Harry B. Gray

Pennsylvania State University, University Park, Maryland, United States

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Publications (918)2013.92 Total impact

  • John J. Kozak · Harry B. Gray · Roberto A. Garza-López ·
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    ABSTRACT: We have developed a model to study the role of geometrical factors in influencing the early stages of unfolding in three cytochromes: cyt c', cyt c-b562 and cyt c. Each stage in unfolding is quantified by the spatial extension λ̂i of n-residue segments, and by their angular extension 〈βn〉. Similarities and differences between and among the three cytochromes in the unfolding of helical and non-helical regions can be determined by analyzing the data for each signature separately. Definite conclusions can be drawn when spatial and angular changes are considered in tandem. To facilitate comparisons, we present graphical portraits of the three cytochromes at the same stage of unfolding, and in relation to their native state structures. We also display specific segments at different stages of unfolding to illustrate differences in stability of defined domains thereby allowing us to make specific predictions on the unfolding of corresponding internal and terminal helices in cyt c' and cyt c-b562. Our work accords with an earlier experimental report on the presence and persistence of a hydrophobic core in cyt c.
    Journal of inorganic biochemistry 11/2015; 155. DOI:10.1016/j.jinorgbio.2015.11.001 · 3.44 Impact Factor
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    Julia G Lyubovitsky · Harry B Gray · Jay R Winkler ·

  • Jay R. Winkler · Harry B. Gray ·
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    ABSTRACT: Biological electron transfers often occur between metal-containing cofactors that are separated by very large molecular distances. Employing photosensitizer-modified iron and copper proteins, we have shown that single-step electron tunneling can occur on nanosecond to microsecond timescales at distances between 15 and 20 Å. We also have shown that charge transport can occur over even longer distances by hole hopping (multistep tunneling) through intervening tyrosines and tryptophans. In this perspective, we advance the hypothesis that such hole hopping through Tyr/Trp chains could protect oxygenase, dioxygenase, and peroxidase enzymes from oxidative damage. In support of this view, by examining the structures of P450 (CYP102A) and 2OG-Fe (TauD) enzymes, we have identified candidate Tyr/Trp chains that could transfer holes from uncoupled high-potential intermediates to reductants in contact with protein surface sites.
    Quarterly Reviews of Biophysics 11/2015; 48(04):411-420. DOI:10.1017/S0033583515000062 · 7.81 Impact Factor
  • Kara L. Bren · Richard Eisenberg · Harry B. Gray ·
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    ABSTRACT: Two articles published by Pauling and Coryell in PNAS nearly 80 years ago described in detail the magnetic properties of oxy- and deoxyhemoglobin, as well as those of closely related compounds containing hemes. Their measurements revealed a large difference in magnetism between oxygenated and deoxygenated forms of the protein and, along with consideration of the observed diamagnetism of the carbonmonoxy derivative, led to an electronic structural formulation of oxyhemoglobin. The key role of hemoglobin as the main oxygen carrier in mammalian blood had been established earlier, and its allosteric behavior had been described in the 1920s. The Pauling-Coryell articles on hemoglobin represent truly seminal contributions to the field of bioinorganic chemistry because they are the first to make connections between active site electronic structure and the function of a metalloprotein.
    Proceedings of the National Academy of Sciences 10/2015; 112(43):13123-13127. DOI:10.1073/pnas.1515704112 · 9.67 Impact Factor
  • Harry B Gray · Jay R Winkler ·
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    ABSTRACT: Living organisms have adapted to atmospheric dioxygen by exploiting its oxidizing power while protecting themselves against toxic side effects. Reactive oxygen and nitrogen species formed during oxidative stress, as well as high-potential reactive intermediates formed during enzymatic catalysis, could rapidly and irreversibly damage polypeptides were protective mechanisms not available. Chains of redox-active tyrosine and tryptophan residues can transport potentially damaging oxidizing equivalents (holes) away from fragile active sites and toward protein surfaces where they can be scavenged by cellular reductants. Precise positioning of these chains is required to provide effective protection without inhibiting normal function. A search of the structural database reveals that about one third of all proteins contain Tyr/Trp chains composed of three or more residues. Although these chains are distributed among all enzyme classes, they appear with greatest frequency in the oxidoreductases and hydrolases. Consistent with a redox-protective role, approximately half of the dioxygen-using oxidoreductases have Tyr/Trp chain lengths ≥3 residues. Among the hydrolases, long Tyr/Trp chains appear almost exclusively in the glycoside hydrolases. These chains likely are important for substrate binding and positioning, but a secondary redox role also is a possibility.
    Proceedings of the National Academy of Sciences 09/2015; 112(35):10920-5. DOI:10.1073/pnas.1512704112 · 9.67 Impact Factor
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    ABSTRACT: W(CNAryl)6 complexes containing 2,6-diisopropylphenyl isocyanide (CNdipp) are powerful photoreductants with strongly emissive long-lived excited states. These properties are enhanced upon appending another aryl ring, e.g., W(CNdippPh(OMe2))6; CNdippPh(OMe2) = 4-(3,5-dimethoxyphenyl)-2,6-diisopropylphenylisocyanide ( Sattler et al. J. Am. Chem. Soc. 2015 , 137 , 1198 - 1205 ). Electronic transitions and low-lying excited states of these complexes were investigated by time-dependent density functional theory (TDDFT); the lowest triplet state was characterized by time-resolved infrared spectroscopy (TRIR) supported by density functional theory (DFT). The intense absorption band of W(CNdipp)6 at 460 nm and that of W(CNdippPh(OMe2))6 at 500 nm originate from transitions of mixed ππ*(C≡N-C)/MLCT(W → Aryl) character, whereby W is depopulated by ca. 0.4 e(-) and the electron-density changes are predominantly localized along two equatorial molecular axes. The red shift and intensity rise on going from W(CNdipp)6 to W(CNdippPh(OMe2))6 are attributable to more extensive delocalization of the MLCT component. The complexes also exhibit absorptions in the 300-320 nm region, owing to W → C≡N MLCT transitions. Electronic absorptions in the spectrum of W(CNXy)6 (Xy = 2,6-dimethylphenyl), a complex with orthogonal aryl orientation, have similar characteristics, although shifted to higher energies. The relaxed lowest W(CNAryl)6 triplet state combines ππ* excitation of a trans pair of C≡N-C moieties with MLCT (0.21 e(-)) and ligand-to-ligand charge transfer (LLCT, 0.24-0.27 e(-)) from the other four CNAryl ligands to the axial aryl and, less, to C≡N groups; the spin density is localized along a single Aryl-N≡C-W-C≡N-Aryl axis. Delocalization of excited electron density on outer aryl rings in W(CNdippPh(OMe2))6 likely promotes photoinduced electron-transfer reactions to acceptor molecules. TRIR spectra show an intense broad bleach due to ν(C≡N), a prominent transient upshifted by 60-65 cm(-1), and a weak down-shifted feature due to antisymmetric C≡N stretch along the axis of high spin density. The TRIR spectral pattern remains unchanged on the femtosecond-nanosecond time scale, indicating that intersystem crossing and electron-density localization are ultrafast (<100 fs).
    Inorganic Chemistry 08/2015; 54(17). DOI:10.1021/acs.inorgchem.5b01203 · 4.76 Impact Factor
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    ABSTRACT: An n+p-Si microwire array coupled with a two-layer catalyst film consisting of Ni–Mo nanopowder and TiO2 light-scattering nanoparticles has been used to simultaneously achieve high fill factors and light-limited photocurrent densities from photocathodes that produce H2(g) directly from sunlight and water. The TiO2 layer scattered light back into the Si microwire array, while optically obscuring the underlying Ni–Mo catalyst film. In turn, the Ni–Mo film had a mass loading sufficient to produce high catalytic activity, on a geometric area basis, for the hydrogen-evolution reaction. The best-performing microwire array devices prepared in this work exhibited short-circuit photocurrent densities of −14.3 mA cm−2, photovoltages of 420 mV, and a fill factor of 0.48 under 1 Sun of simulated solar illumination, whereas the equivalent planar Ni–Mo-coated Si device, without TiO2 scatterers, exhibited negligible photocurrent due to complete light blocking by the Ni–Mo catalyst layer.
    Energy & Environmental Science 08/2015; 8(10). DOI:10.1039/C5EE01076D · 20.52 Impact Factor
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    ABSTRACT: Water-soluble corroles with inherent fluorescence can form stable self-assemblies with tumor-targeted cell penetration proteins, and have been explored as agents for optical imaging and photosensitization of tumors in pre-clinical studies. However, the limited tissue-depth of excitation wavelengths limits their clinical applicability. To examine their utility in more clinically-relevant imaging and therapeutic modalities, here we have explored the use of corroles as contrast enhancing agents for magnetic resonance imaging (MRI), and evaluated their potential for tumor-selective delivery when encapsulated by a tumor-targeted polypeptide. We have found that a manganese-metallated corrole exhibits significant T1 relaxation shortening and MRI contrast enhancement that is blocked by particle formation in solution but yields considerable MRI contrast after tissue uptake. Cell entry but not low pH enables this. Additionally, the corrole elicited tumor-toxicity through the loss of mitochondrial membrane potential and cytoskeletal breakdown when delivered by the targeted polypeptide. The protein-corrole particle (which we call HerMn) exhibited improved therapeutic efficacy compared to current targeted therapies used in the clinic. Taken together with its tumor-preferential biodistribution, our findings indicate that HerMn can facilitate tumor-targeted toxicity after systemic delivery and tumor-selective MR imaging activatable by internalization. Copyright © 2015. Published by Elsevier B.V.
    Journal of Controlled Release 08/2015; 217. DOI:10.1016/j.jconrel.2015.08.046 · 7.71 Impact Factor
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    ABSTRACT: Corroles have been shown experimentally to cause cell cycle arrest, and there is some evidence that this might be attributed to an inhibitory effect of corroles on Heat shock protein 90 (Hsp90), which is known to play a vital role in cancer cell proliferation. In this study, we used molecular dynamics to examine the interaction of gallium corroles with Hsp90, and found that it can bind preferentially to the ATP-binding N-terminal site. We also found that structural variations of the corrole ring can influence the binding energies and affinities of the corrole to Hsp90. We predict that both the bis-carboxylated corrole (4-Ga) and a proposed 3,17-bis-sulfonated corrole (7-Ga) are promising alternatives to Ga(III) 5,10,15-tris(pentafluorophenyl)-2,17-bis(sulfonic acid)-corrole (1-Ga) as anti-cancer agents.
    Molecular BioSystems 07/2015; 11(11). DOI:10.1039/C5MB00352K · 3.21 Impact Factor
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    ABSTRACT: The electrocatalytic performance for hydrogen evolution has been evaluated for radial-junction n+p-Si microwire (MW) arrays with Pt or cobalt phosphide, CoP, nanoparticulate catalysts in contact with 0.50 M H2SO4(aq). The CoP-coated (2.0 mg cm-2) n+p-Si MW photocathodes were stable for over 12 h of continuous operation and produced an open-circuit photovoltage (Voc) of 0.48 V, a light-limited photocurrent density (Jph) of 17 mA cm-2, a fill factor (ff) of 0.24, and an ideal regenerative cell efficiency (ηIRC) of 1.9% under simulated 1 Sun illumination. Pt-coated (0.5 mg cm-2) n+p-Si MW-array photocathodes produced Voc = 0.44 V, Jph = 14 mA cm-2, ff = 0.46, and η = 2.9% under identical conditions. Thus, the MW geometry allows the fabrication of photocathodes entirely comprised of earth-abundant materials that exhibit performance comparable to that of devices that contain Pt.Keywords: silicon; cobalt phosphide; hydrogen evolution; platinum; microwires; solar fuel
    Journal of Physical Chemistry Letters 05/2015; 6(9):1679-1683. DOI:10.1021/acs.jpclett.5b00495 · 7.46 Impact Factor
  • Andrew K. Udit · Michael G. Hill · Harry B. Gray ·
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    ABSTRACT: This chapter reviews the efforts to develop catalytically competent P450 systems in which a simple electrode replaces NAD(P)H, and in some instances native reductase proteins, in the catalytic cycle. Notably, in evaluating the successes of P450 electrocatalytic methods, there is an important distinction to be made between mammalian and bacterial systems. While some mention of notable mammalian P450 electrocatalytic systems is made, the chapter focuses primarily on bacterial systems and specifically on the NADPH dependent flavocytochrome P450 from Bacillus megaterium (BM3). Harnessing P450 activity for in vitro applications may be most simply accomplished with electrochemical systems utilizing soluble mediators. Protein–surfactant film voltammetry has been widely used for studying the redox chemistry of P450s. Another striking aspect of P450 electrochemistry in surfactant films is the dramatic shift of the FeIII/II couple to positive potentials. Finally, mediated electrochemical P450 systems are perhaps the best bets for large-scale biocatalysis.
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    ABSTRACT: The mechanistic features of oligomerization and oxidative cyclization steps in the synthesis of tris(pentafluorophenyl)corrole (1) have been thoroughly studied. Separation of the intermediates by preparative HPLC and analysis by NMR spectroscopy and high resolution mass spectrometry allowed for the identification of product-forming intermediates and monitoring of undesired byproducts. Conditions for complete end-capping with pyrrole were optimized for improved yields of oligomers leading to the desired corrole 1. A yield of 84 % was achieved during oxidation of an isolated precursor; the overall yield of 1 was 17.0 %.
    European Journal of Organic Chemistry 04/2015; 2015(14). DOI:10.1002/ejoc.201500276 · 3.07 Impact Factor
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    ABSTRACT: Chemotherapy often involves broad-spectrum cytotoxic agents with many side effects and limited targeting. Corroles are a class of tetrapyrrolic macrocycles that exhibit differential cytostatic and cytotoxic properties in specific cell lines, depending on the identities of the chelated metal and functional groups. The unique behavior of functionalized corroles towards specific cell lines introduces the possibility of targeted chemotherapy. Many anticancer drugs are evaluated by their ability to inhibit RNA transcription. Here we present a step-by-step protocol for RNA transcription in the presence of known and potential inhibitors. The evaluation of the RNA products of the transcription reaction by gel electrophoresis and UV-Vis spectroscopy provides information on inhibitive properties of potential anticancer drug candidates and, with modifications to the assay, more about their mechanism of action. Little is known about the molecular mechanism of action of corrole cytotoxicity. In this experiment, we consider two corrole compounds: gallium(III) 5,10,15-(tris)pentafluorophenylcorrole (Ga(tpfc)) and freebase analogue 5,10,15-(tris)pentafluorophenylcorrole (tpfc). An RNA transcription assay was used to examine the inhibitive properties of the corroles. Five transcription reactions were prepared: DNA treated with Actinomycin D, triptolide, Ga(tpfc), tpfc at a [complex]:[template DNA base] ratio of 0.01, respectively, and an untreated control. The transcription reactions were analyzed after 4 hr using agarose gel electrophoresis and UV-Vis spectroscopy. There is clear inhibition by Ga(tpfc), Actinomycin D, and triptolide. This RNA transcription assay can be modified to provide more mechanistic detail by varying the concentrations of the anticancer complex, DNA, or polymerase enzyme, or by incubating the DNA or polymerase with the complexes prior to RNA transcription; these modifications would differentiate between an inhibition mechanism involving the DNA or the enzyme. Adding the complex after RNA transcription can be used to test whether the complexes degrade or hydrolyze the RNA. This assay can also be used to study additional anticancer candidates.
    Journal of Visualized Experiments 03/2015; 2015(97). DOI:10.3791/52355 · 1.33 Impact Factor
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    ABSTRACT: A scanning probe image of single-layer MoS2 trapping water on a mica surface is depicted on the left, with its corresponding photoluminescence image depicted on the right. The trapped water strongly quenches the fluorescence of single-layer MoS2 and distinctly affects its optical properties. The work by J. R. Heath and co-workers on page 2734 highlights the significance of the local chemical environment in determining the opto-electronic properties of 2D materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Advanced Materials 03/2015; 27(17). DOI:10.1002/adma.201500555 · 17.49 Impact Factor
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    ABSTRACT: [Pt2(μ-P2O5H2)4](4-) (Pt(pop)) and its perfluoroborated derivative [Pt2(μ-P2O5(BF2)2)4](4-) (Pt(pop-BF2)) are d(8)-d(8) complexes whose electronic excited states can drive reductions and oxidations of relatively inert substrates. We performed spin-orbit (SO) TDDFT calculations on these complexes that account for their absorption spectra across the entire UV-vis spectral region. The complexes exhibit both fluorescence and phosphorescence attributable, respectively, to singlet and triplet excited states of dσ*pσ origin. These features are energetically isolated from each other (∼7000 cm(-1) for (Pt(pop-BF2)) as well as from higher-lying states (5800 cm(-1)). The lowest (3)dσ*pσ state is split into three SO states by interactions with higher-lying singlet states with dπpσ and, to a lesser extent, pπpσ contributions. The spectroscopically allowed dσ*pσ SO state has ∼96% singlet character with small admixtures of higher triplets of partial dπpσ and pπpσ characters that also mix with (3)dσ*pσ, resulting in a second-order (1)dσ*pσ-(3)dσ*pσ SO interaction that facilitates intersystem crossing (ISC). All SO interactions involving the dσ*pσ states are weak because of large energy gaps to higher interacting states. The spectroscopically allowed dσ*pσ SO state is followed by a dense manifold of ligand-to-metal-metal charge transfer states, some with pπpσ (at lower energies) or dπpσ contributions (at higher energies). Spectroscopically active higher states are strongly spin-mixed. The electronic structure, state ordering, and relative energies are minimally perturbed when the calculation is performed at the optimized geometries of the (1)dσ*pσ and (3)dσ*pσ excited states (rather than the ground state). Results obtained for Pt(pop) are very similar, showing slightly smaller energy gaps and, possibly, an additional (1)dσ*pσ - (3)dσ*pσ second order SO interaction involving higher (1)dπpσ* states that could account in part for the much faster ISC. It also appears that (1)dσ*pσ → (3)dσ*pσ ISC requires a structural distortion that has a lower barrier for Pt(pop) than for the more rigid Pt(pop-BF2).
    Inorganic Chemistry 03/2015; 54(7). DOI:10.1021/acs.inorgchem.5b00063 · 4.76 Impact Factor
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    Jay R Winkler · Harry B Gray ·
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    ABSTRACT: Single-step electron tunnelling reactions can transport charges over distances of 15-20 Åin proteins. Longer-range transfer requires multi-step tunnelling processes along redox chains, often referred to as hopping. Long-range hopping via oxidized radicals of tryptophan and tyrosine, which has been identified in several natural enzymes, has been demonstrated in artificial constructs of the blue copper protein azurin. Tryptophan and tyrosine serve as hopping way stations in high-potential charge transport processes. It may be no coincidence that these two residues occur with greater-than-average frequency in O2- and H2O2-reactive enzymes. We suggest that appropriately placed tyrosine and/or tryptophan residues prevent damage from high-potential reactive intermediates by reduction followed by transfer of the oxidizing equivalent to less harmful sites or out of the protein altogether. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
    Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 03/2015; 373(2037). DOI:10.1098/rsta.2014.0178 · 2.15 Impact Factor
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    ABSTRACT: fac-[(L)Mn(CO)3]- , where L = bis alkyl-substituted bipyridine, catalyzes electrochemical reduction of CO2 to CO in the presence of trifluoroethanol (TFEH). Here we report the atomistic level mechanism of complete catalytic cycles for this reaction, using DFT methods (B3LYP-d3 with continuum solvation) to compute free energies of reaction and activation, as well as reduction potentials for all catalytically relevant elementary steps. In the catalytic cycle for CO formation, CO2 coordinates to fac-[(L)Mn(CO)3]- (1) (L = bpy), and the adduct (2) is protonated to form [(L)Mn(CO)3(CO2H)] (3). 3 reacts to form [(L)Mn(CO)4]0 (5) via one of two pathways: TFEH-mediated dehydroxylation to [(L)Mn(CO)4]+ (4), followed by one-electron reduction to 5; or, under more reducing potentials, one electron reduction to [(L)Mn(CO)3(CO2H)]- (3’), followed by dehydroxylation to 5. The latter pathway has a lower activation energy yielding higher reaction rates at higher overpotentials. Finally 5 is reduced upon CO dissociation to regenerate 1. The highly exergonic homoconjugation and carbonation of TFE- play a critical role in reaction thermodynamics and kinetics. Based on the analogous free energy surface for L = bipyrimidine (not yet studied experimentally), we predict the faster CO2 reduction pathway (via dehydroxylation of 3’ to 5) dominates even at zero overpotential, albeit at the expense of a somewhat higher kinetic barrier (by ca. 2 kcal mol-1). The various factors contributing to product selectivity (CO over H2) are discussed.
    ACS Catalysis 02/2015; 5(4):150216174835004. DOI:10.1021/cs501963v · 9.31 Impact Factor
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    ABSTRACT: Modular syntheses of oligoarylisocyanide ligands that are derivatives of 2,6-diisopropylphenyl isocyanide (CNdipp) have been developed; tungsten complexes incorporating these oligoarylisocyanide ligands exhibit intense metal-to-ligand charge-transfer visible absorptions that are red-shifted and more intense than those of the parent W(CNdipp)6 complex. Additionally, these W(CNAr)6 complexes have enhanced excited-state properties, including longer lifetimes and very high quantum yields. The decay kinetics of electronically excited W(CNAr)6 complexes (*W(CNAr)6) show solvent dependences; faster decay is observed in higher dielectric solvents. *W(CNAr)6 lifetimes are temperature dependent, suggestive of a strong coupling nonradiative decay mechanism that promotes repopulation of the ground state. Notably, *W(CNAr)6 complexes are exceptionally strong reductants: [W(CNAr)6](+)/*W(CNAr)6 potentials are more negative than -2.7 V vs [Cp2Fe](+)/Cp2Fe.
    Journal of the American Chemical Society 01/2015; 137(3). DOI:10.1021/ja510973h · 12.11 Impact Factor
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    ABSTRACT: Transient absorption decay rate constants (kobs) for reactions of electronically excited zinc tetraphenylporphyrin (3ZnTPP*) with triruthenium oxo-centered acetate-bridged clusters [Ru3(µ3-O)(µ-CH3CO2)6(CO)(L)]2(µ-pz), where pz = pyrazine and L = 4-cyanopyridine (cpy) (1), pyridine (py) (2), or 4-dimethylaminopyridine (dmap) (3), were obtained from nanosecond flash-quench spectroscopic data (quenching constants, kq, for 3ZnTPP*/1 - 3 are 3.0 × 109, 1.5 ×109, and 1.1 × 109 M-1s-1, respectively). Values of kq for reactions of 3ZnTPP* with 1 - 3 and Ru3(µ3-O)(µ-CH3CO2)6(CO)(L)2 [L = cpy (4), py (5), dmap (6)] monomeric analogues suggest that photoinduced electron transfer is the main pathway of excited-state decay; this mechanistic proposal is consistent with results from a photolysis control experiment, where growth of characteristic near-IR absorption bands attributable to reduced (mixed-valence) Ru-cluster products were observed.
    The Journal of Physical Chemistry B 12/2014; 119(24). DOI:10.1021/jp511213p · 3.30 Impact Factor
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    ABSTRACT: Bismuth vanadate is a promising photoanode material, but recent reports on undoped BiVO4 without sublayers and co-catalysts showed large variations in photocurrent generation. We addressed this issue by correlating photoelectrochemical performance with physical properties. We devised a novel anodic electrodeposition procedure with iodide added to the aqueous plating bath, which allowed us to prepare BiVO4 photoanodes with virtually identical thicknesses but different morphologies, and we could control surface Bi content. Morphologies were quantified from SEM images as distributions of crystallite areas and aspect-ratio-normalised diameters, and their statistical moments were derived. We could obtain clear photocurrent generation trends only from bivariate data analysis. Our experimental evidence suggests that a combination of low Bi/V ratio, small aspect-ratio-normalised diameters, and crystallites sizes that were small enough to provide efficient charge separation yet sufficiently large to prevent mass transport limitations led to highest photoelectrochemical performance.
    12/2014; 2(3). DOI:10.1039/C4MH00156G

Publication Stats

37k Citations
2,013.92 Total Impact Points


  • 1975-2015
    • Pennsylvania State University
      • • Department of Chemical Engineering
      • • Department of Chemistry
      University Park, Maryland, United States
  • 1970-2015
    • University of Illinois, Urbana-Champaign
      • Department of Chemistry
      Urbana, Illinois, United States
  • 1968-2015
    • California Institute of Technology
      • • Beckman Institute
      • • Division of Chemistry and Chemical Engineering
      • • Jet Propulsion Laboratory
      • • Arthur Amos Noyes Laboratory of Chemical Physics
      Pasadena, California, United States
  • 1988-2012
    • Technion - Israel Institute of Technology
      • Schulich Faculty of Chemistry
      H̱efa, Haifa, Israel
    • University of Pittsburgh
      • Department of Chemistry
      Pittsburgh, Pennsylvania, United States
  • 2011
    • Beckman Research Institute
      Duarte, California, United States
  • 2009
    • Lake Tahoe Community College
      South Lake Tahoe, California, United States
  • 2008
    • University of Bologna
      Bologna, Emilia-Romagna, Italy
  • 1987-2008
    • University of California, Los Angeles
      • Department of Chemistry and Biochemistry
      Los Ángeles, California, United States
  • 2007
    • Occidental College
      • Department of Chemistry
      Los Angeles, California, United States
  • 2006
    • University of Zurich
      • Institut für Anorganische Chemie
      Zürich, Zurich, Switzerland
  • 2005
    • The University of Arizona
      Tucson, Arizona, United States
  • 1981-2005
    • Stanford University
      • • Department of Biochemistry
      • • Department of Chemistry
      Palo Alto, California, United States
  • 2004
    • University of London
      Londinium, England, United Kingdom
  • 2003
    • Polytechnic University of Puerto Rico
      San Juan, San Juan, Puerto Rico
    • Iowa State University
      Ames, Iowa, United States
  • 1995-2003
    • University of Florence
      • Magnetic Resonance Center (CERM)
      Florens, Tuscany, Italy
  • 1962-2003
    • Northwestern University
      • Department of Cell and Molecular Biology
      Evanston, Illinois, United States
    • IT University of Copenhagen
      København, Capital Region, Denmark
  • 2002
    • Tel Aviv University
      Tell Afif, Tel Aviv, Israel
  • 1998
    • Wabash College
      • Chemistry
      کرافوردزویل، ایندیانا, Indiana, United States
    • Newcastle University
      • School of Chemistry
      Newcastle-on-Tyne, England, United Kingdom
  • 1997
    • University of Gothenburg
      Goeteborg, Västra Götaland, Sweden
  • 1987-1996
    • Los Alamos National Laboratory
      Los Alamos, California, United States
  • 1968-1996
    • Pasadena City College
      Pasadena, Texas, United States
  • 1990
    • Brookhaven National Laboratory
      • Chemistry Department
      New York, New York, United States
  • 1989
    • The Chinese University of Hong Kong
      • Department of Physics
      Hong Kong, Hong Kong
  • 1963-1989
    • Columbia University
      • Department of Chemistry
      New York, New York, United States
  • 1984
    • Chalmers University of Technology
      • Division of Chemical Physics
      Goeteborg, Västra Götaland, Sweden
    • University of California, Davis
      • Department of Chemistry
      Davis, California, United States
  • 1980
    • University of Toronto
      • Department of Chemistry
      Toronto, Ontario, Canada
  • 1976-1980
    • University of California, Santa Cruz
      Santa Cruz, California, United States
  • 1979
    • University of Padova
      Padua, Veneto, Italy
    • Washington State University
      • Department of Chemistry
      پولمن، واشینگتن, Washington, United States
    • Massachusetts Institute of Technology
      • Department of Chemistry
      Cambridge, Massachusetts, United States