4576Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An ab initio investigation of the relative stability of 1,3-di-phospha- 2-silaallenes (RP=Si=PR) with respect to potential isomers shows that the allene isomer is not the global mini-mum throughout a series of several substituents (R = H, SiH3 , CH3 , Ph, F) ? the siladiphosphirene isomer is significantly more stable for all these substituents. The stability of the di-phosphasilaallene relative to other isomers depends on the nature of the adjacent substituents. Thus, for simple carbon and silyl substituents alternative ring-closed isomers are fa-vored over the diphosphasilaallene, which, depending on the substituent, can show silylene or phosphasilene character. The results obtained at the DFT level are compared with those at other levels of theory for the parent system.

  • 48.
    Pullen, Sonja
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Fei, Honghan
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Cohen, Seth M.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Enhanced Photochemical Hydrogen Production by a Molecular Diiron Catalyst Incorporated into a Metal-Organic Framework2013Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 135, nr 45, s. 16997-17003Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A molecular proton reduction catalyst [FeFe](dcbdt)(CO)(6) (1, dcbdt = 1,4-dicarboxylbenzene-2,3-dithiolate) with structural similarities to [FeFe]-hydrogenase active sites has been incorporated into a highly robust Zr(IV)-based metal-organic framework (MOF) by postsynthetic exchange (PSE). The PSE protocol is crucial as direct solvothermal synthesis fails to produce the functionalized MOF. The molecular integrity of the organometallic site within the MOF is demonstrated by a variety of techniques, including X-ray absorption spectroscopy. In conjunction with [Ru(bpy)(3)](2+) as a photosensitizer and ascorbate as an electron donor, MOF-[FeFe](dcbdt)(CO)(6) catalyzes photochemical hydrogen evolution in water at pH 5. The immobilized catalyst shows substantially improved initial rates and overall hydrogen production when compared to a reference system of complex 1 in solution. Improved catalytic performance is ascribed to structural stabilization of the complex when incorporated in the MOF as well as the protection of reduced catalysts 1(-) and 1(2-) from undesirable charge recombination with oxidized ascorbate.

  • 49.
    Ren, Yi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Pietschnig, Rudolf
    Baumgartner, Thomas
    Perfluorophenylene-Bridged Bisphospholes: Synthesis and Unexpected Photophysical Properties2013Ingår i: Dalton Transactions, Vol. 42, s. 5314-5321Artikel i tidskrift (Refereegranskat)
  • 50.
    Sawadjoon, Supaporn
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Sjöberg, Per J. R.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Eriksson, Lars
    Samec, Joseph S. M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Equilibrium Study of Pd(dba)2 and P(OPh)3 in the Pd-Catalyzed Allylation of Aniline by Allyl Alcohol2014Ingår i: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 33, nr 1, s. 249-253Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reaction of Pd(dba)2 and P(OPh)3 shows a unique equilibrium where the Pd[P(OPh)3]3 complex is favored over both Pd(dba)[P(OPh)3]2 and Pd[P(OPh)3]4 complexes at room temperature. At a lower temperature, Pd[P(OPh)3]4 becomes the most abundant complex in solution. X-ray studies of Pd[P(OPh)3]3 and Pd(dba)[P(OPh)3]2 complexes show that both complexes have a trigonal geometry with a Pd–P distance of 2.25 Å due to the π-acidity of the phosphite ligand. In solution, pure Pd(dba)[P(OPh)3]2 complex equilibrates to the favored Pd[P(OPh)3]3 complex, which is the most stable complex of those studied, and also forms the most active catalytic species. This catalyst precursor dissociates one ligand to give the reactive Pd[P(OPh)3]2, which performs an oxidative addition of nonmanipulated allyl alcohol to generate the π-allyl-Pd[P(OPh)3]2 intermediate according to ESI-MS studies.

12 1 - 50 av 66
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