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.
    Devaraj, Karthik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Ingner, Fredric
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Sollert, Carina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Gates, Paul J.
    Univ Bristol, Sch Chem, Cantocks Close, Bristol BS8 1TS, Avon, England.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Pilarski, Lukasz T.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Arynes and Their Precursors from Arylboronic Acids via Catalytic C-H Silylation2019In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 84, no 9, p. 5863-5871Article in journal (Refereed)
    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.

  • 2.
    Green, Joshua P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry. Imperial Coll London, Dept Chem, London SW7 2AZ, England.
    Cha, Hyojung
    Imperial Coll London, Dept Chem, London SW7 2AZ, England.
    Shahid, Munazza
    Imperial Coll London, Dept Chem, London SW7 2AZ, England.
    Creamer, Adam
    Imperial Coll London, Dept Chem, London SW7 2AZ, England.
    Durrant, James R.
    Imperial Coll London, Dept Chem, London SW7 2AZ, England.
    Heeney, Martin
    Imperial Coll London, Dept Chem, London SW7 2AZ, England.
    Dithieno[3,2-b:2,3-d]arsole-containing conjugated polymers in organic photovoltaic devices2019In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 48, no 20, p. 6676-6679Article in journal (Refereed)
    Abstract [en]

    Arsole-derived conjugated polymers are a relatively new class of materials in the field of organic electronics. Herein, we report the synthesis of two new donor polymers containing fused dithieno[3,2-b:2,3-d]arsole units and report their application in bulk heterojunction solar cells for the first time. Devices based upon blends with PC71BM display high open circuit voltages around 0.9 V and demonstrate power conversion efficiencies around 4%.

  • 3.
    Green, Joshua P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Wells, Jordann A. L.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Heavier pnictogens - treasures for optical electronic and reactivity tuning2019In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 48, no 14, p. 4460-4466Article, review/survey (Refereed)
    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.

  • 4.
    Gupta, Arvind Kumar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Green, Joshua P.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Rearrangement and redistribution reaction of Ph2PCH2TMS with PhAsCl2 or AsCl32019In: Phosphorus Sulfur and Silicon and the Related Elements, ISSN 1042-6507, E-ISSN 1563-5325, Vol. 194, no 10, p. 967-971Article in journal (Refereed)
    Abstract [en]

    The attempted synthesis of bis(diphenylphosphinomethyl) phenylarsane and tris(diphenylphosphinomethyl) arsane through condensation of chloro arsanes and diphenyl (trimethylsilylmethyl) phosphane yielded a number of side products originating from migratory and redox-reactions in addition to the targeted ligands. An unexpected, 1,3,4-phosphadiarssolan-1-ium salt was obtained and crystallographically characterized as an A-shaped chlorido adduct. [GRAPHICS] .

  • 5.
    Gupta, Arvind Kumar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Morales Salazar, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Solvent and Counter-Ion Induced Coordination Environment Changes Towards Ag-I Coordination Polymers2019In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2019, no 33, p. 3740-3744Article in journal (Refereed)
    Abstract [en]

    A series of silver coordination polymers based on the 9,9 '-bis(4,5-diazafluorene) (BDF-H-2) ligand is presented. The choice of counterions and reaction conditions dictate the observed topology on the final systems by influencing the silver coordination environment. Coordination modes, flexibility of the ligand and extended pi-pi stacking interactions have allowed the preparation and crystallographic characterisation of one 1D- and three 2D-coordination polymers: 1D-[Ag(BDF-H-2)(DMSO)](n)(X)(n) (where X = OTf- and ClO4-); 1D-[Ag-2(BDF-H-2) m(1)-(TfO)(2),m(2)-(TfO)(2)](n)(TfO)(n), and 2D-[Ag-2(BDF-H-2)(3)](n)(PF6)(2n).

  • 6.
    Gupta, Arvind Kumar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Facile synthesis of silver alkynide cluster and coordination polymers using picolinic acid as a co-ligand2019In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 48, no 44, p. 16518-16524Article in journal (Refereed)
    Abstract [en]

    We describe five 1D-coordination polymers and two discrete silver clusters consisting of alkynides and picolinic carboxylates as co-ligands. In some cases, DMSO or EtOH further solvated the structural motifs. Utilising the sterically demanding tri-isopropylsilyl acetylene afforded a tridecanuclear cluster that possessed an unprecedented core with a silver center surrounded by six octahedrally arranged silver atoms.

  • 7.
    Gupta, Arvind Kumar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    The Self-Assembly of [{Ag-3(C (CBu)-Bu-t)(2)}(n)](n+) Building Units into a Template-Free Cuboctahedron and Anion-Encapsulating Silver Cages2019In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 58, no 23, p. 16236-16240Article in journal (Refereed)
    Abstract [en]

    We describe the controlled synthesis of silver acetylide clusters based on a simple polymeric [Ag3L2](+) (L = -C (CBu)-Bu-t) building block. A linear one-dimensional polymeric structure shows alternating pyramidal motifs and is the basic repeating unit forming discrete molecular cages (pentamers [X subset of Ag15L10](4+) and hexamers [PF6 subset of Ag18L12](5+)) obtained by incorporating suitable templates. These motifs and a rare template-free cuboctahedral [Ag12L8](4+) cluster (tetramer) were crystallographically characterized.

  • 8.
    Johnson, Ben A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Interrogating Diffusional Mass and Charge Transport in Catalytic Metal-Organic Frameworks2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Molecular catalysts are efficient and selective for the electrochemical conversion of small molecules for energy conversion. Application of molecular species in a large-scale industrial setting requires stabilization in a heterogeneous support material. Metal-organic frameworks (MOFs), having high surface areas for increased active site density, have shown promise as potential platforms in which to incorporate molecular catalysts. However, moving from a homogenous environment to catalysis in porous media, necessitates efficient mass and charge transport to the imbedded catalysts. Either diffusional charge transport or diffusion of substrate have the potential to limit the overall observed rate of product formation, if they are slower than the intrinsic rate of the catalytic reaction. This thesis seeks to examine the effect of diffusional mass and charge transport on molecular catalysis in MOFs.

    First, chemically driven water oxidation is examined using a molecular ruthenium catalyst covalently grafted in MIL(Cr)-101 (MIL = Materials Institute Lavoisier) (Chapter 3). A formal kinetic analysis using a steady-state reaction-diffusion model revealed the limitations incurred by mass transport of the chemical oxidant through the pores of the framework. Importantly, it was shown that interference from mass transport obscures turn-over frequencies, and intrinsic reaction kinetics are only measured under certain conditions. The following chapter entails a modified electrode with a UiO MOF film (UiO = University of Oslo)  containing a molecular catalyst, which is used for electrochemically mediated water oxidation (Chapter 4). The diffusional electron-hopping process is examined and discussed in the context of optimizing overall catalytic current densities. In Chapter 5, a new UiO-type MOF thin film is developed containing exclusively molecularly discrete naphthalene diimide linkers, which are redox-active. This can potentially provide charge transport pathways to imbedded catalysts in a two-component system. In addition, the electron-hopping diffusion coefficient was characterized in both non-aqueous and aqueous electrolytes. Lastly, the capacity of the charge-hopping process occurring in these redox-active MOF films to drive a model catalytic reaction is quantified (Chapter 6). Analysis by cyclic voltammetry is utilized to gain insight into the contributions to the current from the catalytic reaction, electron-hopping, substrate diffusion in the film, as well as mass transport in solution. 

    List of papers
    1. Formal water oxidation turnover frequencies from MIL-101(Cr) anchored Ru(bda) depend on oxidant concentration
    Open this publication in new window or tab >>Formal water oxidation turnover frequencies from MIL-101(Cr) anchored Ru(bda) depend on oxidant concentration
    Show others...
    2018 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 54, p. 7770-7773Article in journal (Refereed) Published
    Abstract [en]

    The molecular water oxidation catalyst [Ru(bda)(L)(2)] has been incorporated into pyridine-decorated MIL-101(Cr) metal-organic frameworks. The resulting MIL-101@Ru materials exhibit turnover frequencies (TOFs) up to ten times higher compared to the homogenous reference. An unusual dependence of the formal TOFs on oxidant concentration is observed that ultimately arises from differing amounts of catalysts in the MOF crystals being active.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2018
    National Category
    Inorganic Chemistry Materials Chemistry
    Identifiers
    urn:nbn:se:uu:diva-361265 (URN)10.1039/c8cc02300j (DOI)000438237700009 ()29926035 (PubMedID)
    Funder
    Swedish Research CouncilSwedish Energy AgencyKnut and Alice Wallenberg FoundationEU, European Research Council, ERC-CoG2015-681895_MOFcat
    Note

    De två första författarna delar förstaförfattarskapet.

    Available from: 2018-10-11 Created: 2018-10-11 Last updated: 2020-01-13Bibliographically approved
    2. Electrocatalytic water oxidation by a molecular catalyst incorporated into a metal-organic framework thin film
    Open this publication in new window or tab >>Electrocatalytic water oxidation by a molecular catalyst incorporated into a metal-organic framework thin film
    2017 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 46, no 5, p. 1382-1388Article in journal (Refereed) Published
    Abstract [en]

    A molecular water oxidation catalyst, [Ru(tpy)(dcbpy)(OH2)](ClO4)(2) (tpy = 2,2': 6',2''-terpyridine, dcbpy = 2,2'-bipyridine- 5,5'-dicarboxylic acid) [1], has been incorporated into FTO-grown thin films of UiO-67 (UiO = University of Oslo), by post-synthetic ligand exchange. Cyclic voltammograms (0.1 M borate buffer at pH = 8.4) of the resulting UiO67-[RuOH2]@ FTO show a reversible wave associated with the Ru-III/II couple in the anodic scan, followed by a large current response that arises from electrocatalytic water oxidation beyond 1.1 V vs. Ag/AgCl. Water oxidation can be observed at an applied potential of 1.5 V over the timescale of hours with a current density of 11.5 mu A cm(-2). Oxygen evolution was quantified in situ over the course of the experiment, and the Faradaic efficiency was calculated as 82%. Importantly, the molecular integrity of [1] during electrocatalytic water oxidation is maintained even on the timescale of hours under turnover conditions and applied voltage, as evidenced by the persistence of the wave associated with the Ru-III/II couple in the CV. This experiment highlights the capability of metal organic frameworks like UiO-67 to stabilize the molecular structure of catalysts that are prone to form higher clusters in homogenous phase.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2017
    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-319681 (URN)10.1039/c6dt03718frsc.li/dalton (DOI)000395442700005 ()27845800 (PubMedID)
    Funder
    Swedish Research CouncilSwedish Energy AgencyKnut and Alice Wallenberg Foundation
    Available from: 2017-04-07 Created: 2017-04-07 Last updated: 2020-01-13Bibliographically approved
    3. Development of a UiO-Type Thin Film Electrocatalysis Platform with Redox-Active Linkers
    Open this publication in new window or tab >>Development of a UiO-Type Thin Film Electrocatalysis Platform with Redox-Active Linkers
    Show others...
    2018 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, no 8, p. 2985-2994Article in journal (Refereed) Published
    Abstract [en]

    Metal–organic frameworks (MOFs) as electrocatalysis scaffolds are appealing due to the large concentration of catalytic units that can be assembled in three dimensions. To harness the full potential of these materials, charge transport to the redox catalysts within the MOF has to be ensured. Herein, we report the first electroactive MOF with the UiO/PIZOF topology (Zr(dcphOH-NDI)), i.e., one of the most widely used MOFs for catalyst incorporation, by using redox-active naphthalene diimide-based linkers (dcphOH-NDI). Hydroxyl groups were included on the dcphOH-NDI linker to facilitate proton transport through the material. Potentiometric titrations of Zr(dcphOH-NDI) show the proton-responsive behavior via the −OH groups on the linkers and the bridging Zr-μ3-OH of the secondary building units with pKa values of 6.10 and 3.45, respectively. When grown directly onto transparent conductive fluorine-doped tin oxide (FTO), 1 μm thin films of Zr(dcphOH-NDI)@FTO could be achieved. Zr(dcphOH-NDI)@FTO displays reversible electrochromic behavior as a result of the sequential one-electron reductions of the redox-active NDI linkers. Importantly, 97% of the NDI sites are electrochemically active at applied potentials. Charge propagation through the thin film proceeds through a linker-to-linker hopping mechanism that is charge-balanced by electrolyte transport, giving rise to cyclic voltammograms of the thin films that show characteristics of a diffusion-controlled process. The equivalent diffusion coefficient, De, that contains contributions from both phenomena was measured directly by UV/vis spectroelectrochemistry. Using KPF6 as electrolyte, De was determined to be De(KPF6) = (5.4 ± 1.1) × 10–11 cm2 s–1, while an increase in countercation size to n-Bu4N+ led to a significant decrease of De by about 1 order of magnitude (De(n-Bu4NPF6) = (4.0 ± 2.5) × 10–12 cm2 s–1).

    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-351270 (URN)10.1021/jacs.7b13077 (DOI)000426617700044 ()29421875 (PubMedID)
    Funder
    Swedish Research Council
    Available from: 2018-06-04 Created: 2018-06-04 Last updated: 2020-01-13Bibliographically approved
    4. Analyzing Charge Extraction From an Electroactive MOF Film to a Redox Couple in Solution as a Model for Catalytic Reactions
    Open this publication in new window or tab >>Analyzing Charge Extraction From an Electroactive MOF Film to a Redox Couple in Solution as a Model for Catalytic Reactions
    (English)Manuscript (preprint) (Other academic)
    National Category
    Inorganic Chemistry Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-402205 (URN)
    Available from: 2020-01-13 Created: 2020-01-13 Last updated: 2020-01-13
  • 9.
    Johnson, Ben A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Agarwala, Hemlata
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Analyzing Charge Extraction From an Electroactive MOF Film to a Redox Couple in Solution as a Model for Catalytic ReactionsManuscript (preprint) (Other academic)
  • 10.
    Kovacs, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Kiraev, Salauat
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Phipps, Dulcie
    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, Synthetic Molecular Chemistry.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Eu(III) and Tb(III) Complexes of Octa- and Nonadentate Macrocyclic Ligands Carrying Azide, Alkyne, and Ester Reactive Groups2020In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 59, no 1, p. 106-117Article in journal (Refereed)
    Abstract [en]

    Azide- and allcyne-functionalized bioconjugable luminescent lanthanide complexes are reported. Reactive handles were introduced into the complexes by the late-stage modification of a methylenecarboxylic acid antenna pendent group. Tb and Eu quantum yields (11-13% and 3.4-3.6%, respectively) were not greatly affected by the presence of the azide or the alkyne compared to the parent complex (Phi(Tb) = 10%, Phi(Eu) = 2.8%). Two avenues were explored for improving the luminescence of the lanthanide (Ln) complexes: (1) attaching the antenna through a tertiary amide linker and (2) replacing a monodentate carboxylate ligand with a bidentate pyridylcarboxylate donor, which yielded a nonadentate ligand that could saturate the lanthanide coordination sphere and eliminate the quenching metal-bound water molecule that was present in the octadentate complexes. The combination of both approaches yielded Eu and Tb emitters with 5.8% and 46% quantum yields. For the Eu complex, this value was the same as Phi(Eu) in the octadentate parent complex. We attribute this to increased photoinduced electron transfer quenching in the nonadentate species, which compensates for the reduced O-H quenching.

  • 11.
    Liu, Tianfei
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tyburski, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Wang, Shihuai
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Fernandez-Teran, Ricardo
    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, Synthetic Molecular Chemistry.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Elucidating Proton-Coupled Electron Transfer Mechanisms of Metal Hydrides with Free Energy- and Pressure-Dependent Kinetics2019In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 141, no 43, p. 17245-17259Article in journal (Refereed)
    Abstract [en]

    Proton-coupled electron transfer (PCET) was studied in a series of tungsten hydride complexes with pendant pyridyl arms ([(PyCH2Cp)WH(CO)(3)], PyCH2Cp = pyridyl methyl cyclopentadienyl), triggered by laser flash-generated Ru-III-tris-bipyridine oxidants, in acetonitrile solution. The free energy dependence of the rate constant and the kinetic isotope effects (KIEs) showed that the PCET mechanism could be switched between concerted and the two stepwise PCET mechanisms (electron-first or proton-first) in a predictable fashion. Straightforward and general guidelines for how the relative rates of the different mechanisms depend on oxidant and base are presented. The rate of the concerted reaction should depend symmetrically on changes in oxidant and base strength, that is on the overall Delta G(PCET)(0), and we argue that an "asynchronous" behavior would not be consistent with a model where the electron and proton tunnel from a common transition state. The observed rate constants and KIEs were examined as a function of hydrostatic pressure (1-2000 bar) and were found to exhibit qualitatively different dependence on pressure for different PCET mechanisms. This is discussed in terms of different volume profiles of the PCET mechanisms as well as enhanced proton tunneling for the concerted mechanism. The results allowed for assignment of the main mechanism operating in the different cases, which is one of the critical questions in PCET research. They also show how the rate of a PCET reaction will be affected very differently by changes of oxidant and base strength, depending on which mechanism dominates. This is of fundamental interest as well as of practical importance for rational design of, for example, catalysts for fuel cells and solar fuel formation, which operate in steps of PCET reactions. The mechanistic richness shown by this system illustrates that the specific mechanism is not intrinsic to a specific synthetic catalyst or enzyme active site but depends on the reaction conditions.

  • 12.
    Materna, Kelly L.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Lalaoui, Noémie
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Laureanti, Joseph A.
    Pacific Northwest Natl Lab, POB 999, Richland, WA 99352 USA.
    Walsh, Aaron P.
    Ferro Corp, Penn Yan, NY 14527 USA.
    Pettersson-Rimgard, Belinda
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Thapper, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Shaw, Wendy J.
    Pacific Northwest Natl Lab, POB 999, Richland, WA 99352 USA.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Using Surface Amide Couplings to Assemble Photocathodes for Solar Fuel Production Applications2020In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 4, p. 4501-4509Article in journal (Refereed)
    Abstract [en]

    A facile surface amide-coupling method was examined to attach dye and catalyst molecules to silatrane-decorated NiO electrodes. Using this method, electrodes with a push-pull dye were assembled and characterized by photoelectrochemistry and transient absorption spectroscopy. The dye-sensitized electrodes exhibited hole injection into NiO and good photoelectrochemical stability in water, highlighting the stability of the silatrane anchoring group and the amide linkage. The amide-coupling protocol was further applied to electrodes that contain a molecular proton reduction catalyst for use in photocathode architectures. Evidence for catalyst reduction was observed during photoelectrochemical measurements and via photocathodes.

  • 13.
    McCarthy, Brian D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Beiler, Anna M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Johnson, Ben A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Liseev, Timofey
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Castner, Ashleigh T.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Analysis of electrocatalytic metal-organic frameworks2020In: Coordination chemistry reviews, ISSN 0010-8545, E-ISSN 1873-3840, Vol. 406, article id 213137Article, review/survey (Refereed)
    Abstract [en]

    The electrochemical analysis of molecular catalysts for the conversion of bulk feedstocks into energy-rich clean fuels has seen dramatic advances in the last decade. More recently, increased attention has focused on the characterization of metal-organic frameworks (MOFs) containing well-defined redox and catalytically active sites, with the overall goal to develop structurally stable materials that are industrially relevant for large-scale solar fuel syntheses. Successful electrochemical analysis of such materials draws heavily on well-established homogeneous techniques, yet the nature of solid materials presents additional challenges. In this tutorial-style review, we cover the basics of electrochemical analysis of electroactive MOFs, including considerations of bulk stability, methods of attaching MOFs to electrodes, interpreting fundamental electrochemical data, and finally electrocatalytic kinetic characterization. We conclude with a perspective of some of the prospects and challenges in the field of electrocatalytic MOFs. 

  • 14.
    McCarthy, Brian D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Liseev, Timofey
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Beiler, Anna M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Materna, Kelly L.
    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, Synthetic Molecular Chemistry.
    Facile Orientational Control of M2L2P SURMOFs on < 100 > Silicon Substrates and Growth Mechanism Insights for Defective MOFs2019In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 41, p. 38294-38302Article in journal (Refereed)
    Abstract [en]

    Layer-by-layer growth of Cu-2(bdc)(2)(dabco) surface-mounted metal organic frameworks (SURMOFs) was investigated on silicon wafers treated with different surface anchoring molecules. Well-oriented growth along the [100] and [001] directions could be achieved with simple protocols: growth along the [100] direction was achieved by substrate pretreatment with 80 degrees C piranha, while growth along the [001] direction was enabled by only rinsing silicon with absolute ethanol. Growth along the [001] direction produced more homogeneous SURMOF films. Optimization to enhance [001]-preferred orientation growth revealed that small changes in the SURMOF growth sequence (the number of rinse steps and linker concentrations) have a noticeable impact on the final film quality and the number of misaligned crystals. This new straightforward protocol was used to successfully grow other layer pillar-type SURMOFs, including the growth of Cu-2(bdc)(2)(bipy) with simultaneous suppression of framework interpenetration.

  • 15.
    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 University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Expansion of the scope of alkylboryl-bridged N -> B-ladder boranes: new substituents and alternative substrates2019In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 48, no 27, p. 10298-10312Article in journal (Refereed)
    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.

  • 16.
    Queyriaux, Nicolas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström. CNRS, LCC, F-31077 Toulouse, France.
    Swords, Wesley B.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Agarwata, Hemtata
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Johnson, Ben A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Mechanistic insights on the non-innocent role of electron donors: reversible photocapture of CO2 by Ru-II-polypyridyl complexes2019In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 48, no 45, p. 16894-16898Article in journal (Refereed)
    Abstract [en]

    The ability of [Ru-II((t)Butpy)(dmbpy)(MeCN)](2+) (1-MeCN) to capture CO2, with the assistance of triethanolamine (TEOA), has been assessed under photocatalytically-relevant conditions. The photolability of 1-MeCN has proven essential to generate a series of intermediates which only differ by the nature of their monodentate ligand. In DMF, ligand photoexchange of 1-MeCN to give [Ru-II((t)Butpy)(dmbpy)(DMF)](2+) (1-DMF) proceeds smoothly with a quantum yield of 0.011. However, in the presence of TEOA, this process was disrupted, leading to the formation of a mixture of 1-DMF and [Ru-II((t)Butpy)(dmbpy)(TEOA)](+) (1-TEOA). An equilibrium constant of 3 was determined. Interestingly, 1-TEOA demonstrated an ability to reversibly catch and release CO2 making it a potentially crucial intermediate towards CO2 reduction.

  • 17.
    Roy, Souvik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Huang, Zhehao
    Stockholm Univ, Berzelii Ctr EXSELENT Porous Mat, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.
    Bhunia, Asamanjoy
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Castner, Ashleigh
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Gupta, Arvind Kumar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Zou, Xiaodong
    Stockholm Univ, Berzelii Ctr EXSELENT Porous Mat, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Electrocatalytic Hydrogen Evolution from a Cobaloxime-Based Metal-Organic Framework Thin Film2019In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 141, no 40, p. 15942-15950Article in journal (Refereed)
    Abstract [en]

    Molecular hydrogen evolution catalysts (HECs) are synthetically tunable and often exhibit high activity, but they are also hampered by stability concerns and practical limitations associated with their use in the homogeneous phase. Their incorporation as integral linker units in metal-organic frameworks (MOFs) can remedy these shortcomings. Moreover, the extended three-dimensional structure of MOFs gives rise to high catalyst loadings per geometric surface area. Herein, we report a new MOF that exclusively consists of cobaloximes, a widely studied HEC, that act as metallo-linkers between hexanuclear zirconium clusters. When grown on conducting substrates and under applied reductive potential, the cobaloxime linkers promote electron transport through the film as well as function as molecular HECs. The obtained turnover numbers are orders of magnitude higher than those of any other comparable cobaloxime system, and the molecular integrity of the cobaloxime catalysts is maintained for at least 18 h of electrocatalysis. Being one of the very few hydrogen evolving electrocatalytic MOFs based on a redox-active metallo-linker, this work explores uncharted terrain for greater catalyst pathways.

  • 18.
    Shameem, Muhammad Anwar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Low-Coordinate Organopnictogens: Synthesis and Optoelectronic properties2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis work is based on the development of novel organopnictogen compounds and the exploration of their potential applications in organic electronics. In particular, incorporation of phosphorus and arsenic into π-conjugated systems is known to modify the optoelectronic properties.

    The first chapter of this thesis is fully devoted to the development of a metal-free synthetic route that allows direct, sequential and stereoselective alkynylation of C,C-dibromophosphaalkenes. The subsequent unusual reactivity of thus synthesized C-mono and C,C-diacetylenicphosphaalkenes with terminal acetylenes afforded highly substituted 1-phoshpha-1,3-butadienes heavier analogue of all carbon 1,3-butadiene motifs. Optimization of the reaction condition favored exclusively the formation of 1-phospha-1,3-butadienes. Unveiling the unique cyclization of the 3-yne 1-phospha-1,3-butadiene gave highly substituted phosphole derivatives. Further, it has been experimentally shown that the P=C unit is essential for this rare cyclization and rearrangement to give π-conjugated phosphole derivatives.

    The second chapter of this thesis work deals with incorporation of P/As in the form of phosphinidene and or arsinidene units as an exocyclic substituent at the bridge of the fused rigid cyclpentadithiophenes (p-CPDT) core. Furthermore, it demonstrates how this chemical modification at the bridgehead position selectively lowers the LUMO level. At a later stage, substitutions at α and α` positions of the central CPDT core was used to modify the HOMO level without further affecting the LUMO level. We also performed DFT calculations on these phosphinide/arsinidene p-CPDT derivatives to theoretical evaluate the impact of P and or As incorporation. The phosphinidene/arsinidene p-CPDT derivatives were fully characterized using electrochemical and optical spectroscopic techniques including transient absorption spectroscopy. Additionally, the arsinidene-p-CPDT were electrochemically polymerized, and the resultant polymer film was characterized by means of SEM and EDX.

    The last chapter of this research work is dealing with the exploration and functionalization of open-ended small fragments of fullerene-C60 such as sumanene and truxene. Functionalisation of these motifs was achieved via the introduction of pnictogens (P/As), either in the form of phosphinidene/arsinidene or as heteroles. The optoelectronic spectra of the unprecedented pnictinidenotruxene exhibited significantly redshift absorption and three fully reversible reduction events upon electrochemical reduction.

    List of papers
    1. Direct, Sequential, and Stereoselective Alkynylation of C,C-Dibromophosphaalkenes
    Open this publication in new window or tab >>Direct, Sequential, and Stereoselective Alkynylation of C,C-Dibromophosphaalkenes
    Show others...
    2016 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 22, no 30, p. 10614-10619Article in journal (Refereed) Published
    Abstract [en]

    The first direct alkynylation of C,C-dibromophosphaalkenes by a reaction with sulfonylacetylenes is reported. Alkynylation proceeds selectively in the trans position relative to the P substituent to afford bromoethynylphosphaalkenes. Owing to the absence of transition metals in the procedure, the previously observed conversion of dibromophosphaalkenes into phosphaalkynes through the phosphorus analog of the Fritsch-Buttenberg-Wiechell rearrangement is thus suppressed. The bromoethynylphosphaalkenes can subsequently be converted to C,C-diacetylenic, cross-conjugated phosphaalkenes by following a Sonogashira coupling protocol in good overall yields. By using the newly described method, full control over the stereochemistry at the P=C double bond is achieved. The substrate scope of this reaction is demonstrated for different dibromophosphaalkenes as well as different sulfonylacetylenes.

    Keywords
    alkynylation, cross-conjugation, phosphaalkenes, Sonogashira coupling, sulfonyl coupling
    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-302705 (URN)10.1002/chem.201601955 (DOI)000380273300043 ()27310813 (PubMedID)
    External cooperation:
    Funder
    Swedish Research CouncilCarl Tryggers foundation
    Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-01-18Bibliographically approved
    2. Highly branched 2,3-diyne-1-phospha-1,3-butadiene motifs via Pd/Cu mediated alkynyl addition
    Open this publication in new window or tab >>Highly branched 2,3-diyne-1-phospha-1,3-butadiene motifs via Pd/Cu mediated alkynyl addition
    (English)Manuscript (preprint) (Other academic)
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-373905 (URN)
    Available from: 2019-01-17 Created: 2019-01-17 Last updated: 2019-01-18
    3. Synthesis and Characterization of Cyclopentadithiophene Heterofulvenes: Design Tools for Light-Activated Processes
    Open this publication in new window or tab >>Synthesis and Characterization of Cyclopentadithiophene Heterofulvenes: Design Tools for Light-Activated Processes
    Show others...
    2017 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, no 24, p. 5673-5677Article in journal (Refereed) Published
    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.

    Place, publisher, year, edition, pages
    WILEY-V C H VERLAG GMBH, 2017
    Keywords
    arsaalkene, electrochemistry, main group elements, phosphaalkene, pnictogens, time-resolved spectroscopy
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-322721 (URN)10.1002/chem.201700917 (DOI)000400044400006 ()28248442 (PubMedID)
    Funder
    Swedish Research Council, 2013-4763Knut and Alice Wallenberg FoundationÅForsk (Ångpanneföreningen's Foundation for Research and Development)
    Available from: 2017-05-29 Created: 2017-05-29 Last updated: 2019-01-18Bibliographically approved
  • 19.
    Toldo, Josene
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    El Bakouri, Ouissam
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Sola, Miquel
    Univ Girona, IQCC, C M Aurelia Capmany 69, Girona 17003, Spain;Univ Girona, Dept Quim, C M Aurelia Capmany 69, Girona 17003, Spain.
    Norrby, Per-Ola
    AstraZeneca, Early Prod Dev, Pharmaceut Sci, IMED Biotech Unit, Pepparedsleden 1, S-43183 Molndal, Sweden.
    Ottosson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Is Excited-State Aromaticity a Driving Force for Planarization of Dibenzannelated 8 Π-Electron Heterocycles?2019In: CHEMPLUSCHEM, ISSN 2192-6506, Vol. 84, no 6, p. 712-721Article in journal (Refereed)
    Abstract [en]

    Compounds with dibenzannelated heterocycles with eight pi-electrons are found in a range of applications. These molecules often adopt a bent structure in the ground state (S-0) but can become planar in the first excited states (S-1 and T-1) because of the cyclically conjugated 4n pi central ring, which fulfils the requirements for excited state aromaticity. We report on a quantum chemical investigation of the aromatic character in the S-1 and T-1 states of dibenzannelated seven- and six-membered heterocycles with one, two, or three heteroatoms in the 8 pi-electron ring. These states could have pi pi* or n pi* character. We find that compounds with one or two heteroatoms in the central ring have pi pi* states as their S-1 and T-1 states. They are to a significant degree influenced by excited state aromaticity, and their optimal structures are planar or nearly planar. Among the heteroatoms, nitrogen provides for the strongest excited state aromaticity whereas oxygen provides for the weakest, following the established trend of the S-0 state. Yet, dibenzannelated seven-membered-ring compounds with N=N bonds have non-aromatic n pi* states with strongly puckered structures as their S-1 and T-1 states.

  • 20.
    Vanderkooy, Alan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Gupta, Arvind Kumar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Foldes, Tamas
    Hungarian Acad Sci, Inst Organ Chem, Res Ctr Nat Sci, Magyar Tudosok Korutja 2, H-1117 Budapest, Hungary;Kings Coll London, Dept Chem, London SE1 1DB, England.
    Lindblad, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Papai, Imre
    Hungarian Acad Sci, Inst Organ Chem, Res Ctr Nat Sci, Magyar Tudosok Korutja 2, H-1117 Budapest, Hungary.
    Erdélyi, Máté
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Halogen Bonding Helicates Encompassing Iodonium Cations2019In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 58, no 27, p. 9012-9016Article in journal (Refereed)
    Abstract [en]

    The first halonium-ion-based helices were designed and synthesized using oligo-aryl/pyridylene-ethynylene backbones that fold around reactive iodonium ions. Halogen bonding interactions stabilize the iodonium ions within the helices. Remarkably, the distance between two iodonium ions within a helix is shorter than the sum of their van der Waals radii. The helical conformations were characterized by X-ray crystallography in the solid state, by NMR spectroscopy in solution and corroborated by DFT calculations. The helical complexes possess potential synthetic utility, as demonstrated by their ability to induce iodocyclization of 4-penten-1-ol.

  • 21.
    Wang, Shihuai
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Pullen, Sonja
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. TU Dortmund Univ, Fac Chem & Chem Biol, Otto Hahn Str 6, D-44227 Dortmund, Germany.
    Weippert, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Liu, Tianfei
    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, Synthetic Molecular Chemistry.
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Direct Spectroscopic Detection of Key Intermediates and Turnover Process in Catalytic H2 Formation by a Biomimetic Diiron Catalyst2019In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 25, no 47, p. 11135-11140Article in journal (Refereed)
    Abstract [en]

    [FeFe(Cl-2-bdt)(CO)(6)] (1; Cl-2-bdt=3,6-dichlorobenzene-1,2-dithiolate), inspired by the active site of FeFe-hydrogenase, shows a chemically reversible 2 e(-) reduction at -1.20 V versus the ferrocene/ferrocenium couple. The rigid and aromatic bdt bridging ligand lowers the reduction potential and stabilizes the reduced forms, compared with analogous complexes with aliphatic dithiolates; thus allowing details of the catalytic process to be characterized. Herein, time-resolved IR spectroscopy is used to provide kinetic and structural information on key catalytic intermediates. This includes the doubly reduced, protonated complex 1H(-), which has not been previously identified experimentally. In addition, the first direct spectroscopic observation of the turnover process for a molecular H-2 evolving catalyst is reported, allowing for straightforward determination of the turnover frequency.

  • 22.
    Wang, Vincent Cho-Chien
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johnson, Ben A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Interpreting the Electrocatalytic Voltammetry of Homogeneous Catalysts by the Foot of the Wave Analysis and Its Wider Implications2019In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 9, no 8, p. 7109-7123Article in journal (Refereed)
    Abstract [en]

    Mechanistic studies of electrocatalytic reactions play a crucial role in developing efficient electrocatalysts and solar-fuel devices. The foot of the wave analysis (FOWA) for cyclic voltammetry, recently developed by Saveant and Costentin, provides a powerful means to evaluate the performance of molecular electrocatalysts. However, there is a considerable amount of confusion in the community on how to interpret FOWA in multielectron electrochemical reactions. Herein, we further expand their earlier models from the Nernstian region to all scenarios (i.e., including non-Nernstian behavior) and systematically examine individual parameters, such as formal potentials and reaction rate constants, to explore deeper insights and limitations. Detailed analysis from in silico voltammograms based on different mechanistic models reveals characteristic features of FOWA traces for different kinetic phenomena, which is useful to diagnose kinetic profiles and elucidate the limits of FOWA. The lessons learned from these analyses are further used to reconcile the discrepancy of rate constants determined by FOWA versus other methods, such as time-resolved spectroscopy, for molecular electrocatalysts that catalyze proton reduction or the reduction of CO2 to CO. Such reconciliation demonstrates that electrochemical methods along with FOWA can serve as an alternative tool to determine kinetic information and probe mechanistic insights, which otherwise may be challenging and complicated to achieve by conventional methods. In addition, general guidelines and warnings are also presented to avoid potential errors or mishandling when using FOWA.

  • 23.
    Wu, Chia-Hua
    et al.
    Univ Houston, Dept Chem, Univ Pk, Houston, TX 77004 USA.
    Karas, Lucas José
    Univ Houston, Dept Chem, Univ Pk, Houston, TX 77004 USA.
    Ottosson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Wu, Judy I-Chia
    Univ Houston, Dept Chem, Univ Pk, Houston, TX 77004 USA.
    Excited-state proton transfer relieves antiaromaticity in molecules2019In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 116, no 41, p. 20303-20308Article in journal (Refereed)
    Abstract [en]

    Baird’s rule explains why and when excited-state proton transfer (ESPT) reactions happen in organic compounds. Bifunctional compounds that are [4n + 2] π-aromatic in the ground state, become [4n + 2] π-antiaromatic in the first 1ππ* states, and proton transfer (either inter- or intramolecularly) helps relieve excited-state antiaromaticity. Computed nucleus-independent chemical shifts (NICS) for several ESPT examples (including excited-state intramolecular proton transfers (ESIPT), biprotonic transfers, dynamic catalyzed transfers, and proton relay transfers) document the important role of excited-state antiaromaticity. o-Salicylic acid undergoes ESPT only in the “antiaromatic” S1 (1ππ*) state, but not in the “aromatic” S2 (1ππ*) state. Stokes’ shifts of structurally related compounds [e.g., derivatives of 2-(2-hydroxyphenyl)benzoxazole and hydrogen-bonded complexes of 2-aminopyridine with protic substrates] vary depending on the antiaromaticity of the photoinduced tautomers. Remarkably, Baird’s rule predicts the effect of light on hydrogen bond strengths; hydrogen bonds that enhance (and reduce) excited-state antiaromaticity in compounds become weakened (and strengthened) upon photoexcitation.

  • 24.
    Xiong, Ruisheng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Arkhypchuk, Anna I.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Attempted syntheses of N-confused hydroporphyrins through modified Lindsey routes2019In: Journal of Porphyrins and Phthalocyanines, ISSN 1088-4246, E-ISSN 1099-1409, Vol. 23, no 4-5, p. 589-598Article in journal (Refereed)
    Abstract [en]

    Unlike N-confused porphyrins which are well-known and extensively studied tetrapyrroles, N-confused hydroporphyrins are almost unknown, largely because so far they have resisted attempts at rational synthesis. Here, we report our efforts towards the total synthesis of N-confused hydroporphyrins. We have prepared N-confused building blocks analogous to the non-N-confused substrates in the Lindsey synthesis of sparsely substituted chlorins. We have systematically flipped the A, B and C pyrrole rings in the dipyrrolic precursors of the target N-confused macrocycles, preparing in total an N-confused "Western half' (tetrahydrodipyrrin) and two N-confused "Eastern halves" (brominated formyldipyrromethanes). These were subjected to a range of cyclization conditions. While we successfully isolated and identified three macrocyclic products, none of these proved to be the desired N-confused hydroporphyrin.

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