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Wirtz L, Ghulam KY, Morgenstern B, Schäfer A. Constrained Geometry
ansa
‐Half‐Sandwich Complexes of Magnesium – Versatile
s
‐Block Catalysts. ChemCatChem 2022. [DOI: 10.1002/cctc.202201007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Lisa Wirtz
- Faculty of Natural Science and Technology Department of Chemistry Saarland University Campus Saarbrücken 66123 Saarbrücken Germany
| | - Kinza Yasmin Ghulam
- Faculty of Natural Science and Technology Department of Chemistry Saarland University Campus Saarbrücken 66123 Saarbrücken Germany
| | - Bernd Morgenstern
- Faculty of Natural Science and Technology Department of Chemistry Saarland University Campus Saarbrücken 66123 Saarbrücken Germany
| | - André Schäfer
- Faculty of Natural Science and Technology Department of Chemistry Saarland University Campus Saarbrücken 66123 Saarbrücken Germany
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2
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Reid AG, Hooe SL, Moreno JJ, Dickie DA, Machan CW. Homogeneous Electrocatalytic Reduction of CO 2 by a CrN 3O Complex: Electronic Coupling with a Redox-Active Terpyridine Fragment Favors Selectivity for CO. Inorg Chem 2022; 61:16963-16970. [PMID: 36260749 DOI: 10.1021/acs.inorgchem.2c02013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electrocatalyst design and optimization strategies continue to be an active area of research interest for the applied use of renewable energy resources. The electrocatalytic conversion of carbon dioxide (CO2) is an attractive approach in this context because of the added potential benefit of addressing its rising atmospheric concentrations. In previous experimental and computational studies, we have described the mechanism of the first molecular Cr complex capable of electrocatalytically reducing CO2 to carbon monoxide (CO) in the presence of an added proton donor, which contained a redox-active 2,2'-bipyridine (bpy) fragment, CrN2O2. The high selectivity for CO in the bpy-based system was dependent on a delocalized CrII(bpy•-) active state. Subsequently, we became interested in exploring how expanding the polypyridyl ligand core would impact the selectivity and activity during electrocatalytic CO2 reduction. Here, we report a new CrN3O catalyst, Cr(tpytbupho)Cl2 (1), where 2-(2,2':6',2″-terpyridin-6-yl)-4,6-di-tert-butylphenolate = [tpytbupho]-, which reduces CO2 to CO with almost quantitative selectivity via a different mechanism than our previously reported Cr(tbudhbpy)Cl(H2O) catalyst. Computational analyses indicate that, although the stoichiometry of both reactions is identical, changes in the observed rate law are the combined result of a decrease in the intrinsic ligand charge (L3X vs L2X2) and an increase in the ligand redox activity, which result in increased electronic coupling between the doubly reduced tpy fragment of the ligand and the CrII center. The strong electronic coupling enhances the rate of protonation and subsequent C-OH bond cleavage, resulting in CO2 binding becoming the rate-determining step, which is an uncommon mechanism during protic CO2 reduction.
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Affiliation(s)
- Amelia G Reid
- Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, Virginia22904-4319, United States
| | - Shelby L Hooe
- Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, Virginia22904-4319, United States
| | - Juan J Moreno
- Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, Virginia22904-4319, United States
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, Virginia22904-4319, United States
| | - Charles W Machan
- Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, Virginia22904-4319, United States
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3
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Baguli S, Mondal S, Mandal C, Goswami S, Mukherjee D. Cyclopentadienyl Complexes of the Alkaline Earths in Light of the Periodic Trends. Chem Asian J 2022; 17:e202100962. [PMID: 34825506 DOI: 10.1002/asia.202100962] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/02/2021] [Indexed: 11/09/2022]
Abstract
The electron-rich cyclopentadienyl and the analogous indenyl and fluorenyl ligands (collectively denoted here as Cp') have been impactful in stabilizing electron-deficient metal centers including the highly electropositive alkaline earths. Being in the s-block, the group 2 metals follow a major periodic variation in their atomic and ionic properties which is reflected in those Cp' compounds. This article presents an overview of this class of compounds for all the five metals from beryllium to barium (radium is excluded for its radioactivity), highlighting their systematic variation.
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Affiliation(s)
- Sudip Baguli
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Nadia, 741246, West Bengal, India
| | - Sumana Mondal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Nadia, 741246, West Bengal, India
| | - Chhotan Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Nadia, 741246, West Bengal, India
| | - Santu Goswami
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Nadia, 741246, West Bengal, India
| | - Debabrata Mukherjee
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Nadia, 741246, West Bengal, India
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Synthesis and structure of an asymmetrical sila[1]magnesocenophane. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2021. [DOI: 10.1515/znb-2021-0152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The synthesis and structure of an asymmetrical sila[1]magnesocenophane, featuring a cyclopentadienyl and a tetramethylcyclopentadienyl group, are reported. The compound was obtained as a bis(tetrahydrofuran) adduct and exhibits a slipped sandwich structure in the solid state.
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Wirtz L, Lambert J, Morgenstern B, Schäfer A. Cross-Dehydrocoupling of Amines and Silanes Catalyzed by Magnesocenophanes. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00245] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Lisa Wirtz
- Saarland University, Faculty of Natural Sciences and Technology, Department of Chemistry, Campus Saarbrücken, 66123 Saarbrücken, Federal Republic of Germany
| | - Jessica Lambert
- Saarland University, Faculty of Natural Sciences and Technology, Department of Chemistry, Campus Saarbrücken, 66123 Saarbrücken, Federal Republic of Germany
| | - Bernd Morgenstern
- Saarland University, Faculty of Natural Sciences and Technology, Department of Chemistry, Campus Saarbrücken, 66123 Saarbrücken, Federal Republic of Germany
| | - André Schäfer
- Saarland University, Faculty of Natural Sciences and Technology, Department of Chemistry, Campus Saarbrücken, 66123 Saarbrücken, Federal Republic of Germany
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Müller C, Warken J, Huch V, Morgenstern B, Bischoff I, Zimmer M, Schäfer A. Diphosphanylmetallocenes of Main-Group Elements. Chemistry 2021; 27:6500-6510. [PMID: 33411379 PMCID: PMC8252418 DOI: 10.1002/chem.202005198] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Indexed: 12/23/2022]
Abstract
Several 1,1'-diphosphanyl-substituted metallocenes of magnesium (magnesocenes) were synthesized, structurally characterized, and their reactivity and coordination chemistry were investigated. Transmetalation of these magnesocenes gives access to group 14 metallocenes (tetrelocenes), as well as to group 15 stibonocenes. These s- and p-block metallocenes represent a novel class of bis(phosphanyl) ligands, exhibiting Lewis-amphiphilic character. Their coordination chemistry towards different transition-metal and main-group fragments was investigated and different complexes are presented.
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Affiliation(s)
- Carsten Müller
- Faculty of Natural Sciences and TechnologyDepartment of ChemistrySaarland UniversityCampus Saarbrücken66123SaarbrückenGermany
| | - Joshua Warken
- Faculty of Natural Sciences and TechnologyDepartment of ChemistrySaarland UniversityCampus Saarbrücken66123SaarbrückenGermany
| | - Volker Huch
- Faculty of Natural Sciences and TechnologyDepartment of ChemistrySaarland UniversityCampus Saarbrücken66123SaarbrückenGermany
| | - Bernd Morgenstern
- Faculty of Natural Sciences and TechnologyDepartment of ChemistrySaarland UniversityCampus Saarbrücken66123SaarbrückenGermany
| | - Inga‐Alexandra Bischoff
- Faculty of Natural Sciences and TechnologyDepartment of ChemistrySaarland UniversityCampus Saarbrücken66123SaarbrückenGermany
| | - Michael Zimmer
- Faculty of Natural Sciences and TechnologyDepartment of ChemistrySaarland UniversityCampus Saarbrücken66123SaarbrückenGermany
| | - André Schäfer
- Faculty of Natural Sciences and TechnologyDepartment of ChemistrySaarland UniversityCampus Saarbrücken66123SaarbrückenGermany
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Moreno JJ, Hooe SL, Machan CW. DFT Study on the Electrocatalytic Reduction of CO 2 to CO by a Molecular Chromium Complex. Inorg Chem 2021; 60:3635-3650. [PMID: 33657314 DOI: 10.1021/acs.inorgchem.0c03136] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A variety of molecular transition metal-based electrocatalysts for the reduction of carbon dioxide (CO2) have been developed to explore the viability of utilization strategies for addressing its rising atmospheric concentrations and the corresponding effects of global warming. Concomitantly, this approach could also meet steadily increasing global energy demands for value-added carbon-based chemical feedstocks as nonrenewable petrochemical resources are consumed. Reports on the molecular electrocatalytic reduction of CO2 mediated by chromium (Cr) complexes are scarce relative to other earth-abundant transition metals. Recently, our group reported a Cr complex that can efficiently catalyze the reduction of CO2 to carbon monoxide (CO) at low overpotentials. Here, we present new mechanistic insight through a computational (density functional theory) study, exploring the origin of kinetic selectivity, relative energetic positioning of the intermediates, speciation with respect to solvent coordination and spin state, as well as the role of the redox-active bipyridine moiety. Importantly, these studies suggest that under certain reducing conditions, the formation of bicarbonate could become a competitive reaction pathway, informing new areas of interest for future experimental studies.
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Affiliation(s)
- Juan J Moreno
- Department of Chemistry, University of Virginia, McCormick Road PO Box 400319, Charlottesville, Virginia 22904-4319, United States
| | - Shelby L Hooe
- Department of Chemistry, University of Virginia, McCormick Road PO Box 400319, Charlottesville, Virginia 22904-4319, United States
| | - Charles W Machan
- Department of Chemistry, University of Virginia, McCormick Road PO Box 400319, Charlottesville, Virginia 22904-4319, United States
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Abstract
Metallocenes with interlinked cyclopentadienide ligands are commonly referred to as ansa-metallocenes or metallocenophanes. These can have drastically different properties than their unbridged parent compounds. While this concept is best known for transition metals such as iron, it can also be adopted for many main-group elements. This review aims to summarize recent advances in the field of metallocenophanes based on main-group elements of group 2, group 13, group 14 and group 15, focusing on synthesis, structure and properties of these compounds.
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Affiliation(s)
- Lisa Wirtz
- Faculty of Natural Science and TechnologyDepartment of ChemistrySaarland UniversityCampus Saarbrücken66123SaarbrückenGermany
| | - André Schäfer
- Faculty of Natural Science and TechnologyDepartment of ChemistrySaarland UniversityCampus Saarbrücken66123SaarbrückenGermany
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Wirtz L, Haider W, Huch V, Zimmer M, Schäfer A. Magnesocenophane-Catalyzed Amine Borane Dehydrocoupling. Chemistry 2020; 26:6176-6184. [PMID: 32052880 PMCID: PMC7318289 DOI: 10.1002/chem.202000106] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Indexed: 11/10/2022]
Abstract
The Lewis acidities of a series of [n]magnesocenophanes (1 a–d) have been investigated computationally and found to be a function of the tilt of the cyclopentadienyl moieties. Their catalytic abilities in amine borane dehydrogenation/dehydrocoupling reactions have been probed, and C[1]magnesocenophane (1 a) has been shown to effectively catalyze the dehydrogenation/dehydrocoupling of dimethylamine borane (2 a) and diisopropylamine borane (2 b) under ambient conditions. Furthermore, the mechanism of the reaction with 2 a has been investigated experimentally and computationally, and the results imply a ligand‐assisted mechanism involving stepwise proton and hydride transfer, with dimethylaminoborane as the key intermediate.
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Affiliation(s)
- Lisa Wirtz
- Faculty of Natural Science and Technology, Department of Chemistry, Saarland University, Campus Saarbrücken, 66123, Saarbrücken, Germany
| | - Wasim Haider
- Faculty of Natural Science and Technology, Department of Chemistry, Saarland University, Campus Saarbrücken, 66123, Saarbrücken, Germany
| | - Volker Huch
- Faculty of Natural Science and Technology, Department of Chemistry, Saarland University, Campus Saarbrücken, 66123, Saarbrücken, Germany
| | - Michael Zimmer
- Faculty of Natural Science and Technology, Department of Chemistry, Saarland University, Campus Saarbrücken, 66123, Saarbrücken, Germany
| | - André Schäfer
- Faculty of Natural Science and Technology, Department of Chemistry, Saarland University, Campus Saarbrücken, 66123, Saarbrücken, Germany
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Labrum NS, Chen C, Caulton KG. A
bis
‐Pyrazolate Pincer on Reduced Cr Deoxygenates CO
2
: Selective Capture of the Derived Oxide by Cr
II. Chemistry 2019; 25:7935-7940. [DOI: 10.1002/chem.201901134] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Nicholas S. Labrum
- Department of Chemistry and the Molecular Structure Center Indiana University Bloomington Indiana 47405 USA
| | - Chun‐Hsing Chen
- Department of Chemistry and the Molecular Structure Center Indiana University Bloomington Indiana 47405 USA
| | - Kenneth G. Caulton
- Department of Chemistry and the Molecular Structure Center Indiana University Bloomington Indiana 47405 USA
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12
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Estephane J, Groppo E, Vitillo JG, Damin A, Lamberti C, Bordiga S, Zecchina A. Chromocene in porous polystyrene: an example of organometallic chemistry in confined spaces. Phys Chem Chem Phys 2009; 11:2218-27. [DOI: 10.1039/b814109f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Mayer UFJ, Charmant JPH, Rae J, Manners I. Synthesis and Structures of Strained, Neutral [d7] and Cationic [d6] Hydrocarbon-Bridged [n]Cobaltocenophanes (n = 2, 3). Organometallics 2008. [DOI: 10.1021/om700941v] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ulrich F. J. Mayer
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K
| | | | - James Rae
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K
| | - Ian Manners
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K
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14
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Chadha P, Dutton JL, Sgro MJ, Ragogna PJ. Synthesis of Neutral Mixed Sandwich CH2-SiR2 Bridged [2]Cobaltoarenophanes from the Dilithiation of Cb*CoCp [Co(η4-C4Me4)(η5-C5H5)]. Organometallics 2007. [DOI: 10.1021/om700900e] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Preeti Chadha
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
| | - Jason L. Dutton
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
| | - Michael J. Sgro
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
| | - Paul J. Ragogna
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
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