uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 55) Show all publications
Liu, T., Guo, M., Orthaber, A., Lomoth, R., Lundberg, M., Ott, S. & Hammarström, L. (2018). Accelerating proton-coupled electron transfer of metal hydrides in catalyst model reactions. Nature Chemistry, 10(8), 881-887
Open this publication in new window or tab >>Accelerating proton-coupled electron transfer of metal hydrides in catalyst model reactions
Show others...
2018 (English)In: Nature Chemistry, ISSN 1755-4330, E-ISSN 1755-4349, Vol. 10, no 8, p. 881-887Article in journal (Refereed) Published
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.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-357209 (URN)10.1038/s41557-018-0076-x (DOI)000439420400015 ()30013192 (PubMedID)
Funder
Swedish Research Council, 2016-04271Knut and Alice Wallenberg Foundation, 2011.0067
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-09-27Bibliographically approved
Gupta, A. K. & Orthaber, A. (2018). Alkynyl Coinage Metal Clusters and Complexes-Syntheses, Structures, and Strategies. Chemistry - A European Journal, 24(30), 7536-+
Open this publication in new window or tab >>Alkynyl Coinage Metal Clusters and Complexes-Syntheses, Structures, and Strategies
2018 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, no 30, p. 7536-+Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
Keywords
alkynyl ligands, cluster compounds, coinage metals, metallophilic interactions, X-ray crystallography
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-357737 (URN)10.1002/chem.201704667 (DOI)000434089500001 ()29390168 (PubMedID)
Available from: 2018-08-30 Created: 2018-08-30 Last updated: 2018-10-05Bibliographically approved
Kovacs, D., Phipps, D., Orthaber, A. & Borbas, K. E. (2018). Highly luminescent lanthanide complexes sensitised by tertiary amide-linked carbostyril antennae. Dalton Transactions, 47(31), 10702-10714
Open this publication in new window or tab >>Highly luminescent lanthanide complexes sensitised by tertiary amide-linked carbostyril antennae
2018 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, no 31, p. 10702-10714Article in journal (Refereed) Published
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.

National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-363106 (URN)10.1039/c8dt01270a (DOI)000441151700043 ()29923567 (PubMedID)
Funder
Swedish Research Council, 2013-4655Swedish Research Council, 2017-04077
Available from: 2018-10-15 Created: 2018-10-15 Last updated: 2018-10-15Bibliographically approved
Morales Salazar, D., Gupta, A. K. & Orthaber, A. (2018). Reactivity studies of an imine-functionalised phosphaalkene; unusual electrostatic and supramolecular stabilisation of a σ2λ3-phosphorus motif via hydrogen bonding. Dalton Transactions, 47, 10404-10409
Open this publication in new window or tab >>Reactivity studies of an imine-functionalised phosphaalkene; unusual electrostatic and supramolecular stabilisation of a σ2λ3-phosphorus motif via hydrogen bonding
2018 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, p. 10404-10409Article in journal (Refereed) Published
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.

Keywords
molecular inorganic chemistry, organophosphorus chemistry, hydrogen bonding, supramolecular chemistry, crystal design, phosphaalkenes
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-360030 (URN)10.1039/C8DT01607K (DOI)000441151700010 ()
Funder
Swedish Research Council, 2017-03727Stiftelsen Olle Engkvist Byggmästare
Note

Title inWoS: Reactivity studies of an imine-functionalised phosphaalkene; unusual electrostatic and supramolecular stabilisation of a sigma(23)-phosphorus motif via hydrogen bonding

Available from: 2018-09-08 Created: 2018-09-08 Last updated: 2018-10-23Bibliographically approved
Akkarasamiyo, S., Sawadjoon, S., Orthaber, A. & Samec, J. S. M. (2018). Tsuji-Trost Reaction of Non-Derivatized Allylic Alcohols. Chemistry - A European Journal, 24(14), 3488-3498
Open this publication in new window or tab >>Tsuji-Trost Reaction of Non-Derivatized Allylic Alcohols
2018 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, no 14, p. 3488-3498Article in journal (Refereed) Published
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.

Keywords
asymmetric catalysis, cuspareine, OH activation, palladium, Tsuji-Trost reaction
National Category
Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-350623 (URN)10.1002/chem.201705164 (DOI)000426764400020 ()29178406 (PubMedID)
Available from: 2018-05-22 Created: 2018-05-22 Last updated: 2018-05-22Bibliographically approved
Calard, F., Wani, I. H., Hayat, A., Jarrosson, T., Lere-Porte, J.-P., Jafri, S. H., . . . Orthaber, A. (2017). Designing sterically demanding thiolate coated AuNPs for electrical characterization of BPDT in a NP-molecule-nanoelectrode platform. MOLECULAR SYSTEMS DESIGN & ENGINEERING, 2(2), 133-139
Open this publication in new window or tab >>Designing sterically demanding thiolate coated AuNPs for electrical characterization of BPDT in a NP-molecule-nanoelectrode platform
Show others...
2017 (English)In: MOLECULAR SYSTEMS DESIGN & ENGINEERING, ISSN 2058-9689, Vol. 2, no 2, p. 133-139Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2017
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-323512 (URN)10.1039/c6me00095a (DOI)000400987200003 ()
Available from: 2017-06-14 Created: 2017-06-14 Last updated: 2018-04-12Bibliographically approved
Blunder, M., Orthaber, A., Bauer, R., Bucar, F. & Kunert, O. (2017). Efficient identification of flavones, flavanones and their glycosides in routine analysis via off-line combination of sensitive NMR and HPLC experiments. Food Chemistry, 218, 600-609
Open this publication in new window or tab >>Efficient identification of flavones, flavanones and their glycosides in routine analysis via off-line combination of sensitive NMR and HPLC experiments
Show others...
2017 (English)In: Food Chemistry, ISSN 0308-8146, E-ISSN 1873-7072, Vol. 218, p. 600-609Article in journal (Refereed) Published
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.

Keywords
NMR, Flavones, Flavanones, HPLC, MS, Data base
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-306576 (URN)10.1016/j.foodchem.2016.09.077 (DOI)000386409700078 ()27719955 (PubMedID)
Available from: 2016-10-28 Created: 2016-10-28 Last updated: 2017-12-28Bibliographically approved
Morales Salazar, D., Mijangos, E., Pullen, S., Gao, M. & Orthaber, A. (2017). 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 materials. Chemical Communications, 53(6), 1120-1123
Open this publication in new window or tab >>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 materials
Show others...
2017 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 53, no 6, p. 1120-1123Article in journal (Refereed) Published
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.

National Category
Organic Chemistry Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-312610 (URN)10.1039/c6cc08736a (DOI)000393978300026 ()28054056 (PubMedID)
Funder
Lars Hierta Memorial FoundationStiftelsen Olle Engkvist ByggmästareSwedish Research Council, 2013-4763
Available from: 2017-01-12 Created: 2017-01-12 Last updated: 2017-11-29Bibliographically approved
Xiong, R., Bornhof, A.-B., Arkhypchuk, A., Orthaber, A. & Borbas, E. (2017). Furan- and Thiophene-Based Auxochromes Red-shift Chlorin Absorptions and Enable Oxidative Chlorin Polymerizations. Chemistry - A European Journal, 23(17), 4089-4095
Open this publication in new window or tab >>Furan- and Thiophene-Based Auxochromes Red-shift Chlorin Absorptions and Enable Oxidative Chlorin Polymerizations
Show others...
2017 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, no 17, p. 4089-4095Article in journal (Refereed) Published
Abstract [en]

The de novo syntheses of chemically stable chlorins with five-membered heterocyclic (furane, thiophene, formylfurane and formylthiophene) substituents in selected meso- and beta-positions are reported. Heterocycle incorporation in the 3- and 13-positions shifted the chlorin absorption and emission to the red (up to lambdaem =680 nm), thus these readily incorporated substituents function analogously to auxochromes present in chlorophylls, for example, formyl and vinyl groups. Photophysical, theoretical and X-ray crystallographic experiments revealed small but significant differences between the behavior of the furan- and the thiophene-based auxochromes. Four regioisomeric bis-thienylchlorins (3,10; 3,13, 3,15 and 10,15) were oxidatively electropolymerized; the chlorin monomer geometry had a profound impact on the polymerization efficiency and the electrochemical properties of the resulting material. Chemical co-polymerization of 3,13-bis-thienylchlorin with 3-hexylthiophene yielded an organic-soluble red-emitting polymer.

Keywords
chlorins, electrochemistry, photophysics, polymerization, porphyrinoids
National Category
Organic Chemistry
Research subject
Chemistry with specialization in Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-317978 (URN)10.1002/chem.201604655 (DOI)000399312700011 ()27859811 (PubMedID)
Funder
Stiftelsen Olle Engkvist ByggmästareSwedish Research Council, 2013-4655Swedish Research Council, 2013-4763
Available from: 2017-03-22 Created: 2017-03-22 Last updated: 2017-12-28Bibliographically approved
Gupta, A. K., Akkarasamiyo, S. & Orthaber, A. (2017). Rich Coordination Chemistry of pi-Acceptor Dibenzoarsole Ligands. Inorganic Chemistry, 56(8), 4504-4511
Open this publication in new window or tab >>Rich Coordination Chemistry of pi-Acceptor Dibenzoarsole Ligands
2017 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 56, no 8, p. 4504-4511Article in journal (Refereed) Published
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.

National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-322810 (URN)10.1021/acs.inorgchem.7b00100 (DOI)000399625600030 ()28345894 (PubMedID)
Available from: 2017-06-08 Created: 2017-06-08 Last updated: 2017-06-08Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5403-9902

Search in DiVA

Show all publications