1
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Samudrala KK, Conley MP. Effects of surface acidity on the structure of organometallics supported on oxide surfaces. Chem Commun (Camb) 2023; 59:4115-4127. [PMID: 36912586 DOI: 10.1039/d3cc00047h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Well-defined organometallics supported on high surface area oxides are promising heterogeneous catalysts. An important design factor in these materials is how the metal interacts with the functionalities on an oxide support, commonly anionic X-type ligands derived from the reaction of an organometallic M-R with an -OH site on the oxide. The metal can either form a covalent M-O bond or form an electrostatic M+⋯-O ion-pair, which impacts how well-defined organometallics will interact with substrates in catalytic reactions. A less common reaction pathway involves the reaction of a Lewis site on the oxide with the organometallic, resulting in abstraction to form an ion-pair, which is relevant to industrial olefin polymerization catalysts. This Feature Article views the spectrum of reactivity between an organometallic and an oxide through the prism of Brønsted and/or Lewis acidity of surface sites and draws analogies to the molecular frame where Lewis and Brønsted acids are known to form reactive ion-pairs. Applications of the well-defined sites developed in this article are also discussed.
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Affiliation(s)
| | - Matthew P Conley
- Department of Chemistry, University of California, Riverside, California 92521, USA.
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2
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Handford RC, Nguyen TT, Teat SJ, Britt RD, Tilley TD. Direct Transformation of SiH 4 to a Molecular L(H) 2Co═Si═Co(H) 2L Silicide Complex. J Am Chem Soc 2023; 145:3031-3039. [PMID: 36696099 DOI: 10.1021/jacs.2c11569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The synthesis of bimetallic molecular silicide complexes is reported, based on the use of multiple Si-H bond activations in SiH4 at the metal centers of 14-electron LCoI fragments (L = Tp″, HB(3,5-diisopropylpyrazolyl)3-; [BP2tBuPz], PhB(CH2PtBu2)2(pyrazolyl)). Upon exposure of (Tp″Co)2(μ-N2) (1) to SiH4, a mixture of (Tp″Co)2(μ-H) (2) and (Tp″Co)2(μ-H)2 (3) was formed and no evidence for Si-H oxidative addition products was observed. In contrast, [BP2tBuPz]-supported Co complexes led to Si-H oxidative additions with the generation of silylene and silicide complexes as products. Notably, the reaction of ([BP2tBuPz]Co)2(μ-N2) (5) with SiH4 gave the dicobalt silicide complex [BP2tBuPz](H)2Co═Si═Co(H)2[BP2tBuPz] (8) in high yield, representing the first direct route to a symmetrical bimetallic silicide. The effect of the [BP2tBuPz] ligand on Co-Si bonding in 7 and 8 was explored by analysis of solid-state molecular structures and density functional theory (DFT) investigations. Upon exposure to CO or DMAP (DMAP = 4-dimethylaminopyridine), 8 converted to the corresponding [BP2tBuPz]Co(L)x adducts (L = CO, x = 2; L = DMAP, x = 1) with concomitant loss of SiH4, despite the lack of significant Si-H interactions in the starting complex. On heating to 60 °C, 8 underwent reaction with MeCl to produce small quantities of MexSiH4-x (x = 1-3), demonstrating functionalization of the μ-silicon atom in a molecular silicide to form organosilanes.
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Affiliation(s)
- Rex C Handford
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Trisha T Nguyen
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Simon J Teat
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - R David Britt
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - T Don Tilley
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
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3
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Bekyarova E, Conley MP. The coordination chemistry of oxide and nanocarbon materials. Dalton Trans 2022; 51:8557-8570. [PMID: 35586978 DOI: 10.1039/d2dt00459c] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Understanding how a ligand affects the steric and electronic properties of a metal is the cornerstone of the inorganic chemistry enterprise. What happens when the ligand is an extended surface? This question is central to the design and implementation of state-of-the-art functional materials containing transition metals. This perspective will describe how these two very different sets of extended surfaces can form well-defined coordination complexes with metals. In the Green formalism, functionalities on oxide surfaces react with inorganics to form species that contain X-type or LX-type interactions between the metal and the oxide. Carbon surfaces are neutral L-type ligands; this perspective focuses on carbons that donate six electrons to a metal. The nature of this interaction depends on the curvature, and thereby orbital overlap, between the metal and the extended π-system from the nanocarbon.
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Affiliation(s)
- Elena Bekyarova
- Department of Chemistry, University of California, Riverside, California 92521, USA.
| | - Matthew P Conley
- Department of Chemistry, University of California, Riverside, California 92521, USA.
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4
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Huynh W, Taylor JW, Harman WH, Conley MP. Solid-state 11B NMR studies of coinage metal complexes containing a phosphine substituted diboraanthracene ligand. Dalton Trans 2021; 50:14855-14863. [PMID: 34604875 DOI: 10.1039/d1dt02981a] [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
Transition metal interactions with Lewis acids (M → Z linkages) are fundamentally interesting and practically important. The most common Z-type ligands contain boron, which contains an NMR active 11B nucleus. We measured solid-state 11B{1H} NMR spectra of copper, silver, and gold complexes containing a phosphine substituted 9,10-diboraanthracene ligand (B2P2) that contain planar boron centers and weak M → BR3 linkages ([(B2P2)M][BArF4] (M = Cu (1), Ag (2), Au (3)) characterized by large quadrupolar coupling (CQ) values (4.4-4.7 MHz) and large span (Ω) values (93-139 ppm). However, the solid-state 11B{1H} NMR spectrum of K[Au(B2P2)]- (4), which contains tetrahedral borons, is narrow and characterized by small CQ and Ω values. DFT analysis of 1-4 shows that CQ and Ω are expected to be large for planar boron environments and small for tetrahedral boron, and that the presence of a M → BR3 linkage relates to the reduction in CQ and 11B NMR shielding properties. Thus solid-state 11B NMR spectroscopy contains valuable information about M → BR3 linkages in complexes containing the B2P2 ligand.
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Affiliation(s)
- Winn Huynh
- Department of Chemistry, University of California, Riverside, California 92521, USA.
| | - Jordan W Taylor
- Department of Chemistry, University of California, Riverside, California 92521, USA.
| | - W Hill Harman
- Department of Chemistry, University of California, Riverside, California 92521, USA.
| | - Matthew P Conley
- Department of Chemistry, University of California, Riverside, California 92521, USA.
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5
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Kumar N, Laye C, Robert F, Landais Y. Quinoline‐Based Silylium Ions: Synthesis, Structure and Lewis Acidity. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Nivesh Kumar
- Univ. Bordeaux, CNRS Institut des Sciences Moléculaires (ISM), UMR-5255 33400 Talence France
| | - Claire Laye
- Univ. Bordeaux, CNRS Institut des Sciences Moléculaires (ISM), UMR-5255 33400 Talence France
| | - Frédéric Robert
- Univ. Bordeaux, CNRS Institut des Sciences Moléculaires (ISM), UMR-5255 33400 Talence France
| | - Yannick Landais
- Univ. Bordeaux, CNRS Institut des Sciences Moléculaires (ISM), UMR-5255 33400 Talence France
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6
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Réant BLL, Berryman VEJ, Basford AR, Nodaraki LE, Wooles AJ, Tuna F, Kaltsoyannis N, Mills DP, Liddle ST. 29Si NMR Spectroscopy as a Probe of s- and f-Block Metal(II)-Silanide Bond Covalency. J Am Chem Soc 2021; 143:9813-9824. [PMID: 34169713 DOI: 10.1021/jacs.1c03236] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the use of 29Si NMR spectroscopy and DFT calculations combined to benchmark the covalency in the chemical bonding of s- and f-block metal-silicon bonds. The complexes [M(SitBu3)2(THF)2(THF)x] (1-M: M = Mg, Ca, Yb, x = 0; M = Sm, Eu, x = 1) and [M(SitBu2Me)2(THF)2(THF)x] (2-M: M = Mg, x = 0; M = Ca, Sm, Eu, Yb, x = 1) have been synthesized and characterized. DFT calculations and 29Si NMR spectroscopic analyses of 1-M and 2-M (M = Mg, Ca, Yb, No, the last in silico due to experimental unavailability) together with known {Si(SiMe3)3}--, {Si(SiMe2H)3}--, and {SiPh3}--substituted analogues provide 20 representative examples spanning five silanide ligands and four divalent metals, revealing that the metal-bound 29Si NMR isotropic chemical shifts, δSi, span a wide (∼225 ppm) range when the metal is kept constant, and direct, linear correlations are found between δSi and computed delocalization indices and quantum chemical topology interatomic exchange-correlation energies that are measures of bond covalency. The calculations reveal dominant s- and d-orbital character in the bonding of these silanide complexes, with no significant f-orbital contributions. The δSi is determined, relatively, by paramagnetic shielding for a given metal when the silanide is varied but by the spin-orbit shielding term when the metal is varied for a given ligand. The calculations suggest a covalency ordering of No(II) > Yb(II) > Ca(II) ≈ Mg(II), challenging the traditional view of late actinide chemical bonding being equivalent to that of the late lanthanides.
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Affiliation(s)
- Benjamin L L Réant
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Victoria E J Berryman
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Annabel R Basford
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Lydia E Nodaraki
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Ashley J Wooles
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Floriana Tuna
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Nikolas Kaltsoyannis
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - David P Mills
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Stephen T Liddle
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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7
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Bläsing K, Labbow R, Schulz A, Villinger A. Silylated Sulfuric Acid: Preparation of a Tris(trimethylsilyl)oxosulfonium [(Me 3 Si-O) 3 SO] + Salt. Angew Chem Int Ed Engl 2021; 60:13798-13802. [PMID: 33913571 PMCID: PMC8251596 DOI: 10.1002/anie.202104733] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Indexed: 12/16/2022]
Abstract
The chemistry of silylated sulfuric acid, O2 S(OSiMe3 )2 (T2 SO4 , T=Me3 Si; also known as bis(trimethylsilyl) sulfate), has been studied in detail with the aim of synthesizing the formal autosilylation products of silylated sulfuric acid, [T3 SO4 ]+ and [TSO4 ]- , in analogy to the known protonated species, [H3 SO4 ]+ and [HSO4 ]- . The synthesis of the [TSO4 ]- ion only succeeds when a base, such as OPMe3 that forms a weakly coordinating cation upon silylation, is reacted with T2 SO4 , resulting in the formation of [Me3 POT]+ [TSO4 ]- . [T3 SO4 ]+ salts could be isolated starting from T2 SO4 in the reaction with [T-H-T]+ [B(C6 F5 )4 ]- or T+ [CHB11 Br6 H5 ]- when a weakly coordinating anion is used as counterion. All silylated compounds could be crystallized and structurally characterized.
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Affiliation(s)
- Kevin Bläsing
- Institut für ChemieUniversität RostockAlbert-Einstein-Strasse 3a18059RostockGermany
| | - Rene Labbow
- Institut für ChemieUniversität RostockAlbert-Einstein-Strasse 3a18059RostockGermany
| | - Axel Schulz
- Institut für ChemieUniversität RostockAlbert-Einstein-Strasse 3a18059RostockGermany
- Leibniz-Institut für Katalyse e.V.Albert-Einstein-Strasse 29a18059RostockGermany
| | - Alexander Villinger
- Institut für ChemieUniversität RostockAlbert-Einstein-Strasse 3a18059RostockGermany
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8
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Bläsing K, Labbow R, Schulz A, Villinger A. Silylierte Schwefelsäure: Herstellung eines Tris(trimethylsilyl)oxosulfonium[(Me
3
Si‐O)
3
SO]
+
‐Salzes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202104733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Kevin Bläsing
- Institut für Chemie Universität Rostock Albert-Einstein-Straße 3a 18059 Rostock Deutschland
| | - Rene Labbow
- Institut für Chemie Universität Rostock Albert-Einstein-Straße 3a 18059 Rostock Deutschland
| | - Axel Schulz
- Institut für Chemie Universität Rostock Albert-Einstein-Straße 3a 18059 Rostock Deutschland
- Leibniz-Institut für Katalyse e.V. Albert-Einstein-Straße 29a 18059 Rostock Deutschland
| | - Alexander Villinger
- Institut für Chemie Universität Rostock Albert-Einstein-Straße 3a 18059 Rostock Deutschland
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9
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Yi X, Peng YK, Chen W, Liu Z, Zheng A. Surface Fingerprinting of Faceted Metal Oxides and Porous Zeolite Catalysts by Probe-Assisted Solid-State NMR Approaches. Acc Chem Res 2021; 54:2421-2433. [PMID: 33856775 DOI: 10.1021/acs.accounts.1c00069] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Acid catalysis in heterogeneous systems such as metal oxides and porous zeolites has been widely involved in various catalytic processes for chemical and petrochemical industries. In acid-catalyzed reactions, the performance (e.g., activity and selectivity) is closely associated with the acidic features of the catalysts, viz., type (Lewis vs Brønsted acidity), distribution (external vs internal surface), strength (strong vs weak), concentration (amount), and spatial interactions of acidic sites. The characterization of local structure and acidic properties of these active sites has important implications for understanding the reaction mechanism and the practical catalytic applications of acidic catalysts. Among diverse acidity characterization approaches, the solid-state nuclear magnetic resonance (SSNMR) technique with suitable probe molecules has been recognized as a reliable and versatile tool. Such a probe-assisted SSNMR approach could provide qualitative (type, distribution, and spatial interactions) and quantitative (strength and concentration) information on each acidic site. This Account aims to integrate our recent important findings in determining the structures and acidic characteristics of some typical metal oxide and zeolite catalysts by using the probe-assisted SSNMR technique, as well as clarifying the continuously evolving process of each discrete acidic site under hydrothermal or chemical treatments even at the molecular level with multiscale theoretical simulations.More specifically, we will describe herein the development and applications of the probe-assisted SSNMR methods, such as trimethylphosphine (TMP) and acetonitrile-d3 (CD3CN) in conjunction with advanced two-dimensional (2D) homo- and heteronuclear correlation spectroscopy, for characterizing the structures and properties of acidic sites in varied solid catalysts. Moreover, relevant information regarding the surface fingerprinting of various facets on crystalline metal oxide nanoparticles and active centers inside porous zeolites, the mapping of relevant spatial interactions, and the verification of structure-activity correlation were investigated as well. Relevant discussions are mainly based on the recent NMR experiments of our collaborating research groups, including (i) determining the acidic characterization with probe-assisted SSNMR approaches, (ii) mapping various active centers (or crystalline facets), and (iii) revealing their influence on catalytic performance of solid acid catalyst systems. It is anticipated that this information may provide more in-depth insights toward our fundamental understanding of solid acid catalysis.
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Affiliation(s)
- Xianfeng Yi
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Yung-Kang Peng
- Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
| | - Wei Chen
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Zhiqiang Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Anmin Zheng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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10
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Gordon CP, Lätsch L, Copéret C. Nuclear Magnetic Resonance: A Spectroscopic Probe to Understand the Electronic Structure and Reactivity of Molecules and Materials. J Phys Chem Lett 2021; 12:2072-2085. [PMID: 33617260 DOI: 10.1021/acs.jpclett.0c03520] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This Perspective focuses on the ability of chemical shift to identify and characterize the electronic structure and associated reactivity of molecules and materials. After a general introduction on NMR parameters, we will show selected examples where the chemical shift of various NMR active nuclei has been used to investigate and understand electronic properties, with a particular focus on organometallic compounds and inorganic materials with relevance to catalysis. We will demonstrate how the NMR parameter of probe molecules and ligands can be used to elucidate the nature of active sites and how they can help to understand and predict their reactivity. Lastly, we will give an overview over recent advances in deciphering metal NMR parameters. Overall, we show how chemical shift is a reactivity descriptor that can be analyzed and understood on a molecular level.
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Affiliation(s)
- Christopher P Gordon
- ETH Zurich, Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zurich, Switzerland
| | - Lukas Lätsch
- ETH Zurich, Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zurich, Switzerland
| | - Christophe Copéret
- ETH Zurich, Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zurich, Switzerland
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11
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Witzke RJ, Chapovetsky A, Conley MP, Kaphan DM, Delferro M. Nontraditional Catalyst Supports in Surface Organometallic Chemistry. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03350] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryan J. Witzke
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Alon Chapovetsky
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Matthew P. Conley
- Department of Chemistry, University of California, Riverside, Riverside, California 92521, United States
| | - David M. Kaphan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Massimiliano Delferro
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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