Yurii V Geletii

Yurii V Geletii
Emory University | EU · Department of Chemistry

PhD

About

161
Publications
346,745
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Introduction
I'm just retired from Emory University and serve as a consultant in the Department of Chemistry. I would be willing to consult any company or scholar for a reasonable fee.
Additional affiliations
June 1999 - present
Emory University
Position
  • Senior Researcher
November 1993 - August 1997
Laboratoire de Chimie de Coordination.
Position
  • Research Director
December 1992 - August 1996
French National Centre for Scientific Research
Position
  • Directer de rechersh

Publications

Publications (161)
Chapter
Full-text available
From multiple perspectives, d-block-metal-substituted polyoxometalates (POMs) represent synthetically tunable homogeneous analogs of many transition metal oxides. Both classes of materials have a range of catalytic activities derived from the presence of redox active metals in all-oxygen ligand environments. These carbon-free environments provide f...
Preprint
Full-text available
Mixed 3d-metal oxides are some of the most promising water oxidation catalysts (WOCs), but it is very difficult to know the active site structures and thus structure-catalytic activity correlations at the molecular level in such insoluble materials. This study reports a molecular water oxidation catalyst, [Co 2 Ni 2 (PW 9 O 34 ) 2 ] ¹⁰⁻ (Co 2 Ni 2...
Article
Full-text available
Bis(2-chloroethyl) sulfide or sulfur mustard (HD) is one of the highest-tonnage chemical warfare agents and one that is highly persistent in the environment. For decontamination, selective oxidation of HD to the substantially less toxic sulfoxide is crucial. We report here a solvent-free, solid, robust catalyst comprising hydrophobic salts of tribr...
Article
Full-text available
Tafel analysis of electrocatalysts is essential in their characterization. This paper analyzes the application of Tafel-like analysis to the four-electron nonelectrochemical oxidation of water by the stoichiometric homogeneous 1-electron oxidant [Ru(bpy)3]3+ to dioxygen catalyzed by homogeneous catalysts, [Ru4O4(OH)2(H2O)4(γ-SiW10O36)2]10− (Ru4POM)...
Article
A series of heterogeneous catalysts based on phosphomolybdic salts with different Lewis metals in counter or substituent places LnPMo12O40 (L = Al3+, Fe3+, Cr3+, Ti4+, Zr4+ and Zn2+, abbreviated as LPMo12) and HxPMo11LO39 (L = Zn2+, Cr3+, Fe3+, Al3+, Ti4+, for Ti4+, the amount of O is 40, abbreviated as HPMo11L) have been prepared using simple dehy...
Article
Glycerol is a co-product in the manufacture of biodiesel from vegetable oil and animal fat. A significant increase in biodiesel production results in adramatic overproduction of glycerol. The oxidation of glycerol to lactic acid (LA) by O2 is considered to be a promising technology to increase the value of glycerol. Studies on the fundamental react...
Article
Our group reported that the polyoxometalate Na10[Co4V2W18O68] • 26 H2O (Co4V2) is an active water oxidation catalyst and provided characterization of this system (J. Am. Chem. Soc. 2014, 136 (26), 9268). Two recent publications called into question the stability of Co4V2, one noting the miss-assignment of a 51V NMR peak (Inorg. Chem. 2016, 55 (11),...
Article
Full-text available
Polyoxometalate (POM)-based materials of current interest are summarized, and specific types of POM-containing systems are described in which material facilitates multiple complex interactions or catalytic processes. We specifically highlight POM-containing multi-hydrogen-bonding polymers that form gels upon exposure to select organic liquids and s...
Article
Polyoxometalates (POMs) and in particularly Keggin heteropolytungstates are much studied and commercially important catalysts for dioxygen-based oxidation processes. The rate-limiting step in many POM-catalyzed O2-based oxidations is reoxidation of the reduced POM by O2. We report here that this reoxidation process, as represented by the one-electr...
Article
Full-text available
The polyoxometalate [Co4(L)2(PW9O34)2]¹⁰⁻, where L is typically H2O, (1) is a much-studied homogeneous water oxidation catalyst that facilitates the conversion of water to dioxygen through a mechanism that remains poorly understood due to difficulty measuring electrochemical and acid–base properties in aqueous media. Studies in a non-aqueous, polar...
Chapter
Catalysts in solar fuel research have greatly increased in the last few years. Significantly, the development of molecular, selective, and faster catalysts for both water oxidation or water reduction based on polyoxometalates has lead to advances in the understanding of water splitting systems. Recent studies have combined molecular catalysts with...
Research
Full-text available
HOMOGENEOUS WATER OXIDATION CATALYZED BY CO-BASED POLYOXOMETALATES
Article
Highly efficient electrocatalytic oxidation of ethanol and methanol has been achieved using a ruthenium containing polyoxometalate molecular catalyst, [{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]10- ([1(γ-SiW10O36)2]10-). Voltammetric studies with dissolved and surface confined forms of [1(γ-SiW10O36)2]10- suggest that the oxidized forms of 1 can act as activ...
Article
The reaction of reduced polyoxometalates (POMs) with dioxygen is centrally important in POM catalysis. We report that this process, as represented by the one-electron-reduced Keggin complexes POMred (α-AlW12O406-, α-SiW12O405-, and α-PW12O404-), is efficiently catalyzed by copper complexes. The Cu-catalyzed pathway is dominant in the presence of as...
Article
A new structural polyoxometalate motif, [{Ni4 (OH)3 AsO4 }4 (B-α-PW9 O34 )4 ](28-) , which contains the highest nuclearity structurally characterized multi-nickel-containing polyanion to date, has been synthesized and characterized by single-crystal X-ray diffraction, temperature-dependent magnetism and several other techniques. The unique central...
Article
Visible light driven water oxidation has been demonstrated at near-neutral pH using photoanodes based on nanoporous films of TiO2, polyoxometalate (POM) water oxidation catalyst [{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]10- (1), and both known photosensitizer [Ru(bpy)2(H4dpbpy)]2+ (P2) and the novel crown ether functionalized dye [Ru(5-crownphen)2(H2dpbpy)]...
Article
A tetra-nickel-containing polyoxotungstate, Na6K4[Ni4(H2O)2(PW9O34)2] •32H2O (Na6K4-Ni4P2), has been synthesized in high yield and systematically characterized. The X-ray crystal structure confirms that a tetra-nickel cluster core [Ni4O14] is sandwiched by two tri-vacant, heptadentate [PW9O34]9- POM ligands. When coupled with (4,4'-di-tert-butyl-2,...
Article
The H2O insoluble complex of title ([RuIIbipy]5[RuIII4POM]) is prepared by reduction of Rb8K2 [{RuIV4O4(OH)2 (H2O)4} (γ-SiW10O36)2] with NaBH4 followed by precipitation with [Ru(bipy)3]Cl2.
Patent
Full-text available
Homogeneous water oxidation catalysts (WOCs) for the oxidation of water to produce hydrogen ions and oxygen, and methods of making and using thereof are described herein. In a preferred embodiment, the WOC is a polyoxometalate WOC which is hydrolytically stable, oxidatively stable, and thermally stable. The WOC oxidized waters in the presence of an...
Article
The water insoluble complex Rb4[Ru(II)(bpy)3]5[{Ru(III)4O4(OH)2(H2O)4}(γ-SiW10O36)2], ([Ru(II)bpy]5[Ru(III)4POM]), was synthesized from Rb8K2[{Ru(IV)4O4(OH)2(H2O)4}(γ-SiW10O36)2] and used for electrocatalytic water oxidation under both thin- and thick-film electrode conditions. Results demonstrate that the [Ru(II)bpy]5[Ru(III)4POM] modified electro...
Article
An all-inorganic, oxidatively and thermally stable, homogeneous WOC based on redox-active (vanadate(V)-centered) POM ligands, Na10[Co4(H2O)2(VW9O34)2]∙35H2O (Na101-V2, sodium salt of the polyanion 1-V2), was synthesized, thoroughly characterized and shown to catalyze water oxidation in dark and visible-light-driven conditions. This synthetic cataly...
Chapter
Catalytic water oxidation is indispensable to solar fuel production. We have developed a family of soluble water oxidation catalysts (WOCs) based on polyoxometalates (POMs) that address many issues of concern or interest to the solar fuels research community: POM WOCs are soluble so their properties can be extensively probed experimentally and comp...
Article
As the field of water oxidation catalysis grows, so does the sophistication of the associated experimental apparatuses. However, problems persist in studying some of the most basic aspects of catalytic water oxidation including acquisition of satisfactory early-reaction-time kinetics and rapid quantification of O2 concentration. We seek to remedy t...
Article
The viable production of solar fuels requires a visible-light-absorbing unit, a H2O (or CO2) reduction catalyst (WRC), and a water oxidation catalyst (WOC) that work in tandem to split water or reduce CO2 with H2O rapidly, selectively, and for long periods of time. Most catalysts and photosensitizers developed to date for these triadic systems are...
Article
Full-text available
Hydrogen sulfate salts of [Ru(1)2]2+ where 1 = 4′-(4-pyridyl)-2,2′:6′,2′′-terpyridine and four N-alkylated derivatives [Ru(L)2]4+ were used as photosensitizers (λmax 510 nm) for water oxidation in light driven reactions with peroxydisulfate as a sacrificial electron acceptor and Na10[Co4(H2O)2(α-PW9O34)2] (Co4POM) as the catalyst in sodium borate b...
Article
Na17 [(Co(OH2)Co2VW9O34)2 (VW6O26)]·31H2O (I) is synthesized from Na2WO4, Co(NO3)2, and V2O5 in acetate buffer solution (pH 4.8, 80 °C, 2 h, 24% yield).
Article
A polyoxometalate-supported trirhenium carbonyl cluster, mimicking metal oxide supported interfacial dyadic structures, has been synthesized and characterized. Multiple techniques, including computational and transient absorption spectroscopy, have been applied to characterize the charge-transfer dynamics occurring at the interfaces of this "double...
Article
In an effort to address the need to develop hydrolytically more stable, molecular water reduction catalysts (WRCs) amenable to in-depth investigation, we report here one prototype: a tetra-manganese-containing V-centered polyoxotungstate, Na-10[Mn-4(H2O)(2)(VW9O34)(2)] (1). The electronic structure of 1 was elucidated using the OFT approach. Comple...
Article
Voltammetric studies of the Ru-containing polyoxometalate water oxidation molecular catalyst [{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2](10-) ([1(γ-SiW10O36)2](10-) where 1 represents the {Ru4O4(OH)2(H2O)4} core and 1(0) stands for its initial form with all ruthenium centers in the oxidation state IV) have been carried out in aqueous media over a wide range...
Article
Distinguishing between homogeneous and heterogeneous catalysis is not straightforward. In the case of the water oxidation catalyst (WOC) [Co4(H2O)2(PW9O34)2]10- (Co4POM), initial reports of an efficient, molecular catalyst have been challenged by studies suggesting that formation of cobalt oxide (CoOx) or other byproducts are responsible for the ca...
Article
The electrochemistry of the Ru-containing polyoxometalate (POM) water oxidation molecular catalyst, Rb8K2[{Ru4O4(OH)2(H2O)4}(gamma-SiW10O36)2]10- (Rb8K2-1), has been studied by cyclic and rotating disk electrode voltammetric methods in aqueous media under acidic and neutral pH conditions using bare glassy carbon (GC) and graphene modified GC electr...
Article
Compounds (IV), (V), and (VI) are characterized by single crystal XRD, cyclic voltammetry, IR, and UV/VIS spectroscopy.
Article
The compound (4-H2pya)3[Al(OH)6Mo6O18]·5H2O (1) transforms into two 2D hybrid species (4-Hpya)[(4-Hpya)Ln(H2O)5]2[Al(OH)6Mo6O18]2·13H2O {Ln = Ce (2), La (3); 4-Hpya = 3-(4-pyridyl)acrylic acid} in the mother liquor through crystal dissolution and recrystallization; this represents a rare example of in situ recrystallization involving polyoxometalat...
Article
The hexanuclear cobalt-containing tungstovanadate complex, Na17[(Co(OH2)Co2VW9O34)2(VW6O26)]·31H2O (1) has been synthesized through reaction of cobalt nitrate, sodium tungstate, and V2O5 in acetate buffer solution. The title compound has been characterized by X-ray crystallography, elemental analysis, FTIR, UV/Vis, and 51V NMR spectroscopy and by c...
Article
Di- and tricobalt silicotungstate complexes, K(5)Na(4)H(4)[{Na(3)(μ-OH(2))(2)Co(2)(μ-OH)(4)} (Si(2)W(18)O(66))]·37H(2)O (1) and K(6)Na(3)[Na(H(2)O){Co(H(2)O)(3)}(2){Co(H(2)O)(2)}(Si(2)W(18)O(66))]·22H(2)O (2), have been synthesized through reaction of cobalt chloride and [A-α-SiW(9)O(34)](10-) in acidic buffer solution. They have been characterized...
Article
The electrochemistry of the water oxidation catalyst, Rb(8)K(2)[{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(γ-SiW(10)O(36))(2)] (Rb(8)K(2)-1(0)) has been studied in the presence and absence of potassium cations in both hydrochloric and sulfuric acid solutions by transient direct current (dc) cyclic voltammetry, a steady state dc method in the rotating disk config...
Article
A new pentanickel silicotungstate complex, K(10)H(2)[Ni(5)(OH)(6)(OH(2))(3)(Si(2)W(18)O(66))]·34H(2)O (KH-), has been synthesized and characterized by X-ray crystallography and several other methods. Dynamic light scattering, kinetics and other experiments confirm that in the presence of [Ru(bpy)(3)](2+) (the photosensitizer for light-driven water...
Article
In the last five years and currently, research on solar fuels has been intense and no sub-area in this field has been more active than the development of water oxidation catalysts (WOCs). In this timeframe, a new class of molecular water oxidation catalysts based on polyoxometalates have been reported that combine the advantages of homogeneous and...
Article
A dodecazinc silicotungstate K(20)Na(2)[Zn(6)(OH)(7)(H(2)O)(Si(2)W(18)O(66))](2)·34H(2)O (1) has been synthesized and characterized by X-ray crystallography, elemental analysis, infrared, UV-vis spectroscopy, cyclic voltammetry, acid-base titration, and DFT calculations. The twelve zinc atoms between the two [Si(2)W(18)O(66)](16-) frameworks make t...
Article
Terminal oxo complexes of the late transition metals Pt, Pd, and Au have been reported by us in Science and Journal of the American Chemical Society. Despite thoroughness in characterizing these complexes (multiple independent structural methods and up to 17 analytical methods in one case), we have continued to study these structures. Initial work...
Article
This review is focused on the spectroscopic studies of the charge transfer dynamics in polyoxometalate (POM)-catalyzed artificial photodriven water oxidation systems. We first describe the general challenges in solar fuel production, showing that water oxidation catalysts (WOCs) are of central importance. After the introduction of a new class of hi...
Article
We report a study on catalytic water oxidation by cobalt in oxygen ligand environments because such systems are as promising as any in the water oxidation component of solar fuel production. We have re-examined the catalytic activity of Co(II) in aqueous solution using either [Ru(bpy)3]3+ as a stoichiometric oxidant or in visible-light-driven react...
Article
Catalysts for multi-electron-transfer events are quite complicated just as the reactions they facilitate. Two classes of such catalysts, those for the air-based oxidation of organic compounds and those for the oxidation of water, are addressed in this chapter. Brief backgrounds in both these areas are provided followed by the ensemble of current ch...
Article
Full-text available
A new polyoxometalate of earth adundant elements [{Co(4)(μ-OH)(H(2)O)(3)}(Si(2)W(19)O(70))](11-) has been synthesized, characterized and shown to be a water oxidation catalyst. The initial catalytic complex is unstable and slowly undergoes hydrolysis. The hydrolysis products have been isolated and characterized, and their catalytic water oxidation...
Article
Full-text available
The mechanism of reaction of the di-Ru-substituted polyoxometalate, {γ-[(H2O)RuIII(μ-OH)2RuIII(H2O)][X n+W10O36]}(8−n)−, I_X, with O2, i.e. I_X + O2 → {γ-[(·O)RuIV(μ-OH)2RuIV(O·)][X n+W10O36]}(8−n)− + 2H2O, (1), was studied at the B3LYP density functional and self-consistent reaction field IEF-PCM (in aqueous solution) levels of theory. The effect...
Article
Many studies have noted that mixtures of nitrogen oxides (or oxyanions; NOx = NO3–, NO2–, NO–, etc.) and halide (particularly bromine) with or without a transition metal salt (most frequently, copper and iron complexes) are fast and highly selective catalysts for aerobic sulfoxidation and decontamination of many oxidizable toxic compounds. However,...
Article
New multi-cobalt-containing polyoxometalates (POMs) are soluble, fast and tunable water oxidation catalysts (WOCs). We report additional studies of [Co4(H2O)2(PW9O34)2]10- (1), a very fast, soluble and oxidative stable WOC: new kinetics data further indicate that Co2+ is not kinetically important in water oxidations catalyzed by 1. Second, we repor...
Article
Efficient solar-driven catalytic water oxidation is one of the main challenges in solar-to-fuel conversion. In this proceeding, we investigate three approaches for constructing electron acceptor -sensitizer - catalysts systems for photocatalytic water oxidation and our current understanding of the relevant fundamental processes involved. We demonst...
Article
Water oxidation catalysts (WOCs) are of core importance in several green energy production technologies, including water splitting and water reduction of CO2 driven by electrochemical potential and/or photons (radiant energy). General challenges in solar fuel generating structures, WOC design concepts, and some success-limiting considerations in WO...
Article
The abundant-metal-based polyoxometalate complex [Co(4)(H(2)O)(2)(PW(9)O(34))(2)](10-) is a hydrolytically and oxidatively stable, homogeneous, and efficient molecular catalyst for the visible-light-driven catalytic oxidation of water. Using a sacrificial electron acceptor and photosensitizer, it exhibits a high (30%) photon-to-O(2) yield and a lar...
Article
To probe photoinduced water oxidation catalyzed by the Mn₄O₄L₆ cubane clusters, we have computationally studied the mechanism and controlling factors of the O₂ formation from the [Mn₄O₄L₆] catalyst, 6. It was demonstrated that dissociation of an L = H₂PO₂⁻ ligand from 6 facilitates the direct O-O bond formation that proceeds with a 28.3 (33.4) kcal...
Article
Concerted proton-electron transfer (CPET) is documented for the homogeneous reduction of O2 to HO2· in water by the one-electron-reduced heteropolytungstate anion, α-PW12O 404- (11e). At 0.01-0.3 M H+, O 2 reduction occurs via outer-sphere electron transfer followed by proton transfer (ETPT, with rate constant kET). Between 0.30 and 1.9 M H+, rates...
Article
The mechanism and electron transfer dynamics of the reaction [Ru(II)(mptpy)(2)](4+) + hnu + [S(2)O(8)](2-) --> [Ru(III)(mptpy)(2)](5+) + SO(4)(2-) + SO(4)(-*) were studied using various computational (density functional and exciton interaction theories) and experimental (transient absorption, static and time-resolved fluorescence spectroscopy, and...
Article
The tetraruthenium-substituted polyoxometalate Cs(9)[(gamma-PW(10)O(36))(2)Ru(4)O(5)(OH)(H(2)O)(4)] was synthesized and structurally, spectroscopically and electrochemically characterized; it was shown to be a catalyst for visible-light-induced water oxidation.
Article
Full-text available
Traditional homogeneous water oxidation catalysts are plagued by instability under the reaction conditions. We report that the complex [Co4(H2O)2(PW9O34)2]10–, comprising a Co4O4 core stabilized by oxidatively resistant polytungstate ligands, is a hydrolytically and oxidatively stable homogeneous water oxidation catalyst that self-assembles in wa...
Chapter
After decades of speculation and attempted synthesis, terminal metal-oxo compounds of the late transition metal elements have been prepared. Terminal Pt-, Pd-, and Au-oxo complexes have been made using polytungstate ligands that share geometrical and electronic structural features and chemical properties (acid-base and others) in common with the me...
Article
Geometry and electronic structure of five species [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](10-) (1), [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](9-) (2), [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](8-) (3), [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](7-) (4), and [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)...
Article
We examine the mechanism of electron transfer between [Ru(bpy)(3)](2+) and [S(2)O(8)](2-) in aqueous solutions using time-dependent density functional and transition charge density model levels of theory. The calculations support the existence of a short-lived, optically bright S1 state that decays to lower-lying triplet states T1 and T2. The T1 st...
Article
Several key properties of the water oxidation catalyst Rb(8)K(2)[{Ru(IV)(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)] and its mechanism of water oxidation are given. The one-electron oxidized analogue [{Ru(V)Ru(IV)(3)O(6)(OH(2))(4)}(gamma-SiW(10)O(36))(2)](11-) has been prepared and thoroughly characterized. The voltammetric rest potentials, X-...