uu.seUppsala University Publications
Change search
Refine search result
1 - 24 of 24
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1.
    Alvi, Muhammad Rouf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Jahn, Burkhard O.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Tibbelin, Julius
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Baumgartner, Judith
    Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria.
    Gómez, Cesar Pay
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ottosson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Highly Efficient and Convenient Acid Catalyzed Hypersilyl Protection of Alcohols and Thiols by Tris(trimethylsilyl)silyl-N,N-dimethylmethaneamide2012Article in journal (Other academic)
    Abstract [en]

    Tris(trimethylsilyl)silyl-N,N-dimethylmethaneamide, herein named hypersilylamide, is a convenient and efficient source of the hypersilyl group in the first widely applicable acid catalyzed protocol for silyl group protection of primary, secondary, tertiary alkyl as well as aryl alcohols and thiols in high yields. The sole by-product is N,N-dimethylformamide (DMF) and a range of solvents can be used, including DMF. A high selectivity in the protection of diols can be achieved, also for diols with very small differences in the steric demands at the two hydroxyl groups. Moreover, in the protection of equivalent alcohol and thiol sites the protection of the alcohol is faster, allowing for selective protection in high yields. Quantum chemical calculations at the M062X hybrid meta density functional theory level give insights on the mechanism for the catalytic process. Finally, the hypersilyl group is easily removed from all protected alcohols and thiols examined herein by irradiation at 254 nm.

  • 2.
    Andersson, Claes-Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Synthesis and characterization of a ferrocene-linked bis-fullerene[60] dumbbell2012In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 41, no 8, p. 2374-2381Article in journal (Refereed)
    Abstract [en]

    A new [60]fullerene dumbbell consisting of two fulleropyrrolidines connected to a central ferrocene unit by amide linkages has been prepared and fully characterized by elemental analysis, 1H NMR, UV/Vis, fluorescence and mass spectrometry. The electrochemical properties as determined by cyclic voltammetry show ground state electronic communication between the ferrocene and the fullerene units. In addition, the preparaton of a ferrocene building block for an alternative linking approach is presented.

  • 3.
    Arkhypchuk, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Mihali, Viorica Alina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Ehlers, Andreas
    VU University Amsterdam.
    Lammertsma, Koop
    VU University Amsterdam.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Phosphorus Heterocylces from Phosphinophosphonates and α,β-Unsaturated KetonesManuscript (preprint) (Other academic)
  • 4.
    Arkhypchuk, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Svyaschenko, Yurii
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Mechanism of the Phospha-Wittig-Horner Reaction2013In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 52, no 25, p. 6484-6487Article in journal (Refereed)
  • 5.
    Cadu, Alban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Upadhyay, Puspesh K.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Andersson, Pher G.
    Stockholm University.
    Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines2013In: Asian Journal of Organic Chemistry, ISSN 2193-5807, Vol. 2, no 12, p. 1061-1065Article in journal (Refereed)
    Abstract [en]

    Asymmetric hydrogenation of ortho-substituted pyridines catalyzed by N,P-ligated iridium is demonstrated. To facilitate this reaction, the aromaticity of the pyridines was weakened by forming N-iminopyridium ylides. The reactions give very high conversions, and after a single recrystallization, excellent ee of up to 98 % was obtained. This method lends itself to the synthesis of chiral piperidine building blocks.

  • 6. Coleman, V. A.
    et al.
    Knut, Ronny
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Grennberg, H.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Jansson, U.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Quinlan, R.
    Holloway, B. C.
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Defect Formation In Graphene Nanosheets By Acid Treatment: An X-Ray Absorption Spectroscopy And Density Functional Theory Study2008In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 41, no 6, p. 062001-4Article in journal (Refereed)
    Abstract [en]

    In-plane defects have been introduced into graphene nanosheets by treatment with hydrochloric acid. Acid treatment induces bond cleavage in the C–C network via electrophilic attack. These resultant vacancy sites will then undergo further reactions with the surrounding ambient to produce C–O and C–H bonds. A σ* resonance at 287 eV in the carbon K-edge x-ray absorption spectra is observed with acid treatment and is assigned to C–O states. Theoretical modelling of a di-vacancy in a graphene bilayer reproduces all essential features of this resonance and in addition predicts a metallic conductivity of states around this vacancy. The possibility of engineering the properties of graphene via the routes explored here is an important step towards establishing strategies for building devices based on this material.

  • 7.
    Esfandiarfard, Keyhan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Ott, Sascha
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Synthesis of 2,6-Dimesitylphenyl-C,C-dibromophosphaalkene2015In: Phosphorus Sulfur and Silicon and the Related Elements, ISSN 1042-6507, E-ISSN 1563-5325, Vol. 190, no 5-6, p. 816-820Article in journal (Refereed)
    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.

  • 8. Långström, B
    et al.
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Halldin, Christer
    Svärd, Hans
    Bergson, Göran
    Synthesis of some 11C-labelled alkaloids1982In: Chemica Scripta, Vol. 20, p. 46-49Article in journal (Refereed)
  • 9.
    Mijangos, Edgar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Roy, Souvik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Pullen, Sonja
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Evaluation of two- and three-dimensional electrode platforms for the electrochemical characterization of organometallic catalysts incorporated in non-conducting metal-organic frameworks2017In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 46, no 15, p. 4907-4911Article in journal (Refereed)
    Abstract [en]

    The development of a reliable platform for the electrochemical characterization of a redox-active molecular diiron complex, [FeFe], immobilized in a non-conducting metal organic framework (MOF), UiO-66, based on glassy-carbon electrodes is reported. Voltammetric data with appreciable current responses can be obtained by the use of multiwalled carbon nanotubes (MWCNT) or mesoporous carbon (CB) additives that function as conductive scaffolds to interface the MOF crystals in "three-dimensional" electrodes. In the investigated UiO-66-[FeFe] sample, the low abundance of [FeFe] in the MOF and the intrinsic insulating properties of UiO-66 prevent charge transport through the framework, and consequently, only [FeFe] units that are in direct physical contact with the electrode material are electrochemically addressable.

  • 10.
    Morales Salazar, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Mijangos, Edgar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Pullen, Sonja
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Gao, Ming
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    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 materials2017In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 53, no 6, p. 1120-1123Article in journal (Refereed)
    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.

  • 11. 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 Bisphosphaalkene2006In: Dalton Transactions, p. 3879-3885Article in journal (Refereed)
    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.

  • 12.
    Nordlund, Michael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Mono- and diamides of 1,1’-dicarboxyferrocene: a stepwise approach to ferrocene-linked triadsManuscript (preprint) (Other academic)
    Abstract [en]

    An improved route to the monomethyl ester of 1,1´-dicarboxyferrocene is described. The compound is a key intermediate for the assembly of ferrocene-bridged triads by stepwise amidation. This renders possible symmetric as well as non-symmetric diamides, exemplified by the preparaton of a symmetric ferrocene-linked fulleropyrrolidine dumbbell and a non-symmetric fulleropyrrolidine-ferrocene-tryptophan triad.

  • 13.
    Nordlund, Michael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Towards [60]fullerene-based molecular wires: amide-interlinked ferrocene-[60]fullerene oligomersManuscript (preprint) (Other academic)
    Abstract [en]

    Design and synthesis of amide-linked ferrocene-fulleropyrrolidine oligomers is presented, with initial characterisation that confirms products containing three or four ferrocene-bridged fullerene units. Side-products have been identified; the encountered issues concerning their formation and general solubility motivated modifications of the synthesis strategy.

  • 14.
    Nordlund, Michael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Bhandary, Sumanta
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Side-selective self-assembly of graphene and FLG on piezoelectric PVDF from suspension2016In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 49, no 7, article id 07LT01Article in journal (Refereed)
    Abstract [en]

    The deposition of few-layer graphene by self-assembly from suspension onto a piezoelectric polymer substrate is presented. The graphene self-assembles with negligible overlap between flakes, and with high selectivity for one of the faces of the substrate, an observation which is discussed and rationalized. A computational study on a model system further confirms the theory and supports the experimental results. The highest obtained degree of surface coverage was estimated to 77%.

  • 15.
    Nordlund, Michael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Günther, Tyran
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Catenane dimer formation in tether-assisted trans-bis-pyrrolidination of [60]fullereneManuscript (preprint) (Other academic)
    Abstract [en]

    Trans-bis-pyrrolidination of [60]fullerene employing a new bis-aldehyde tether with appended octadecyloxy substituents proceeded to give the desired product as well as catenane dimers. For pyrrolidinations employing sarcosine, the products were separable, and characterisation by NMR spectroscopy, including diffusion-ordered spectroscopy (DOSY), provided unambiguous proof that the high-mass product was a symmetric non-covalent catenane. No catenane or other high-mass products were observed for reactions employing a tether without the octadecyloxy substituents.

  • 16. 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 linker2010In: European Journal of Inorganic Chemistry, p. 34-37Article in journal (Refereed)
  • 17. Orthaber, Andreas
    et al.
    Belaj, Ferdinand
    Pietschnig, Rudolf
    Computational and Experimental Approaches to the Molecular Structure of the HCl Adduct of Me3PO2010In: Comptes Rendus Chimie, Vol. 13, no 8-9, p. 923–928-Article in journal (Refereed)
    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.

  • 18.
    Orthaber, Andreas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Belaj, Ferdinand
    Pietschnig, Rudolf
    Synthesis, structure and π-delocalization of a phosphaalkenyl based neutral PNP-pincer2011In: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 374, no Copyright (C) 2015 American Chemical Society (ACS). All Rights Reserved., p. 211-215Article in journal (Refereed)
    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)]

  • 19.
    Orthaber, Andreas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Herber, Rolfe
    Pietschnig, Rudolf
    Phosphaalkenylidene bridged Ferrocenes2012In: Journal of Organometallic Chemistry, Vol. 719, p. 36-40Article in journal (Refereed)
    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.

  • 20.
    Parada, Giovanny A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Synthesis of Biomimetic Systems for Proton and Electron Transfer Reactions in the Ground and Excited State2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A detailed understanding of natural photosynthesis provides inspiration for the development of sustainable and renewable energy sources, i.e. a technology that is capable of converting solar energy directly into chemical fuels. This concept is called artificial photosynthesis. The work described in this thesis contains contributions to the development of artificial photosynthesis in two separate areas.

    The first one relates to light harvesting with a focus on the question of how electronic properties of photosensitizers can be tuned to allow for efficient photo-induced electron transfer processes. The study is based on a series of bis(tridentate)ruthenium(II) polypyridyl complexes, the geometric properties of which make them highly appealing for the construction of linear donor-photosensitizer-acceptor arrangements for efficient vectorial photo-induced electron transfer reactions. The chromophores possess remarkably long lived 3MLCT excited states and it is shown that their excited-state oxidation strength can be altered by variations of the ligand scaffold over a remarkably large range of 900 mV.

    The second area of relevance to natural and artificial photosynthesis that is discussed in this thesis relates to the coupled movement of protons and electrons. The delicate interplay between these two charged particles regulates thermodynamic and kinetic aspects in many key elementary steps of natural photosynthesis, and further studies are needed to fully understand this concept. The studies are based on redox active phenols with intramolecular hydrogen bonds to quinolines. The compounds thus bear a strong resemblance to the tyrosine/histidine couple in photosystem II, i.e. the water-plastoquinone oxidoreductase enzyme in photosynthesis. The design of the biomimetic models is such that the distance between the proton donor and acceptor is varied, enabling studies on the effect the proton transfer distance has on the rate of proton-coupled electron transfer reactions. The results of the studies have implications for the development of artificial photosynthesis, in particular in connection with redox leveling, charge accumulation, as well as electron and proton transfer.

    In addition to these two contributions, the excited-state dynamics of the intramolecular hydrogen-bonded phenols was investigated, thereby revealing design principles for technological applications based on excited-state intramolecular proton transfer and photoinduced tautomerization.

    List of papers
    1. Tuning the Electronics of Bis(tridentate)ruthenium(II) Complexes with Long-Lived Excited States: Modifications to the Ligand Skeleton beyond Classical Electron Donor or Electron Withdrawing Group Decorations
    Open this publication in new window or tab >>Tuning the Electronics of Bis(tridentate)ruthenium(II) Complexes with Long-Lived Excited States: Modifications to the Ligand Skeleton beyond Classical Electron Donor or Electron Withdrawing Group Decorations
    Show others...
    2013 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 52, no 9, p. 5128-5137Article in journal (Refereed) Published
    Abstract [en]

    A series of homoleptic bis(tridentate) [Ru-(L)(2)](2+) (1, 3) and heteroleptic [Ru(L)(dqp)](2+) complexes (2, 4) [L = dqxp (1, 2) or dNinp (3, 4); dqxp = 2,6-di(quinoxalin-5-yl)pyridine, dNinp = 2,6-di(N-7-azaindol-1-yl)pyridine, dqp = 2,6-di(quinolin-8-yl)pyridine) was prepared and in the case of 2 and 4 structurally characterized. The presence of dqxp and dNinp in 1-4 result in anodically shifted oxidation potentials of the Ru3+/2+ couple compared to that of the archetypical [Ru(dqp)(2)](2+) (5), most pronounced for [Ru(dqxp)(2)](2+) (1) with a shift of +470 mV. These experimental findings are corroborated by DFT calculations, which show contributions to the complexes' HOMOs by the polypyridine ligands, thereby stabilizing the HOMOs and impeding electron extraction. Complex 3 exhibits an unusual electronic absorption spectrum with its lowest energy maximum at 382 nm. TD-DFT calculations suggest that this high-energy transition is caused by a localization of the LUMO on the central pyridine fragments of the dNinp ligands in 3, leaving the lateral azaindole units merely spectator fragments. The opposite is the case in 1, where the LUMO experiences large stabilization by the lateral quinorralines. Owing to the differences in LUMO energies, the complexes' reduction potentials differ by about 900 mV [E-1/2(1(2+/1+)) = -1.17 V, E-c,E-p(3(2+/1+)) = -2.06 V vs Fc(+/0)]. As complexes 1-4 exhibit similar excited state energies of around 1.80 V, the variations of the lateral heterocycles allow the tuning of the complexes' excited state oxidation strengths over a range of 900 mV. Complex 1 is the strongest excited state oxidant of the series, exceeding even [Ru(bpy)(3)](2+) by more than 200 mV. At room temperature, complex 3 is nonemissive, whereas complexes 1, 2, and 4 exhibit excited state lifetimes of 255, 120, and 1570 ns, respectively. The excited state lifetimes are thus somewhat shortened compared to that of 5 (3000 ns) but still acceptable to qualify the complexes as photosensitizers in light-induced charge-transfer schemes, especially for those that require high oxidative power.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-202924 (URN)10.1021/ic400009m (DOI)000318669400050 ()
    Available from: 2013-07-01 Created: 2013-07-01 Last updated: 2017-12-06Bibliographically approved
    2. Synthesis of Phenol-Quinolines with Intramolecular Hydrogen-Bonds of Different Strength
    Open this publication in new window or tab >>Synthesis of Phenol-Quinolines with Intramolecular Hydrogen-Bonds of Different Strength
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Keyword
    Hydrogen-bond strength, phenols, stereochemistry, Friedländer annulation, proton-coupled electron transfer
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-251469 (URN)
    Available from: 2015-04-19 Created: 2015-04-19 Last updated: 2015-07-07
    3. Control over Excited State Intramolecular Proton Transfer and Photoinduced Tautomerization: Influence of the Hydrogen-Bond Geometry
    Open this publication in new window or tab >>Control over Excited State Intramolecular Proton Transfer and Photoinduced Tautomerization: Influence of the Hydrogen-Bond Geometry
    Show others...
    2015 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 21, no 17, p. 6362-6366Article in journal (Refereed) Published
    Abstract [en]

    The influence of H-bond geometry on thedynamics of excited state intramolecular proton transfer(ESIPT) and photoinduced tautomerization in a series ofphenol-quinoline compounds is investigated. Control overthe proton donor–acceptor distance (dDA) and dihedralangle between the proton donor–acceptor subunits isachieved by introducing methylene backbone straps ofincreasing lengths to link the phenol and quinoline. Wedemonstrate that a long dDA correlates with a higher barrierfor ESIPT, while a large dihedral angle opens highlyefficient deactivation channels after ESIPT, preventing theformation of the fully relaxed tautomer photoproduct.

    Keyword
    excited state, fluorescence, hydrogen bonds, intramolecular proton transfer, phenols, tautomerism
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-251468 (URN)10.1002/chem.201500244 (DOI)000352796100008 ()
    Available from: 2015-04-19 Created: 2015-04-19 Last updated: 2017-12-04Bibliographically approved
    4. A Study of Concerted Proton-Coupled Electron Transfer as a Function of Intramolecular Proton Tunneling Distance
    Open this publication in new window or tab >>A Study of Concerted Proton-Coupled Electron Transfer as a Function of Intramolecular Proton Tunneling Distance
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Keyword
    proton-coupled electron transfer, phenols, quinolines
    National Category
    Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-251470 (URN)
    Available from: 2015-04-19 Created: 2015-04-19 Last updated: 2015-07-07
  • 21. Pietschnig, Rudolf
    et al.
    Orthaber, Andreas
    The Relative Stabilities of 1,3-Diphospha-2-silaallene and Some of Its Isomers2006In: European Journal of Inorganic Chemistry, p. 4570-4576Article in journal (Refereed)
    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.

  • 22.
    Ren, Yi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Pietschnig, Rudolf
    Baumgartner, Thomas
    Perfluorophenylene-Bridged Bisphospholes: Synthesis and Unexpected Photophysical Properties2013In: Dalton Transactions, Vol. 42, p. 5314-5321Article in journal (Refereed)
  • 23.
    Rickaby, Rosalind E. M.
    et al.
    Dept. of Earth Sciences, Oxford University, UK.
    Henderiks, Jorijntje
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Young, Jodi N.
    Perturbing phytoplankton: response and isotopic fractionation with changing carbonate chemistry in two coccolithophore species2010In: Climate of the Past, ISSN 1814-9324, Vol. 6, p. 771-785Article in journal (Refereed)
    Abstract [en]

    All species of coccolithophore appear to respond to perturbations of carbonate chemistry in a different way. Here, we show that the degree of malformation, growthrate and stable isotopic composition of organic matter and carbonate produced by two contrasting species of coccolithophore (Gephyrocapsa oceanica and Coccolithus pelagicusssp. braarudii) are indicative of differences between their photosynthetic and calcification response to changing DIC levels (ranging from 1100 to 7800 μmol kg−1) at constant pH (8.13±0.02). Gephyrocapsa oceanica thrived under all conditions of DIC, showing evidence of increased growth rates at higher DIC, but C. braarudii was detrimentally affected at high DIC showing signs of malformation, and decreased growth rates. The carbon isotopic fractionation into organic matter and the coccoliths suggests that C. braarudii utilises a common internal pool of carbon for calcification and photosynthesis but G. oceanica relies on independent supplies for each process. All coccolithophores appear to utilize bicarbonate as their ultimate source of carbon for calcification resulting in the release of a proton. But, we suggest that this proton can be harnessed to enhance the supply of CO2(aq) for photosynthesis either from a large internal HCO−3 pool which acts as a pH buffer (C. braarudii), or pumped externally to aid the diffusive supply of CO2 across the membrane from the abundant HCO−3 (G. oceanica), likely mediated by an internal and external carbonic anhydrase respectively. Our simplified hypothetical spectrum of physiologies may provide a context to understand different species response to changing pH and DIC, the species specific Ep and calcite “vital effects”, as well as accounting for geological trends in coccolithophore cell size.

  • 24.
    Shameem, Muhammad Anwar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Organophosphorus Compounds in Organic Electronics2016In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 22, no 31, p. 10718-10735Article in journal (Refereed)
    Abstract [en]

    This Minireview describes recent advances of organophosphorus compounds as opto-electronic materials in the field of organic electronics. The progress of (hetero-) phospholes, unsaturated phosphanes, and trivalent and pentavalent phosphanes since 2010 is covered. The described applications of organophosphorus materials range from single molecule sensors, field effect transistors, organic light emitting diodes, to polymeric materials for organic photovoltaic applications.

1 - 24 of 24
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf