1
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Wang L, Wang L, Li M, Chong Q, Meng F. Cobalt-Catalyzed Diastereo- and Enantioselective Reductive Allyl Additions to Aldehydes with Allylic Alcohol Derivatives via Allyl Radical Intermediates. J Am Chem Soc 2021; 143:12755-12765. [PMID: 34352174 DOI: 10.1021/jacs.1c05690] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Catalytic generation of ambiphilic π-allyl-metal complexes and their utility in enantioselective transformations constitutes a powerful approach for introduction of allyl groups to a molecule. Herein an unprecedented cobalt-catalyzed highly site-, diastereo-, and enantioselective protocol for stereoselective formation of nucleophilic allyl-Co(II) complexes followed by addition to aldehydes is presented. The reaction features diastereo- and enantioconvergent conversion of easily accessible allylic alcohol derivatives to diversified enantioenriched homoallylic alcohols with a remarkably broad scope of allyl groups that can be introduced. Mechanistic studies indicated that allyl radical intermediates were involved in this process. These new discoveries establish a new strategy for development of enantioselective transformations through capture of radicals by chiral Co complexes, pushing forward the frontier of Co complexes for enantioselective catalysis.
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Affiliation(s)
- Lei Wang
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Lifan Wang
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Mingxia Li
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Qinglei Chong
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Fanke Meng
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
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2
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Omoruyi U, Page SJ, Apps SL, White AJ, Long NJ, Miller PW. Synthesis and characterisation of a range of Fe, Co, Ru and Rh triphos complexes and investigations into the catalytic hydrogenation of levulinic acid. J Organomet Chem 2021. [DOI: 10.1016/j.jorganchem.2020.121650] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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3
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Kim YB, Kim D, Dighe SU, Chang S, Park JW. Cobalt-Hydride-Catalyzed Hydrosilylation of 3-Alkynes Accompanying π-Bond Migration. ACS Catal 2021. [DOI: 10.1021/acscatal.0c05424] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yeong Bum Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalization, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Dongwook Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalization, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Shashikant U. Dighe
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalization, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Sukbok Chang
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalization, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Jung-Woo Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalization, Institute for Basic Science (IBS), Daejeon 34141, Korea
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4
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Gray M, Hines MT, Parsutkar MM, Wahlstrom AJ, Brunelli NA, RajanBabu TV. Mechanism of Cobalt-Catalyzed Heterodimerization of Acrylates and 1,3-Dienes. A Potential Role of Cationic Cobalt(I) Intermediates. ACS Catal 2020; 10:4337-4348. [PMID: 32457820 DOI: 10.1021/acscatal.9b05455] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Coupling reactions of feedstock alkenes are promising, but few of these reactions are practiced industrially. Even though recent advances in the synthetic methodology have led to excellent regio- and enantioselectivies in the dimerization reactions between 1,3-dienes and acrylates, the efficiency as measured by the turnover numbers (TON) in the catalyst has remained modest. Through a combination of reaction progress kinetic analysis (RPKA) of a prototypical dimerization reaction, characterization of isolated low-valent cobalt catalyst precursors involved, several important details of the mechanism of this reaction have emerged. (i) The prototypical reaction has an induction period that requires at least two hours of stir time to generate the competent catalyst. (ii) Reduction of a Co(II) complex to a Co(I) complex, and subsequent generation of a cationic [Co(I)]+ species are responsible for this delay. (iii) Through RPKA using in situ IR spectroscopy, same excess experiments reveal inhibition by the product towards the end of the reaction and no catalyst deactivation is observed as long as diene is present in the medium. The low TON observed is most likely the result of the inherent instability of the putative cationic Co(I)-species that catalyzes the reaction. (iv) Different excess experiments suggest that the reaction is first order in the diene and zero order in the acrylate. (v) Catalyst loading experiments show that the catalyst is first order. The orders in the various regents were further confirmed by Variable Time Normalization Analysis (VTNA). (vi) A mechanism based on oxidative dimerization [via Co(I)/Co(III)-cycle] is proposed. Based on the results of this study, it is possible to increase the TON by a factor of 10 by conducting the reaction at an increased concentration of the starting materials, especially, the diene, which seems to stabilize the catalytic species.
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Affiliation(s)
- Montgomery Gray
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210, United States
| | - Michael T. Hines
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff, Columbus, Ohio 43210, United States
| | - Mahesh M. Parsutkar
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210, United States
| | - A. J. Wahlstrom
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff, Columbus, Ohio 43210, United States
| | - Nicholas A. Brunelli
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff, Columbus, Ohio 43210, United States
| | - T. V. RajanBabu
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210, United States
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5
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Spin Crossover in 3D Metal Centers Binding Halide-Containing Ligands: Magnetism, Structure and Computational Studies. SUSTAINABILITY 2020. [DOI: 10.3390/su12062512] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The capability of a given substance to change its spin state by the action of a stimulus, such as a change in temperature, is by itself a very challenging property. Its interest is increased by the potential applications and the need to find sustainable functional materials. 3D transition metal complexes, mainly with octahedral geometry, display this property when coordinated to particular sets of ligands. The prediction of this behavior has been attempted by many authors. It is, however, made very difficult because spin crossover (SCO), as it is called, occurs most often in the solid state, where besides complexes, counter ions, and solvents are also present in many cases. Intermolecular interactions definitely play a major role in SCO. In this review, we decided to analyze SCO in mono- and binuclear transition metal complexes containing halogens as ligands or as substituents of the ligands. The aim was to try and find trends in the properties which might be correlated to halogen substitution patterns. Besides a revision of the properties, we analyzed structures and other information. We also tried to build a simple model to run Density Functional Theory (DFT) calculations and calculate several parameters hoping to find correlations between calculated indices and SCO data. Although there are many experimental studies and single-crystal X-ray diffraction structures, there are only few examples with the F, Cl, Br and series. When their intermolecular interactions were not very different, T1/2 (temperature with 50% high spin and 50% low spin states) usually increased with the calculated ligand field parameter (Δoct) within a given family. A way to predict SCO remains elusive.
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6
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Peters M, Baabe D, Maekawa M, Bockfeld D, Zaretzke MK, Tamm M, Walter MD. Pogo-Stick Iron and Cobalt Complexes: Synthesis, Structures, and Magnetic Properties. Inorg Chem 2019; 58:16475-16486. [PMID: 31769666 DOI: 10.1021/acs.inorgchem.9b02411] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis, structures, and magnetic properties of monomeric half-sandwich iron and cobalt imidazolin-2-iminato complexes have been comprehensively investigated. Salt metathesis reactions of [Cp'M(μ-I)]2 (1-M, M = Fe, Co; Cp' = η5-1,2,4-tri-tert-butylcyclopentadienyl) with [ImDippNLi]2 (ImDippN = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-iminato) furnishes the terminal half-sandwich compounds [Cp'M(NImDipp)] (2-M, M = Fe, Co), which can be regarded as models for elusive half-sandwich iron and cobalt imido complexes. X-ray diffraction analysis confirmed the structure motif of a one-legged piano stool. Complex 2-Co can also be prepared by an acid-base reaction between [Cp'Co{N(SiMe3)2}] (3-Co) and ImDippNH. The electronic and magnetic properties of 2-M and 3-Co were probed by 57Fe Mössbauer spectroscopy (M = Fe), X-band EPR spectroscopy (M = Co), and solid-state magnetic susceptibility measurements. In particular, the central metal atom adopts a high-spin (S = 2) state in 2-Fe, while the cobalt complex 2-Co represents a rare example of a Co(II) species with a coordination number different from six displaying a low-spin to high-spin spin-crossover (SCO) behavior. The experimental observations are complemented by DFT calculations.
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Affiliation(s)
- Marius Peters
- Institut für Anorganische und Analytische Chemie , Technische Universität Braunschweig , Hagenring 30 , 38106 Braunschweig , Germany
| | - Dirk Baabe
- Institut für Anorganische und Analytische Chemie , Technische Universität Braunschweig , Hagenring 30 , 38106 Braunschweig , Germany
| | - Miyuki Maekawa
- Institut für Anorganische und Analytische Chemie , Technische Universität Braunschweig , Hagenring 30 , 38106 Braunschweig , Germany
| | - Dirk Bockfeld
- Institut für Anorganische und Analytische Chemie , Technische Universität Braunschweig , Hagenring 30 , 38106 Braunschweig , Germany
| | - Marc-Kevin Zaretzke
- Institut für Anorganische und Analytische Chemie , Technische Universität Braunschweig , Hagenring 30 , 38106 Braunschweig , Germany
| | - Matthias Tamm
- Institut für Anorganische und Analytische Chemie , Technische Universität Braunschweig , Hagenring 30 , 38106 Braunschweig , Germany
| | - Marc D Walter
- Institut für Anorganische und Analytische Chemie , Technische Universität Braunschweig , Hagenring 30 , 38106 Braunschweig , Germany
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7
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Petuker A, Reback ML, Apfel U. Carbon/Silicon Exchange at the Apex of Diphos‐ and Triphos‐Derived Ligands – More Than Just a Substitute? Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700388] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Anette Petuker
- Ruhr University Bochum Inorganic Chemistry I ‐ Bioinorganic Chemistry Universitätsstraße 150 44801 Bochum Germany
| | - Matthew L. Reback
- Ruhr University Bochum Inorganic Chemistry I ‐ Bioinorganic Chemistry Universitätsstraße 150 44801 Bochum Germany
| | - Ulf‐Peter Apfel
- Ruhr University Bochum Inorganic Chemistry I ‐ Bioinorganic Chemistry Universitätsstraße 150 44801 Bochum Germany
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8
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Petuker A, Gerschel P, Piontek S, Ritterskamp N, Wittkamp F, Iffland L, Miller R, van Gastel M, Apfel UP. Spectroscopic and reactivity differences in metal complexes derived from sulfur containing Triphos homologs. Dalton Trans 2017; 46:13251-13262. [DOI: 10.1039/c7dt01459g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spectroscopic, computational, and reactivity studies shed light on the different coordination behavior of sulfur containing Triphos derived complexes.
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Affiliation(s)
- A. Petuker
- Anorganische Chemie I
- Ruhr-Universität Bochum
- D-44801 Bochum
- Germany
| | - P. Gerschel
- Anorganische Chemie I
- Ruhr-Universität Bochum
- D-44801 Bochum
- Germany
| | - S. Piontek
- Anorganische Chemie I
- Ruhr-Universität Bochum
- D-44801 Bochum
- Germany
| | - N. Ritterskamp
- Anorganische Chemie I
- Ruhr-Universität Bochum
- D-44801 Bochum
- Germany
| | - F. Wittkamp
- Anorganische Chemie I
- Ruhr-Universität Bochum
- D-44801 Bochum
- Germany
| | - L. Iffland
- Anorganische Chemie I
- Ruhr-Universität Bochum
- D-44801 Bochum
- Germany
| | - R. Miller
- Anorganische Chemie I
- Ruhr-Universität Bochum
- D-44801 Bochum
- Germany
| | - M. van Gastel
- Max-Planck-Institut für Chemische Energiekonversion
- 45470 Mülheim
- Germany
| | - U.-P. Apfel
- Anorganische Chemie I
- Ruhr-Universität Bochum
- D-44801 Bochum
- Germany
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9
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Petuker A, Merz K, Merten C, Apfel UP. Controlled Flexible Coordination in Tripodal Iron(II) Phosphane Complexes: Effects on Reactivity. Inorg Chem 2016; 55:1183-91. [DOI: 10.1021/acs.inorgchem.5b02361] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anette Petuker
- Inorganic Chemistry I and ‡Physical Organic Chemistry, Ruhr University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Klaus Merz
- Inorganic Chemistry I and ‡Physical Organic Chemistry, Ruhr University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Christian Merten
- Inorganic Chemistry I and ‡Physical Organic Chemistry, Ruhr University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Ulf-Peter Apfel
- Inorganic Chemistry I and ‡Physical Organic Chemistry, Ruhr University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
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10
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Phanopoulos A, Long NJ, Miller PW. Triphosphine Ligands: Coordination Chemistry and Recent Catalytic Applications. THE CHEMICAL BOND III 2016. [DOI: 10.1007/430_2015_211] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Aloisi A, Berthet JC, Genre C, Thuéry P, Cantat T. Complexes of the tripodal phosphine ligands PhSi(XPPh2)3(X = CH2, O): synthesis, structure and catalytic activity in the hydroboration of CO2. Dalton Trans 2016; 45:14774-88. [DOI: 10.1039/c6dt02135b] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The coordination chemistry of Fe2+, Co2+and Cu+ions was explored with the ligands PhSi{CH2PPh2}3(1) and PhSi{OPPh2}3(2), so as to evaluate the impact of the electronic properties of the tripodal phosphorus ligands on the structure and reactivity of the corresponding complexes.
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Affiliation(s)
- Alicia Aloisi
- NIMBE
- CEA
- CNRS
- Université Paris-Saclay
- CEA Saclay 91191 Gif-sur-Yvette
| | | | - Caroline Genre
- NIMBE
- CEA
- CNRS
- Université Paris-Saclay
- CEA Saclay 91191 Gif-sur-Yvette
| | - Pierre Thuéry
- NIMBE
- CEA
- CNRS
- Université Paris-Saclay
- CEA Saclay 91191 Gif-sur-Yvette
| | - Thibault Cantat
- NIMBE
- CEA
- CNRS
- Université Paris-Saclay
- CEA Saclay 91191 Gif-sur-Yvette
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12
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Al-Afyouni MH, Suturina E, Pathak S, Atanasov M, Bill E, DeRosha DE, Brennessel WW, Neese F, Holland PL. Spin Isomers and Ligand Isomerization in a Three-Coordinate Cobalt(I) Carbonyl Complex. J Am Chem Soc 2015; 137:10689-99. [DOI: 10.1021/jacs.5b06078] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Malik H. Al-Afyouni
- Department
of Chemistry, University of Rochester, Rochester, New York 14618, United States
| | - Elizaveta Suturina
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 32-34, D-45470 Mülheim an der Ruhr, Germany
- Novosibirsk State University, Pirogova
Street 2, 630090 Novosibirsk, Russia
| | - Shubhrodeep Pathak
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 32-34, D-45470 Mülheim an der Ruhr, Germany
| | - Mihail Atanasov
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 32-34, D-45470 Mülheim an der Ruhr, Germany
- Institute
of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Akademy Georgi Bontchev Street 11, 1113 Sofia, Bulgaria
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 32-34, D-45470 Mülheim an der Ruhr, Germany
| | - Daniel E. DeRosha
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - William W. Brennessel
- Department
of Chemistry, University of Rochester, Rochester, New York 14618, United States
| | - Frank Neese
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 32-34, D-45470 Mülheim an der Ruhr, Germany
| | - Patrick L. Holland
- Department
of Chemistry, University of Rochester, Rochester, New York 14618, United States
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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13
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Bass HM, Cramer SA, McCullough AS, Bernstein KJ, Murdock CR, Jenkins DM. Employing Dianionic Macrocyclic Tetracarbenes To Synthesize Neutral Divalent Metal Complexes. Organometallics 2013. [DOI: 10.1021/om400043z] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Heather M. Bass
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996-1600, United
States
| | - S. Alan Cramer
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996-1600, United
States
| | - Alexander S. McCullough
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996-1600, United
States
| | - Karl J. Bernstein
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996-1600, United
States
| | - Christopher R. Murdock
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996-1600, United
States
| | - David M. Jenkins
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996-1600, United
States
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14
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Jeon IR, Calancea S, Panja A, Piñero Cruz DM, Koumousi ES, Dechambenoit P, Coulon C, Wattiaux A, Rosa P, Mathonière C, Clérac R. Spin crossover or intra-molecular electron transfer in a cyanido-bridged Fe/Co dinuclear dumbbell: a matter of state. Chem Sci 2013. [DOI: 10.1039/c3sc22069a] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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15
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Marinescu SC, Winkler JR, Gray HB. Molecular mechanisms of cobalt-catalyzed hydrogen evolution. Proc Natl Acad Sci U S A 2012; 109:15127-31. [PMID: 22949704 PMCID: PMC3458341 DOI: 10.1073/pnas.1213442109] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Several cobalt complexes catalyze the evolution of hydrogen from acidic solutions, both homogeneously and at electrodes. The detailed molecular mechanisms of these transformations remain unresolved, largely owing to the fact that key reactive intermediates have eluded detection. One method of stabilizing reactive intermediates involves minimizing the overall reaction free-energy change. Here, we report a new cobalt(I) complex that reacts with tosylic acid to evolve hydrogen with a driving force of just 30 meV/Co. Protonation of Co(I) produces a transient Co(III)-H complex that was characterized by nuclear magnetic resonance spectroscopy. The Co(III)-H intermediate decays by second-order kinetics with an inverse dependence on acid concentration. Analysis of the kinetics suggests that Co(III)-H produces hydrogen by two competing pathways: a slower homolytic route involving two Co(III)-H species and a dominant heterolytic channel in which a highly reactive Co(II)-H transient is generated by Co(I) reduction of Co(III)-H.
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Affiliation(s)
- Smaranda C. Marinescu
- Division of Chemistry and Chemical Engineering, Beckman Institute, California Institute of Technology, Pasadena, CA 91125
| | - Jay R. Winkler
- Division of Chemistry and Chemical Engineering, Beckman Institute, California Institute of Technology, Pasadena, CA 91125
| | - Harry B. Gray
- Division of Chemistry and Chemical Engineering, Beckman Institute, California Institute of Technology, Pasadena, CA 91125
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16
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Rose MJ, Bellone DE, Di Bilio AJ, Gray HB. Spectroscopic and magnetic properties of an iodo Co(I) tripodal phosphine complex. Dalton Trans 2012; 41:11788-97. [PMID: 22903546 DOI: 10.1039/c2dt31229h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of the tripodal phosphine ligand 1,1,1-tris((diphenylphosphino)phenyl)ethane (PhP3) with CoI(2) spontaneously generates a one-electron reduced complex, [(PhP3)Co(I)(I)] (1). The crystal structure of 1 reveals a distorted tetrahedral environment, with an apical Co-I bond distance of ~2.52 Å. Co(II/I) redox occurs at an unusually high potential (+0.38 V vs. SCE). The electronic absorption spectrum of 1 exhibits an MLCT peak at 320 nm (ε = 8790 M(-1) cm(-1)) and a d-d feature at 850 nm (ε = 840 M(-1) cm(-1)). Two more d-d bands are observed in the NIR region, 8650 (ε = 450) and 7950 cm(-1) (ε = 430 M(-1) cm(-1)). Temperature dependent magnetic measurements (SQUID) on 1 (solid state, 20-300 K) give μ(eff) = 2.99(6) μ(B), consistent with an S = 1 ground state. Magnetic susceptibilities below 20 K are consistent with a zero field splitting (zfs) |D| = 8 cm(-1). DFT calculations also support a spin-triplet ground state for 1, as optimized (6-31G*/PW91) geometries (S = 1) closely match the X-ray structure. EPR measurements performed in parallel mode (X-band; 0-15,000 G, 15 K) on polycrystalline 1 or frozen solutions of 1 (THF/toluene) exhibit a feature at g≈ 4 that arises from a (Δm = 2) transition within the M(S) = <+1,-1> manifold. Below 10 K, the EPR signal decreases significantly, consistent with a solution zfs parameter (|D|≈ 8 cm(-1)) similar to that obtained from SQUID measurements. Our work provides an EPR signature for high-spin Co(I) in trigonal ligation.
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Affiliation(s)
- Michael J Rose
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
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17
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Krzystek J, Ozarowski A, Zvyagin SA, Telser J. High Spin Co(I): High-Frequency and -Field EPR Spectroscopy of CoX(PPh3)3 (X = Cl, Br). Inorg Chem 2012; 51:4954-64. [DOI: 10.1021/ic202185x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- J. Krzystek
- National High Magnetic Field
Laboratory (NHMFL), Florida State University, Tallahassee, Florida 32310, United States
| | - Andrew Ozarowski
- National High Magnetic Field
Laboratory (NHMFL), Florida State University, Tallahassee, Florida 32310, United States
| | - S. A. Zvyagin
- Dresden High Magnetic Field
Laboratory (HLD), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01314 Dresden, Germany
| | - Joshua Telser
- Department of Biological, Chemical
and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United States
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18
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19
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Stauber JM, Wadler AL, Moore CE, Rheingold AL, Figueroa JS. Coordination properties of 2,5-dimesitylpyridine: an encumbering and versatile ligand for transition-metal chemistry. Inorg Chem 2011; 50:7309-16. [PMID: 21710998 DOI: 10.1021/ic201205p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
To overcome the unfavorable steric pressures associated with 2,6-disubstitution in encumbering pyridine ligands, the coordination chemistry of a 2,5-disubstituted variant, namely, 2,5-dimesitylpyridine (2,5-Mes(2)py), is reported. This diaryl pyridine shows good binding ability to a range of transition-metal fragments with varying formal oxidation states and coligands. Treatment of 2.0 equiv of 2,5-Mes(2)py with monovalent Cu and Ag triflate sources generates complexes of the type [M(2,5-Mes(2)py)(2)]OTf (M = Cu, Ag; OTf = OSO(2)CF(3)), which feature long M-OTf distances and a substrate-accessible primary coordination sphere. Combination of 2,5-Mes(2)py with Cu(OTf)(2) and Pd(OAc)(2) produces four-coordinate complexes featuring cis- and trans-2,5-Mes(2)py orientations, respectively. The four-coordinate palladium complex Pd(OAc)(2)(2,5-Mes(2)py)(2) is found to resist py-ligand dissociation at room temperature in solution, but functions as a precatalyst for the aerobic C-H bond olefination of benzene at elevated temperatures. This C-H bond activation chemistry is compared with a similar Pd-based system featuring 2,6-disubstituted pyridines. 2,5-Mes(2)py also readily supports mono- and dinuclear divalent Co complexes, and the solution-phase equilibria between such species are detailed. The coordination studies presented highlight the potential of 2,5-Mes(2)py to function as an encumbering ancillary for the stabilization of low-coordinate complexes and as a supporting ligand for metal-mediated transformations.
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Affiliation(s)
- Julia M Stauber
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, Mail Code 0358, La Jolla, California 92093-0358, USA
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Structural variation in cobalt halide complexes supported by m-terphenyl isocyanides. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2010.08.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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21
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Enamullah M. Synthetic and spectroscopic characterization of [Co(triphos)(chiral amino alcoholato)](BPh4) complexes. J COORD CHEM 2010. [DOI: 10.1080/00958970903586242] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Mohammed Enamullah
- a Department of Chemistry , Jahangirnagar University , Dhaka 1342, Bangladesh
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Grutters MM, van der Vlugt JI, Pei Y, Mills A, Lutz M, Spek A, Müller C, Moberg C, Vogt D. Highly Selective Cobalt-Catalyzed Hydrovinylation of Styrene. Adv Synth Catal 2009. [DOI: 10.1002/adsc.200900261] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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2-Pyridyl aldoxime in cobalt carboxylate chemistry: Synthesis and characterization of trinuclear complexes. INORG CHEM COMMUN 2008. [DOI: 10.1016/j.inoche.2008.07.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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24
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Beck R, Klein HF. The Crystal Structures of Trimethylphosphane supported Nickel- and Cobalt-Methyl Complexes: Octahedralmer-cis-[CoIIII(CH3)2(PMe3)3] and Square Planartrans-[NiIICl(CH3)(PMe3)2]. Z Anorg Allg Chem 2008. [DOI: 10.1002/zaac.200800254] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Mautz J, Heinze K, Wadepohl H, Huttner G. Reductive Activation oftripod Metal Compounds: Identification of Intermediates and Preparative Application. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200700873] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mautz J, Huttner G. Reductive Activation oftripod Metal Compounds: Preparative Application. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200700874] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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27
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Affo W, Ohmiya H, Fujioka T, Ikeda Y, Nakamura T, Yorimitsu H, Oshima K, Imamura Y, Mizuta T, Miyoshi K. Cobalt-Catalyzed Trimethylsilylmethylmagnesium-Promoted Radical Alkenylation of Alkyl Halides: A Complement to the Heck Reaction. J Am Chem Soc 2006; 128:8068-77. [PMID: 16771523 DOI: 10.1021/ja061417t] [Citation(s) in RCA: 173] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A cobalt complex, [CoCl2(dpph)] (DPPH = [1,6-bis(diphenylphosphino)hexane]), catalyzes an intermolecular styrylation reaction of alkyl halides in the presence of Me3SiCH2MgCl in ether to yield beta-alkylstyrenes. A variety of alkyl halides including alkyl chlorides can participate in the styrylation. A radical mechanism is strongly suggested for the styrylation reaction. The sequential isomerization/styrylation reactions of cyclopropylmethyl bromide and 6-bromo-1-hexene provide evidence of the radical mechanism. Crystallographic and spectroscopic investigations on cobalt complexes reveal that the reaction would begin with single electron transfer from an electron-rich (diphosphine)bis(trimethylsilylmethyl)cobalt(II) complex followed by reductive elimination to yield 1,2-bis(trimethylsilyl)ethane and a (diphosphine)cobalt(I) complex. The combination of [CoCl2(dppb)] (DPPB = [1,4-bis(diphenylphosphino)butane]) catalyst and Me3SiCH2MgCl induces intramolecular Heck-type cyclization reactions of 6-halo-1-hexenes via a radical process. On the other hand, the intramolecular cyclization of the prenyl ether of 2-iodophenol would proceed in a fashion similar to the conventional palladium-catalyzed transformation. The nonradical oxidative addition of carbon(sp2)-halogen bonds to cobalt is separately verified by a cobalt-catalyzed cross-coupling reaction of alkenyl halides with Me3SiCH2MgCl with retention of configuration of the starting vinyl halides. The cobalt-catalyzed intermolecular radical styrylation reaction of alkyl halides is applied to stereoselective variants. Styrylations of 1-alkoxy-2-bromocyclopentane derivatives provide trans-1-alkoxy-2-styrylcyclopentane skeletons, one of which is optically pure.
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Affiliation(s)
- Walter Affo
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Kyoto 615-8510, Japan
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Imamura Y, Mizuta T, Miyoshi K, Yorimitsu H, Oshima K. Synthesis of Coordinatively Unsaturated Cobalt(II)–Alkyl Complexes Bearing Phosphorus-bridged [1.1]Ferrocenophanes. CHEM LETT 2006. [DOI: 10.1246/cl.2006.260] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Wu B, Yuan D, Lou B, Han L, Liu C, Zhang C, Hong M. Dynamic Formation of Coordination Polymers versus Tetragonal Prisms and Unexpected Magnetic Superexchange Coupling Mediated by Encapsulated Anions in the Cobalt(II) 1,3-Bis(pyrid-4-ylthio)propan-2-one Series. Inorg Chem 2005; 44:9175-84. [PMID: 16323897 DOI: 10.1021/ic050455v] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reactions of cobalt(II) halides and flexible ligand L [L=1,3-bis(pyrid-4-ylthio)propan-2-one] under different conditions generated a series of complexes with various structural motifs ranging from tetragonal-prismatic cages to 1-3D coordination polymers. The layer diffusion of cobalt(II) chloride and L in methanol/acetone at 25 degrees C gave rise to a 3D polymer, [Co(L)2Cl2].Me2CO. At 30 degrees C, the slow diffusion of diethyl ether into the blue dimethylformamide (DMF) solution of complex 1 afforded a 1D polymer, Co(L)Cl2(DMF)2. However, at 10 degrees C, the diffusion of diethyl ether into the DMF solution of complex 1 produced a tetragonal-prismatic cage, [Co2(L)4Cl2]Cl2.Et2O.DMF.2MeOH.4H2O. The reaction of cobalt(II) bromide and L in DMF at 10 degrees C yielded a dimer, [Co2(L)4Br2]Br2.6DMF.2H2O, with a cage structure similar to. The preparation of the series of compounds indicates the subtle relationship between structures and tunable reaction conditions. It is also found that the structural motifs vary according to the ligand conformations and that the formation of tetragonal-prismatic cages and may be templated by anionic guests. Magnetic studies on complexes in a temperature range 4-300 K disclose that L is unfavorable for a long-range magnetic interaction; however, intramolecular spin-coupling constants of -19.6 and -21.5 cm-1 for and indicate rather strong magnetic superexchanges arising from the overlap of the dz2 orbitals of the cobalt(II) and pz orbitals of the encapsulated halide anions. Electron paramagnetic resonance (EPR) spectra of complexes 3 and 4 in solution and solid give information that both complexes are high-spin cobalt(II) compounds with a rhombic distortion of the axial zero-field splitting. Interestingly, the intramolecular magnetic-exchange coupling in 3 and 4 mediated by the encapsulated anion Cl- or Br- is also reflected by the EPR spectra.
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Affiliation(s)
- Benlai Wu
- State Key Laboratory of Structural Chemistry, Fujian Institute of the Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
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Castro PM, Lankinen MP, Leskelä M, Repo T. Polymerisation of Acrylates Catalysed by Methylaluminoxane Activated Ditertiary Phosphine Complexes of Iron and Cobalt Dichlorides. MACROMOL CHEM PHYS 2005. [DOI: 10.1002/macp.200400472] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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31
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Fernández D, García-Seijo MI, Sevillano P, Castiñeiras A, García-Fernández ME. Influence of the phosphine arrangement on the reactivity of palladium(II) and platinum(II) polyphosphine complexes with copper(I) chloride. Inorganica Chim Acta 2005. [DOI: 10.1016/j.ica.2005.03.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Mizuta T, Imamura Y, Miyoshi K, Yorimitsu H, Oshima K. Phosphorus-Bridged [1.1]Ferrocenophane with syn and anti Conformations. Organometallics 2005. [DOI: 10.1021/om049155w] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Oster SS, Jones WD. Synthesis, structure and reactivity of [Ir(dippe)(μ-Cl)]2, [Ir(dippe)2][Ir(dippe)Cl2] and [Ir(dippe)2]Cl. Polyhedron 2004. [DOI: 10.1016/j.poly.2004.06.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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34
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Brandt CD, Plieger PG, Kelly RJ, de Geest DJ, Kennepohl DK, Iremonger SS, Brooker S. Dinickel(II), dizinc(II) and dilead(II) complexes of a pyridazine-containing Schiff-base macrocycle. Inorganica Chim Acta 2004. [DOI: 10.1016/j.ica.2004.06.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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35
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Koo BK, Lee U. A Linear Trinuclear Cobalt(II) Complex with Acetate Bridging Ligang:Hexakisacetatodiphenanthrolinetricobalt(II). JOURNAL OF THE KOREAN CHEMICAL SOCIETY-DAEHAN HWAHAK HOE JEE 2003. [DOI: 10.5012/jkcs.2003.47.6.667] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Hitchcock P, Lee TH, Leigh G. Heterobimetallic complexes containing both iron(II) and cobalt(II). Inorganica Chim Acta 2003. [DOI: 10.1016/s0020-1693(03)00009-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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37
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Hierso JC, Amardeil R, Bentabet E, Broussier R, Gautheron B, Meunier P, Kalck P. Structural diversity in coordination chemistry of tridentate and tetradentate polyphosphines of Group 6 to 10 transition metal complexes. Coord Chem Rev 2003. [DOI: 10.1016/s0010-8545(02)00221-7] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Jenkins DM, Di Bilio AJ, Allen MJ, Betley TA, Peters JC. Elucidation of a low spin cobalt(II) system in a distorted tetrahedral geometry. J Am Chem Soc 2002; 124:15336-50. [PMID: 12487609 DOI: 10.1021/ja026433e] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have prepared a series of divalent cobalt(II) complexes supported by the [PhBP(3)] ligand ([PhBP(3)] = [PhB(CH(2)PPh(2))(3)](-)) to probe certain structural and electronic phenomena that arise from this strong field, anionic tris(phosphine) donor ligand. The solid-state structure of the complex [PhBP(3)]CoI (1), accompanied by SQUID, EPR, and optical data, indicates that it is a pseudotetrahedral cobalt(II) species with a doublet ground state-the first of its type. To our knowledge, all previous examples of 4-coordinate cobalt(II) complexes with doublet ground states have adopted square planar structure types. Complex 1 provided a useful precursor to the corresponding bromide and chloride complexes, ([PhBP(3)]Co(mu-Br))(2), (2), and ([PhBP(3)]Co(mu-Cl))(2), (3). These complexes were similarly characterized and shown to be dimeric in the solid-state. In solution, however, the monomeric low spin form of 2 and 3 dominates at 25 degrees C. There is spectroscopic evidence for a temperature-dependent monomer/dimer equilibrium in solution for complex 3. Furthermore, the dimers 2 and 3 did not display appreciable antiferromagnetic coupling that is typical of halide and oxo-bridged copper(II) and cobalt(II) dimers. Rather, the EPR and SQUID data for solid samples of 2 and 3 suggest that they have triplet ground states. Complexes 1, 2, and 3 are extremely oxygen sensitive. Thus, stoichiometric oxidation of 1 by dioxygen produced the 4-coordinate, high spin complex [PhB(CH(2)P(O)Ph(2))(2)(CH(2)PPh(2))]CoI, (4), in which the [PhBP(3)] ligand had undergone a 4-electron oxidation. Reaction of 1 with TlOAr (Ar = 2,6-Me(2)Ph) afforded an example of a 4-coordinate, high spin complex, [PhBP(3)]Co(O-2,6-Me(2)Ph) (5), with an intact [PhBP(3)] ligand. The latter two complexes were spectroscopically and structurally characterized for comparison to complexes 1, 2, and 3. Our data for these complexes collectively suggest that the [PhBP(3)] ligand provides an unusually strong ligand-field to these divalent cobalt complexes that is chemically distinct from typical tris(phosphine) donor ligand sets, and distinct from tridentate borato ligands that have been previously studied. Coupling this strong ligand-field with a pronounced axial distortion away from tetrahedral symmetry, a geometric consequence that is enforced by the [PhBP(3)] ligand, provides access to monomeric [PhBP(3)]CoX complexes with doublet rather than quartet ground states.
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Affiliation(s)
- David M Jenkins
- Division of Chemistry and Chemical Engineering, Arnold and Mabel Beckman Laboratories of Chemical Synthesis, California Institute of Technology, Pasadena, California 91125, USA
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Enamullah M, Hasegawa M, Fukuda Y, Linert W, Hoshi T. Synthesis, Characterization and Spin-Crossover Behaviors of [Co(hydroxycarboxylato)(triphos)] Complexes. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2002. [DOI: 10.1246/bcsj.75.2449] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Campos-Fernández CS, Smucker BW, Clérac R, Dunbar KR. Reactivity studies of 2,3,5,6-Tetra(2-pyridyl) pyrazine (tppz) with first-row transition metal ions. Isr J Chem 2001. [DOI: 10.1560/ywhr-r8be-2plf-7fnn] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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41
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Ara I, Berenguer J, Eguizábal E, Forniés J, Lalinde E, Martín A. Synthesis of Novel Heterotetrametallic (d6-d10-d8) Polyalkynyl Complexes Starting from Heterobimetallic Chloride-Bridged (d6-d8) Compounds. Eur J Inorg Chem 2001. [DOI: 10.1002/1099-0682(200106)2001:6<1631::aid-ejic1631>3.0.co;2-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Winterhalter U, Zsolnai L, Kircher P, Heinze K, Huttner G. Reductive Activation of Tripod Cobalt Compounds: Oxidative Addition of H−H, P−H, and Sn−H Functions. Eur J Inorg Chem 2001. [DOI: 10.1002/1099-0682(20011)2001:1<89::aid-ejic89>3.0.co;2-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Rupp R, Huttner G, Lang H, Heinze K, Büchner M, Hovestreydt E. Synthesis and π-Tweezer Properties oftripodCobalt-Bisalkynyl Compounds [CH3C(CH2PPh2)3Co(C≡CR)2] − Application to the Oxidative Coupling of Alkynyl Groups. Eur J Inorg Chem 2000. [DOI: 10.1002/1099-0682(200009)2000:9<1953::aid-ejic1953>3.0.co;2-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Rupp R, Huttner G, Kircher P, Soltek R, Büchner M. Coordination Compounds oftripodCoII andtripodCoI − Selective Substitution and Redox Behaviour. Eur J Inorg Chem 2000. [DOI: 10.1002/1099-0682(200008)2000:8<1745::aid-ejic1745>3.0.co;2-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Rupp R, Frick A, Huttner G, Rutsch P, Winterhalter U, Barth A, Kircher P, Zsolnai L. η4-Coordination of Dienes and Heterodienes to the TripodCobalt(I) Template [CH3C(CH2PPh2)3Co]+: Synthesis, Structure, and Dynamics. Eur J Inorg Chem 2000. [DOI: 10.1002/(sici)1099-0682(199903)2000:3<523::aid-ejic523>3.0.co;2-u] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Clérac R, Cotton FA, Dunbar KR, Lu T, Murillo CA, Wang X. A New Linear Tricobalt Compound with Di(2-pyridyl)amide (dpa) Ligands: Two-Step Spin Crossover of [Co3(dpa)4Cl2][BF4]. J Am Chem Soc 2000. [DOI: 10.1021/ja994051b] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rodolphe Clérac
- Contribution from The Laboratory for Molecular Structure and Bonding, Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, and Department of Chemistry, University of Costa Rica, Ciudad Universitaria, Costa Rica
| | - F. Albert Cotton
- Contribution from The Laboratory for Molecular Structure and Bonding, Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, and Department of Chemistry, University of Costa Rica, Ciudad Universitaria, Costa Rica
| | - Kim R. Dunbar
- Contribution from The Laboratory for Molecular Structure and Bonding, Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, and Department of Chemistry, University of Costa Rica, Ciudad Universitaria, Costa Rica
| | - Tongbu Lu
- Contribution from The Laboratory for Molecular Structure and Bonding, Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, and Department of Chemistry, University of Costa Rica, Ciudad Universitaria, Costa Rica
| | - Carlos A. Murillo
- Contribution from The Laboratory for Molecular Structure and Bonding, Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, and Department of Chemistry, University of Costa Rica, Ciudad Universitaria, Costa Rica
| | - Xiaoping Wang
- Contribution from The Laboratory for Molecular Structure and Bonding, Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, and Department of Chemistry, University of Costa Rica, Ciudad Universitaria, Costa Rica
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Cotton FA, Murillo CA, Wang X. Linear Tricobalt Compounds with Di-(2-pyridyl)amide (dpa) Ligands: Studies of the Paramagnetic Compound Co(3)(dpa)(4)Cl(2) in Solution. Inorg Chem 1999; 38:6294-6297. [PMID: 11671347 DOI: 10.1021/ic990944t] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Solutions of Co(3)(dpa)(4)Cl(2), where dpa = di(2-pyridyl)amide ion, in CD(2)Cl(2) were studied by NMR in the temperature range 183-303 K. The spectra show only four (1)H and five (13)C resonance signals, consistent with the D(4) symmetry of the molecules found in the solid. The magnetic susceptibility in solution was determined by the Evans method from 193 to 308 K. These observations can be modeled as an S = 1/2 to S = 5/2 spin-transition process with DeltaH = 7.7(2) kJ mol(-1) and DeltaS = 20.8(8) J K(-1) mol(-1).
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Affiliation(s)
- F. Albert Cotton
- The Laboratory for Molecular Structure and Bonding, Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, and Department of Chemistry, University of Costa Rica, Ciudad Universitaria, Costa Rica
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Heinze K, Huttner G, Schober P. Magnetic Interaction in Dinuclear Triphos−Cobalt Complexes with Co···Co Separations of 8 and 10 Å. Eur J Inorg Chem 1998. [DOI: 10.1002/(sici)1099-0682(199802)1998:2<183::aid-ejic183>3.0.co;2-p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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