1
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Shen Q, Sheng K, Gao ZY, Bilyachenko A, Huang XQ, Azam M, Tung CH, Sun D. Vanadium-Silsesquioxane Nanocages as Heterogeneous Catalysts for Synthesis of Quinazolinones. Inorg Chem 2024; 63:13022-13030. [PMID: 38946199 DOI: 10.1021/acs.inorgchem.4c01748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
The functionalization of polyoxovanadate clusters is promising but of great challenge due to the versatile coordination geometry and oxidation state of vanadium. Here, two unprecedented silsesquioxane ligand-protected "fully reduced" polyoxovanadate clusters were fabricated via a facial solvothermal methodology. The initial mixture of the two polyoxovanadate clusters with different colors and morphologies (green plate V14 and blue block V6) was successfully separated as pure phases by meticulously controlling the assembly conditions. Therein, the V14 cluster is the highest-nuclearity V-silsesquioxane cluster to date. Moreover, the transformation from a dimeric silsesquioxane ligand-protected V14 cluster to a cyclic hexameric silsesquioxane ligand-protected V6 cluster was also achieved, and the possible mechanism termed "ligand-condensation-involved dissociation reassembly" was proposed to explain this intricate conversion process. In addition, the robust V6 cluster was served as a heterogeneous catalyst for the synthesis of important heterocyclic compounds, quinazolinones, starting from 2-aminobenzamide and aldehydes. The V6 cluster exhibits high activity and selectivity to access pure quinazolinones under mild conditions, where the high selectivity was attributed to the confinement effect of the macrocyclic silsesquioxane ligand constraining the molecular freedom of the reaction species. The stability and recyclability as well as the tolerance of a wide scope of aldehyde substrates endow the V6 cluster with a superior performance and appreciable potential in catalytic applications.
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Affiliation(s)
- Qi Shen
- Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252000, People's Republic of China
| | - Kai Sheng
- School of Aeronautics, Shandong Jiaotong University, Ji'nan 250037, People's Republic of China
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Ji'nan 250100, People's Republic of China
| | - Zhi-Yong Gao
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, People's Republic of China
| | - Alexey Bilyachenko
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Street, Moscow 119334, Russian Federation
- Peoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, Moscow 117198, Russian Federation
| | - Xian-Qiang Huang
- Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252000, People's Republic of China
| | - Mohammad Azam
- Department of Chemistry, College of Science, King Saud University, PO BOX 2455 Riyadh 11451, Saudi Arabia
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Ji'nan 250100, People's Republic of China
| | - Di Sun
- Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252000, People's Republic of China
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Ji'nan 250100, People's Republic of China
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2
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Cooney SE, Schreiber E, Ferrigno BM, Matson EM. O 2 reduction via proton-coupled electron transfer by a V(III) aquo on a polyoxovanadate-alkoxide cluster. Chem Commun (Camb) 2024; 60:5610-5613. [PMID: 38713068 DOI: 10.1039/d4cc01331j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
We report the transfer of H-atoms from a reduced polyoxovanadate alkoxide [nOct4N][V6O6(OH2)(OMe)12] via concerted proton-electron transfer. Oxygen reduction is compared between bridging and terminal O-H bonds revealing similar mechanisms, providing new insight to design criteria for metal-oxide electrocatalysts that faciliate oxygen reduction by concerted-proton electron transfer.
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Affiliation(s)
- Shannon E Cooney
- Department of Chemistry, University of Rochester, Rochester NY 14627, USA.
| | - Eric Schreiber
- Department of Chemistry, University of Rochester, Rochester NY 14627, USA.
| | - Baela M Ferrigno
- Department of Chemistry, University of Rochester, Rochester NY 14627, USA.
| | - Ellen M Matson
- Department of Chemistry, University of Rochester, Rochester NY 14627, USA.
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3
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Proe KR, Towarnicky A, Fertig A, Lu Z, Mpourmpakis G, Matson EM. Impact of Surface Ligand Identity and Density on the Thermodynamics of H Atom Uptake at Polyoxovanadate-Alkoxide Surfaces. Inorg Chem 2024; 63:7206-7217. [PMID: 38592922 DOI: 10.1021/acs.inorgchem.3c04435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
An understanding of how molecular structure influences the thermodynamics of H atom transfer is critical to designing efficient catalysts for reductive chemistries. Herein, we report experimental and theoretical investigations summarizing structure-function relationships of polyoxovanadate-alkoxides that influence bond dissociation free energies of hydroxide ligands located at the surface of the cluster. We evaluate the thermochemical descriptors of O-H bond strength for a series of clusters, namely [V6O13-x(OH)x(TRIOLR)2]-2 (x = 2, 4, 6; R = NO2, Me) and [V6O11-x(OMe)2(OH)x(TRIOLNO2)2]-2, via computational analysis and open circuit potential measurements. Our findings reveal that modifications to the TRIOL ligand (e.g., changing from the previously reported electron withdrawing nitro-backed ligand to the electron-donating methyl variant) have limited influence on the strength of surface O-H bonds as a result of near complete thermodynamic compensation in these systems (i.e., correlated changes in redox potential and cluster basicity). In contrast, changes in surface density of alkoxide ligands via direct alkoxylation of the polyoxovanadate-alkoxide surface result in measurable increases in bond dissociation free energies of surface O-H bonds for the mixed-valent derivatives. Our findings indicate that the extent of (de)localization of electron density across the cluster core has an impact on the bond dissociation free energies of surface O-H bonds across all oxidation states of the assembly.
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Affiliation(s)
- Kathryn R Proe
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Andreas Towarnicky
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Alex Fertig
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Zhou Lu
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Ellen M Matson
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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4
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Lu Z, Cooney SE, McKone JR, Matson EM. Selective Hydrogenation of Azobenzene to Hydrazobenzene via Proton-Coupled Electron Transfer from a Polyoxotungstate Cluster. JACS AU 2024; 4:1310-1314. [PMID: 38665657 PMCID: PMC11041919 DOI: 10.1021/jacsau.4c00127] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Revised: 03/05/2024] [Accepted: 03/14/2024] [Indexed: 04/28/2024]
Abstract
In this report, we describe proton-coupled electron transfer (PCET) reactivity at the surface of the Keggin-type polyoxotungstate cluster [nBu4N]3[PWVI12O40] (PW12) in acetonitrile. Bond dissociation free energies (BDFEs) of the O-H groups generated upon reduction of PW12 in the presence of acid are determined through the construction of a potential-pKa diagram. The surface O-H bonds are found to be weak (BDFE(O-H)avg < 48 kcal mol-1), comparable to the BDFE of H2. This is consistent with the observed formation of H2 upon addition of a suitably strong organic acid, H2NPh2+ (pKa MeCN = 5.98), to the reduced form of the cluster. The one-electron reduced form of PW12 is isolated and used in conjunction with acid to realize the stoichiometric semihydrogenation of azobenzene via PCET from the surface of the reduced cluster.
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Affiliation(s)
- Zhou Lu
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Shannon E. Cooney
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - James R. McKone
- Departments
of Chemical and Petroleum Engineering and Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Ellen M. Matson
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
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5
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Cooney S, Walls MRA, Schreiber E, Brennessel WW, Matson EM. Heterometal Dopant Changes the Mechanism of Proton-Coupled Electron Transfer at the Polyoxovanadate-Alkoxide Surface. J Am Chem Soc 2024; 146:2364-2369. [PMID: 38241170 PMCID: PMC10835708 DOI: 10.1021/jacs.3c14054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 01/21/2024]
Abstract
The transfer of two H-atom equivalents to the titanium-doped polyoxovanadate-alkoxide, [TiV5O6(OCH3)13], results in the formation of a V(III)-OH2 site at the surface of the assembly. Incorporation of the group (IV) metal ion results in a weakening of the O-H bonds of [TiV5O5(OH2)(OCH3)13] in comparison to its homometallic congener, [V6O6(OH2)(OCH3)12], resembling more closely the thermodynamics reported for the one-electron reduced derivative, [V6O6(OH2)(OCH3)12]1-. An analysis of early time points of the reaction of [TiV5O6(OCH3)13] and 5,10-dihydrophenazine reveals the formation of an oxidized substrate, suggesting that proton-coupled electron transfer proceeds via initial electron transfer from substrate to cluster prior to proton transfer. These results demonstrate the profound influence of heterometal dopants on the mechanism of PCET with respect to the surface of the assembly.
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Affiliation(s)
- Shannon
E. Cooney
- Department of Chemistry, University
of Rochester, Rochester, New York 14627, United States
| | - M. Rebecca A. Walls
- Department of Chemistry, University
of Rochester, Rochester, New York 14627, United States
| | - Eric Schreiber
- Department of Chemistry, University
of Rochester, Rochester, New York 14627, United States
| | - William W. Brennessel
- Department of Chemistry, University
of Rochester, Rochester, New York 14627, United States
| | - Ellen M. Matson
- Department of Chemistry, University
of Rochester, Rochester, New York 14627, United States
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6
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Cogan NB, McClelland KP, Peter CYM, Carmenate Rodríguez C, Fertig AA, Amin M, Brennessel WW, Krauss TD, Matson EM. Efficient Hole Transfer from CdSe Quantum Dots Enabled by Oxygen-Deficient Polyoxovanadate-Alkoxide Clusters. NANO LETTERS 2023; 23:10221-10227. [PMID: 37935022 PMCID: PMC10683070 DOI: 10.1021/acs.nanolett.3c02749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 10/25/2023] [Accepted: 10/26/2023] [Indexed: 11/09/2023]
Abstract
A limitation of the implementation of cadmium chalcogenide quantum dots (QDs) in charge transfer systems is the efficient removal of photogenerated holes. Rapid hole transfer has typically required the ex situ functionalization of hole acceptors with groups that can coordinate to the surface of the QD. In addition to being synthetically limiting, this strategy also necessitates a competitive binding equilibrium between the hole acceptor and native, solubilizing ligands on the nanocrystal. Here we show that the incorporation of oxygen vacancies into polyoxovanadate-alkoxide clusters improves hole transfer kinetics by promoting surface interactions between the metal oxide assembly and the QD. Investigating the reactivity of oxygen-deficient clusters with phosphonate-capped QDs reveals reversible complexation of the POV-alkoxide with a phosphonate ligand at the nanocrystal surface. These findings reveal a new method of facilitating QD-hole acceptor association that bypasses the restrictions of exchange interactions.
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Affiliation(s)
- Nicole
M. B. Cogan
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Kevin P. McClelland
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Chari Y. M. Peter
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | | | - Alex A. Fertig
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Mitesh Amin
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - William W. Brennessel
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Todd D. Krauss
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
- Institute
of Optics, University of Rochester, Rochester, New York 14627, United States
| | - Ellen M. Matson
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
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7
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Peter CYM, Schreiber E, Proe KR, Matson EM. Surface ligand length influences kinetics of H-atom uptake in polyoxovanadate-alkoxide clusters. Dalton Trans 2023; 52:15775-15785. [PMID: 37850536 DOI: 10.1039/d3dt02074f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
The uptake of hydrogen atoms (H-atoms) at reducible metal oxide nanocrystal surfaces has implications in catalysis and energy storage. However, it is often difficult to gain insight into the physicochemical factors that dictate the thermodynamics and kinetics of H-atom transfer to the surface of these assemblies. Recently, our research group has demonstrated the formation of oxygen-atom (O-atom) defects in polyoxovanadate-alkoxide (POV-alkoxide) clusters via conversion of surface oxido moieties to aquo ligands, which can be accomplished via addition of two H-atom equivalents. Here, we present the dependence of O-atom defect formation via H-atom transfer at the surface of vanadium oxide clusters on the length of surface alkoxide ligands. Analysis of H-atom transfer reactions to low-valent POV-alkoxide clusters [V6O7(OR)12]1- (R = Me, Et, nPr, nBu) reveals that the length of primary alkoxide surface ligands does not significantly influence the thermodynamics of these processes. However, surface ligand length has a significant impact on the kinetics of these PCET reactions. Indeed, the methoxide-bridged cluster, [V6O7(OMe)12]1- reacts ∼20 times faster than the other derivatives evaluated. Interestingly, as the aliphatic linkages are increased in size from -C2H5 to -C4H9, reaction rates remain consistent, suggesting restricted access to available ligand conformers as a result of the incompatibility of the aliphatic ligands and acetonitrile may buffer further changes to the rate of reaction.
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Affiliation(s)
- Chari Y M Peter
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA.
| | - Eric Schreiber
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA.
| | - Kathryn R Proe
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA.
| | - Ellen M Matson
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA.
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8
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Nelson YA, Irshad A, Kim S, Waddington MA, Salamat CZ, Gembicky M, Rheingold AL, Carta V, Tolbert S, Narayan SR, Spokoyny AM. Vertex Differentiation Strategy for Tuning the Physical Properties of closo-Dodecaborate Weakly Coordinating Anions. Inorg Chem 2023; 62:15084-15093. [PMID: 37667823 PMCID: PMC11152248 DOI: 10.1021/acs.inorgchem.3c01992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
We report the synthesis and characterization of various compounds containing the 1,7,9-hydroxylated closo-dodecahydrododecaborate (B12H9(OH)32-) cluster motif. Specifically, we show how the parent compound can be synthesized on the multigram scale and further perhalogenated, leading to a new class of vertex-differentiated weakly coordinating anions. We show that a postmodification of the hydroxyl groups by alkylation affords further opportunities for tailoring these anions' stability, steric bulk, and solubility properties. The resulting dodecaborate-based salts were subjected to a full thermal and electrochemical stability evaluation, showing that many of these anions maintain thermal stability up to 500 °C and feature no redox activity below ∼1 V vs Fc/Fc+. Mixed hydroxylated/halogenated clusters show enhanced solubility compared to their purely halogenated analogs and retain weakly coordinating properties in the solid state, as demonstrated by ionic conductivity measurements of their Li+ salts.
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Affiliation(s)
- Yessica A. Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Ahamed Irshad
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Sangmin Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Mary A. Waddington
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Charlene Z. Salamat
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Milan Gembicky
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - Arnold L. Rheingold
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - Veronica Carta
- Department of Chemistry and Biochemistry, University of California, Riverside, Riverside, California 92521, USA
| | - Sarah Tolbert
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
- Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Sri R. Narayan
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Alexander M. Spokoyny
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
- California NanoSystems Institute (CNSI), University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, CA 90095, USA
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9
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Repp S, Remmers M, Rein ASJ, Sorsche D, Gao D, Anjass M, Mondeshki M, Carrella LM, Rentschler E, Streb C. Coupled reaction equilibria enable the light-driven formation of metal-functionalized molecular vanadium oxides. Nat Commun 2023; 14:5563. [PMID: 37689696 PMCID: PMC10492840 DOI: 10.1038/s41467-023-41257-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 08/29/2023] [Indexed: 09/11/2023] Open
Abstract
The introduction of metal sites into molecular metal oxides, so-called polyoxometalates, is key for tuning their structure and reactivity. The complex mechanisms which govern metal-functionalization of polyoxometalates are still poorly understood. Here, we report a coupled set of light-dependent and light-independent reaction equilibria controlling the mono- and di-metal-functionalization of a prototype molecular vanadium oxide cluster. Comprehensive mechanistic analyses show that coordination of a Mg2+ ion to the species {(NMe2H2)2[VV12O32Cl]}3- results in formation of the mono-functionalized {(NMe2H2)[(MgCl)VV12O32Cl]}3- with simultaneous release of a NMe2H2+ placeholder cation. Irradiation of this species with visible light results in one-electron reduction of the vanadate, exchange of the second NMe2H2+ with Mg2+, and formation/crystallization of the di-metal-functionalized [(MgCl)2VIVVV11O32Cl]4-. Mechanistic studies show how stimuli such as light or competing cations affect the coupled equilibria. Transfer of this synthetic concept to other metal cations is also demonstrated, highlighting the versatility of the approach.
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Affiliation(s)
- Stefan Repp
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Moritz Remmers
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | | | - Dieter Sorsche
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Dandan Gao
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Montaha Anjass
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Department of Chemistry, University of Sharjah, Sharjah-27272, Sharjah, United Arab Emirates
| | - Mihail Mondeshki
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Luca M Carrella
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Eva Rentschler
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Carsten Streb
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
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10
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Falaise C, Mpacko Priso G, Leclerc N, Haouas M, Cadot E. Making Heterometallic Metal-Metal Bonds in Keggin-Type Polyoxometalates by a Six-Electron Reduction Process. Inorg Chem 2023; 62:2494-2502. [PMID: 36716738 DOI: 10.1021/acs.inorgchem.2c03769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Polyoxometalates (POMs) represent a promising class of molecular electron reservoirs. However, their multielectron reduction gives rise to intricate physical-chemical phenomena that must be fully understood for their future use in energy-storage devices. Herein, we show that bulk electrolysis of the archetypal Keggin-type POM [Si(WVI2MoVIO10)(WVI3O10)3]4- in aqueous solution leads to the six-electron-reduced derivative [Si(WIV2MoIVO7(H2O)3)(WVI3O10)3]4- (notated SiW11Mo-VI') in which the mixed-metal triad acts as a storage unit for six electrons and six protons. X-ray diffraction analysis and multinuclear NMR (183W and 95Mo) studies reveal that this electron-rich species represents the first example of POMs containing heterometallic metal-metal bonds between addenda centers. This electron-rich POM can be further reduced through multielectronic events, while its full oxidation restores the structure of the oxidized parent ion. Remarkably, the formation of SiW11Mo-VI' results from a fast clustering process compared to that observed for the entirely W-based analogue, revealing that the formation of metal-metal bonds in the mixed-metal Mo/W POM is facilitated because the reaction rate is not limited by a slow disproportionation step. Last, we evaluate the supramolecular properties of SiW11Mo-VI' using a method based on the cloud-point measurement of a nonionic surfactant. This investigation demonstrates that the clustering process has dramatic consequences on the solution behavior of the POM, canceling its superchaotropic character due to a local structuring effect of the hydration shell. These fundamental results pave the way for applications using the massive electron-storage properties of mixed-metal POMs.
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Affiliation(s)
- Clément Falaise
- Institut Lavoisier de Versailles, CNRS, UVSQ, Université Paris-Saclay, 45 avenue des Etats-Unis, 78035Versailles, France
| | - Gabrielle Mpacko Priso
- Institut Lavoisier de Versailles, CNRS, UVSQ, Université Paris-Saclay, 45 avenue des Etats-Unis, 78035Versailles, France
| | - Nathalie Leclerc
- Institut Lavoisier de Versailles, CNRS, UVSQ, Université Paris-Saclay, 45 avenue des Etats-Unis, 78035Versailles, France
| | - Mohamed Haouas
- Institut Lavoisier de Versailles, CNRS, UVSQ, Université Paris-Saclay, 45 avenue des Etats-Unis, 78035Versailles, France
| | - Emmanuel Cadot
- Institut Lavoisier de Versailles, CNRS, UVSQ, Université Paris-Saclay, 45 avenue des Etats-Unis, 78035Versailles, France
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11
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Schreiber E, Brennessel WW, Matson EM. Regioselectivity of concerted proton-electron transfer at the surface of a polyoxovanadate cluster. Chem Sci 2023; 14:1386-1396. [PMID: 36794190 PMCID: PMC9906639 DOI: 10.1039/d2sc05928b] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 12/19/2022] [Indexed: 01/19/2023] Open
Abstract
Proton-coupled electron transfer (PCET) is an important process in the activation and reactivity of metal oxide surfaces. In this work, we study the electronic structure of a reduced polyoxovanadate-alkoxide cluster bearing a single bridging oxide moiety. The structural and electronic implications of the incorporation of bridging oxide sites are revealed, most notably resulting in the quenching of cluster-wide electron delocalization in the most reduced state of the molecule. We correlate this attribute to a change in regioselectivity of PCET to the cluster surface (e.g. reactivity at terminal vs. bridging oxide groups). Reactivity localized at the bridging oxide site enables reversible storage of a single H-atom equivalent, changing the stoichiometry of PCET from a 2e-/2H+ process. Kinetic investigations indicate that the change in site of reactivity translates to an accelerated rate of e-/H+ transfer to the cluster surface. Our work summarizes the role which electronic occupancy and ligand density play in the uptake of e-/H+ pairs at metal oxide surfaces, providing design criteria for functional materials for energy storage and conversion processes.
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Affiliation(s)
- Eric Schreiber
- Department of Chemistry, University of Rochester Rochester NY 14611 USA
| | | | - Ellen M Matson
- Department of Chemistry, University of Rochester Rochester NY 14611 USA
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12
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Cooney SE, Fertig AA, Buisch MR, Brennessel WW, Matson EM. Coordination-induced bond weakening of water at the surface of an oxygen-deficient polyoxovanadate cluster. Chem Sci 2022; 13:12726-12737. [PMID: 36519047 PMCID: PMC9645371 DOI: 10.1039/d2sc04843d] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/10/2022] [Indexed: 10/19/2023] Open
Abstract
Hydrogen-atom (H-atom) transfer at the surface of heterogeneous metal oxides has received significant attention owing to its relevance in energy conversion and storage processes. Here, we present the synthesis and characterization of an organofunctionalized polyoxovanadate cluster, (calix)V6O5(OH2)(OMe)8 (calix = 4-tert-butylcalix[4]arene). Through a series of equilibrium studies, we establish the BDFE(O-H)avg of the aquo ligand as 62.4 ± 0.2 kcal mol-1, indicating substantial bond weaking of water upon coordination to the cluster surface. Subsequent kinetic isotope effect studies and Eyring analysis indicate the mechanism by which the hydrogenation of organic substrates occurs proceeds through a concerted proton-electron transfer from the aquo ligand. Atomistic resolution of surface reactivity presents a novel route of hydrogenation reactivity from metal oxide surfaces through H-atom transfer from surface-bound water molecules.
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Affiliation(s)
- Shannon E Cooney
- Department of Chemistry, University of Rochester Rochester NY 14627 USA
| | - Alex A Fertig
- Department of Chemistry, University of Rochester Rochester NY 14627 USA
| | | | | | - Ellen M Matson
- Department of Chemistry, University of Rochester Rochester NY 14627 USA
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Mitchell BS, Chirila A, Kephart JA, Boggiano AC, Krajewski SM, Rogers D, Kaminsky W, Velian A. Metal-Support Interactions in Molecular Single-Site Cluster Catalysts. J Am Chem Soc 2022; 144:18459-18469. [PMID: 36170652 DOI: 10.1021/jacs.2c07033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study provides atomistic insights into the interface between a single-site catalyst and a transition metal chalcogenide support and reveals that peak catalytic activity occurs when edge/support redox cooperativity is maximized. A molecular platform MCo6Se8(PEt3)4(L)2 (1-M, M = Cr, Mn, Fe, Co, Cu, and Zn) was designed in which the active site (M)/support (Co6Se8) interactions are interrogated by systematically probing the electronic and structural changes that occur as the identity of the metal varies. All 3d transition metal 1-M clusters display remarkable catalytic activity for coupling tosyl azide and tert-butyl isocyanide, with Mn and Co derivatives showing the fastest turnover in the series. Structural, electronic, and magnetic characterization of the clusters was performed using single crystal X-ray diffraction, 1H and 31P nuclear magnetic resonance spectroscopy, electronic absorption spectroscopy, cyclic voltammetry, and computational methods. Distinct metal/support redox regimes can be accessed in 1-M based on the energy of the edge metal's frontier orbitals with respect to those of the cluster support. As the degree of electronic interaction between the edge and the support increases, a cooperative regime is reached wherein the support can deliver electrons to the catalytic site, increasing the reactivity of key metal-nitrenoid intermediates.
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Affiliation(s)
- Benjamin S Mitchell
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Andrei Chirila
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Jonathan A Kephart
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Andrew C Boggiano
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Sebastian M Krajewski
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Dylan Rogers
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Werner Kaminsky
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Alexandra Velian
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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Fertig AA, Matson EM. Connecting Thermodynamics and Kinetics of Proton Coupled Electron Transfer at Polyoxovanadate Surfaces Using the Marcus Cross Relation. Inorg Chem 2022; 62:1958-1967. [PMID: 36049052 PMCID: PMC9906739 DOI: 10.1021/acs.inorgchem.2c02541] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Here, we evaluate the efficacy of multiple methods for elucidating the average bond dissociation free energy (BDFE) of two surface hydroxide moieties in a reduced polyoxovanadate cluster, [V6O11(OH)2(TRIOLNO2)2]-2. Through cyclic voltammetry, individual thermochemical parameters describing proton coupled electron transfer (PCET) are obtained, without the need for synthetic isolation of intermediates. Further, we demonstrate that a method involving a series of open circuit potential measurements with varying ratios of reduced to oxidized clusters is most attractive for the direct measurement of BDFE(O-H) for polyoxovanadate clusters as this approach also determines the stoichiometry of PCET. We subsequently connect the driving force of PCET to the rate constant for the transfer of hydrogen atoms to a series of organic substrates through the Marcus cross relation. We show that this method is applicable for the prediction of reaction rates for multielectron/multiproton transfer reactions, extending the findings from previous work focused on single electron/proton reactions.
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Valerio LR, Hakey B, Brennessel WW, Matson E. Quantitative U=O bond activation in uranyl complexes via silyl radical transfer. Chem Commun (Camb) 2022; 58:11244-11247. [DOI: 10.1039/d2cc04424b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reductive silylation of the uranyl dication with 1,4-bis(trimethylsilyl)dihydropyrazine, or “Mashima’s Reagent”, is detailed. The substrate simultaneously delivers silylium ions and electrons to multiple uranyl complexes (e.g. pyridine dipyrrolide uranyl complex...
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