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Dhimba G, Muller A, Lammertsma K. Chiral-at-Metal Racemization Unraveled for MX 2 (a-chel) 2 by means of a Computational Analysis of MoO 2 (acnac) 2. Chemistry 2023; 29:e202302516. [PMID: 37730887 DOI: 10.1002/chem.202302516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 09/22/2023]
Abstract
Octahedral chiral-at-metal complexes MX2 (a-chel)2 (a-chel=asymmetric chelate) can rearrange their ligands by four mechanisms known as the Bailar (B), Ray-Dutt (RD), Conte-Hippler (CH), and Dhimba-Muller-Lammertsma (DML) twists. Racemization involves their interconnections, which were computed for MoO2 (acnac)2 (acnac=β-ketoiminate) using density functional theory at ωB97x-D with the 6-31G(d,p) and 6-311G(2d,p) basis sets and LANL2DZ for molybdenum. Racemizing the cis(NN) isomer, being the global energy minimum with trans oriented imine groups, is a three step process (DML-CH-DML) that requires 17.4 kcal/mol, while all three cis isomers (cis(NN), cis(NO), and cis(OO)) interconvert at ≤17.9 kcal/mol. The B and RD twists are energetically not competitive and neither are the trans isomers. The interconnection of all enantiomeric minima and transition structures is summarized in a graph that also visualizes valley ridge inflection points for two of the three CH twists. Geometrical features of the minima and twists are given. Lastly, the influence of N-substitution on the favored racemization pathway is evaluated. The present comprehensive study serves as a template for designing chiral-at-metal MX2 (a-chel)2 catalysts that may retain their chiral integrity.
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Affiliation(s)
- George Dhimba
- Department of Chemical Sciences, University of Johannesburg, Auckland Park, Johannesburg, 2006, South Africa
| | - Alfred Muller
- Department of Chemical Sciences, University of Johannesburg, Auckland Park, Johannesburg, 2006, South Africa
| | - Koop Lammertsma
- Department of Chemical Sciences, University of Johannesburg, Auckland Park, Johannesburg, 2006, South Africa
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
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Dhimba G, Muller A, Lammertsma K. Racemization Pathway for MoO 2(acac) 2 Favored over Ray-Dutt, Bailar, and Conte-Hippler Twists. Inorg Chem 2022; 61:14918-14923. [PMID: 35980189 PMCID: PMC9516665 DOI: 10.1021/acs.inorgchem.2c00824] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chiral cis-MoO2(acac)2 racemizes via four pathways that agree with and extend upon Muetterties' topological analysis for dynamic MX2(chel)2 complexes. Textbook Ray-Dutt and Bailar twists are the least favored with barriers of 27.5 and 28.7 kcal/mol, respectively. Rotating both acac ligands of the Bailar structure by 90° gives the lower Conte-Hippler twist (20.0 kcal/mol), which represents a valley-ridge inflection that invokes the trans isomer. The most favorable is a new twist that was found by 90° rotation of only one acac ligand of the Bailar structure. The gas-phase barrier of 17.4 kcal/mol for this Dhimba-Muller-Lammertsma twist further decreases upon inclusion of the effects of solvents to 16.3 kcal/mol (benzene), 16.2 kcal/mol (toluene), and 15.4 kcal/mol (chloroform), which are in excellent agreement with the reported experimental values.
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Affiliation(s)
- George Dhimba
- Department of Chemical Sciences, University of Johannesburg, Auckland Park, Johannesburg 2006, South Africa
| | - Alfred Muller
- Department of Chemical Sciences, University of Johannesburg, Auckland Park, Johannesburg 2006, South Africa
| | - Koop Lammertsma
- Department of Chemical Sciences, University of Johannesburg, Auckland Park, Johannesburg 2006, South Africa.,Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, Amsterdam 1081 HZ, The Netherlands
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Amason EK, Rajabimoghadam K, Baughman NN, Ghareeb CR, Bourgeois SK, Keuk C, Manacsa G, Popp BV, Garcia-Bosch I, Ferrence GM, Joslin EE. Synthesis and Reactivity of Ampy-Based Ruthenium(II) Catalysts for Transfer Hydrogenation of Ketones. Organometallics 2022. [DOI: 10.1021/acs.organomet.1c00444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Edith K. Amason
- Department of Chemistry, The University of the South, Sewanee, Tennessee 22903, United States
| | | | - Notashia N. Baughman
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States
| | - C. Roland Ghareeb
- Department of Chemistry, The University of the South, Sewanee, Tennessee 22903, United States
| | - Samantha K. Bourgeois
- Department of Chemistry, The University of the South, Sewanee, Tennessee 22903, United States
| | - Channita Keuk
- Department of Chemistry, The University of the South, Sewanee, Tennessee 22903, United States
| | - Gayle Manacsa
- Department of Chemistry, The University of the South, Sewanee, Tennessee 22903, United States
| | - Brian V. Popp
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Isaac Garcia-Bosch
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Gregory M. Ferrence
- Department of Chemistry, Illinois State University, Normal, Illinois 61790, United States
| | - Evan E. Joslin
- Department of Chemistry, The University of the South, Sewanee, Tennessee 22903, United States
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Unruh T, Vöhringer P. Thermal Isomerization of [Co(acac)2(N3)(py)] in Liquid Solution Studied by Time-Resolved Fourier-Transform Infrared Spectroscopy. ACTA ACUST UNITED AC 2020. [DOI: 10.1515/zpch-2020-0006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The thermally induced stereochemical interconversion between the trans and cis isomers of [Co(acac)2(N3)(py)] in liquid solution is investigated with time-resolved Fourier-transform infrared spectroscopy. The complex is synthesized stereo-selectively in its trans-form. Upon dissolution of the trans-form, the kinetic build-up of the cis-form is evidenced by the spectro-temporal evolution of the FTIR-spectrum. The individual isomer-specific component spectra are in good agreement with calculated spectra obtained from density functional theory. The rate constants of the forward and backward reactions responsible for the trans-cis isomerization equilibrium are derived from the kinetic traces in combination with existing thermochemical data from the literature. Moreover, the temperature-dependence of the rate constants are in line with Arrhenius activation energies of (122 ± 8) kJ/mol and (109 ± 8) kJ/mol for the forward and backward reactions, respectively. DFT-calculations suggest that the stereochemical rearrangement is caused by a pyridine rebound mechanism involving penta-coordinated square-pyramidal [Co(acac)2(N3)]-intermediates.
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Affiliation(s)
- Tobias Unruh
- Institut für Physikalische und Theoretische Chemie , Rheinische Friedrich-Wilhelms-Universität Bonn , Wegelerstraße 12 , 53115 Bonn , Germany
| | - Peter Vöhringer
- Institut für Physikalische und Theoretische Chemie , Rheinische Friedrich-Wilhelms-Universität Bonn , Wegelerstraße 12 , 53115 Bonn , Germany
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5
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Karthikeyan I, Alamsetti SK, Sekar G. Isolation and Characterization of a Trinuclear Cobalt Complex Containing Trigonal-Prismatic Cobalt in Secondary Alcohol Aerobic Oxidation. Organometallics 2014. [DOI: 10.1021/om500003d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- I. Karthikeyan
- Department
of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
| | - S. K. Alamsetti
- Department
of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
| | - G. Sekar
- Department
of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
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Toganoh M, Matsuo H, Sato A, Hirashima Y, Furuta H. Synthesis and Isomerization of N-Fused Tetraphenylporphyrin Ruthenium(II) Complexes. Inorg Chem 2013; 52:9613-9. [DOI: 10.1021/ic401314a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Motoki Toganoh
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Hideaki Matsuo
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Ayumi Sato
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yuya Hirashima
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Hiroyuki Furuta
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- Center for Molecular Systems, Kyushu University, 744 Moto-oka, Nishi-ku,
Fukuoka 819-0395, Japan
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Gielen M, Nasielski J. Organometallic Compounds. XII. Topological Representations of Intramolecular Isomerizations of Five-Coordinate Structures. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bscb.19690780704] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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Brocas J, Gielen M. Group Theory and Stereoisomerism of Five-Coordinate Complexes. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bscb.19710800123] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Zampella G, Fantucci P, De Gioia L. DFT characterization of the reaction pathways for terminal- to μ-hydride isomerisation in synthetic models of the [FeFe]-hydrogenase active site. Chem Commun (Camb) 2010; 46:8824-6. [DOI: 10.1039/c0cc02821e] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Bitterwolf TE, Jeitler JR. Matrix Photolysis of Fe(allyl)(CO) 3Br. Evidence for an Unexpected Alternative Mechanism for Allyl Rotation. Organometallics 2006. [DOI: 10.1021/om050558l] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thomas E. Bitterwolf
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, and Division of Natural Sciences and Mathematics, North Idaho College, Coeur d'Alene, Idaho 83814
| | - James R. Jeitler
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, and Division of Natural Sciences and Mathematics, North Idaho College, Coeur d'Alene, Idaho 83814
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Davis AV, Firman TK, Hay BP, Raymond KN. d-Orbital Effects on Stereochemical Non-Rigidity: Twisted TiIV Intramolecular Dynamics. J Am Chem Soc 2006; 128:9484-96. [PMID: 16848486 DOI: 10.1021/ja0617946] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The isomerization dynamics of tris-catecholate complexes have been investigated by variable-temperature NMR methods, demonstrating that the intramolecular racemization of Delta and Lambda enantiomers of d0 Ti(IV) is facile and faster than that of d10 Ga(III) and Ge(IV) analogues. Activation parameters for the racemization of K2[Ti2(3)] (H(2)2 = 2,3-dihydroxy-N,N'-diisopropylterephthalamide) were determined from line shape analysis of 1H NMR spectra [methanol-d4: deltaH++ = 47(1) kJ/mol; deltaS++ = -34(4) J/mol K; deltaG++(298) = 57(3) kJ/mol; DMF-d7: deltaH++ = 55(1) kJ/mol; deltaS++ = -16(4) J/mol K; deltaG++(298) = 59(3) kJ/mol; D2O (pD* = 8.6, 20% MeOD): deltaH++ = 48(3) kJ/mol; deltaS++ = -28(10) J/mol K; deltaG++(298) = 56(3) kJ/mol]. The study of K2[Ti4(3)] (H(2)4 = 2,3-dihydroxy-N-tert-butyl-N'-benzylterephthalamide) reveals two distinct isomerization processes: faster racemization of mer-[Ti4(3)]2- by way of a Bailar twist mechanism (D3h transition state) [T(c) approximately 242 K, methanol-d4], and a slower merright harpoon over left harpoonfac [Ti4(3)]2- isomerization by way of a Rây-Dutt mechanism (C2v transition state) [T(c) approximately 281 K, methanol-d4]. The solution behavior of the Ti(IV) complexes mirrors that reported previously for analogous Ga(III) complexes, while that of analogous Ge(IV) complexes was too inert to be detected by 1H NMR up to 400 K. These experimental findings are augmented by DFT calculations of the ML3 ground states and Bailar and Rây-Dutt transition states, which correctly predict the relative kinetic barriers of complexes of the three metal ions, in addition to faithfully reproducing the ground-state structures. Orbital calculations support the conclusion that participation of the Ti(IV) d orbitals in ligand bonding contributes to the greater stabilization of the prismatic Ti(IV) transition states.
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Affiliation(s)
- Anna V Davis
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA
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16
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Gibson DH, Wu J, Mashuta MS. Synthesis and characterization of ruthenium(II) complexes bearing the bis(2-pyridylmethyl)amine ligand. Inorganica Chim Acta 2006. [DOI: 10.1016/j.ica.2005.08.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Díez J, Gamasa M, Gimeno J, Rodríguez Y, García‐Granda S. Five‐ and Six‐Coordinate Ruthenium(
II
) Complexes Containing the Bidentate Phosphane (−)‐
N
,
N
‐Bis(diphenylphosphanyl)‐(
S
)‐1‐phenylethylamine [(
S
)‐peap]: X‐ray Crystal Structure of the First 16‐Electron Ruthenium Complex Bearing a Four‐Membered Ring [RuCl{κ
2
‐
P
,
P
‐(
S)
‐peap}
2
][SbF
6
]·C
2
H
4
Cl
2. Eur J Inorg Chem 2004. [DOI: 10.1002/ejic.200300755] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Josefina Díez
- Instituto Universitario de Química Organometálica “Enrique Moles” (Unidad Asociada al CSIC), Departamento de Química Orgánica e Inorgánica, Facultad de Química, Universidad de Oviedo, 33071 Oviedo, Spain, Fax: (internat.) +34‐985‐103446
| | - M. Pilar Gamasa
- Instituto Universitario de Química Organometálica “Enrique Moles” (Unidad Asociada al CSIC), Departamento de Química Orgánica e Inorgánica, Facultad de Química, Universidad de Oviedo, 33071 Oviedo, Spain, Fax: (internat.) +34‐985‐103446
| | - José Gimeno
- Instituto Universitario de Química Organometálica “Enrique Moles” (Unidad Asociada al CSIC), Departamento de Química Orgánica e Inorgánica, Facultad de Química, Universidad de Oviedo, 33071 Oviedo, Spain, Fax: (internat.) +34‐985‐103446
| | - Yolanda Rodríguez
- Instituto Universitario de Química Organometálica “Enrique Moles” (Unidad Asociada al CSIC), Departamento de Química Orgánica e Inorgánica, Facultad de Química, Universidad de Oviedo, 33071 Oviedo, Spain, Fax: (internat.) +34‐985‐103446
| | - Santiago García‐Granda
- Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33071 Oviedo, Spain
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Santiago MO, Filho CL, Moreira IDS, Carlos RM, Queiroz SL, Batista AA. Photochemical isomerization of trans- to cis-[RuCl2(dppb)(4,4′-X2-2,2′-bipy)] (X=–H, –NO2, –Me, –COOH, –SMe, –OSMe, –Cl, –OMe) complexes. Polyhedron 2003. [DOI: 10.1016/j.poly.2003.07.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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Embedding of the Graph on a Surface with Seven Cross-caps and the Icosahedral H⊗2h Jahn–Teller Surface. ADVANCES IN QUANTUM CHEMISTRY 2003. [DOI: 10.1016/s0065-3276(03)44012-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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21
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Bickley DG, Serpone N. Permutational and mechanistic analysis of the configurational rearrangements in R2Sn(acac)2 and RClSn(acac)2 complexes. Inorg Chem 2002. [DOI: 10.1021/ic50142a027] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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Rubini PR, Rodenhueser L, Delpuech JJ. A nuclear magnetic resonance study of metal complexes of nonamethylimidodiphosphoramide. Inorg Chem 2002. [DOI: 10.1021/ic50201a004] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Darensbourg DJ. Intramolecular isomerization of an octahedral complex: bis(tri-n-butylphosphine)molybdenum tetracarbonyl. Inorg Chem 2002. [DOI: 10.1021/ic50191a003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Toupance T, Dubberley SR, Rees NH, Tyrrell BR, Mountford P. Zirconium Complexes of Diamine−Bis(phenolate) Ligands: Synthesis, Structures, and Solution Dynamics. Organometallics 2002. [DOI: 10.1021/om010982w] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thierry Toupance
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Stuart R. Dubberley
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Nicholas H. Rees
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Ben R. Tyrrell
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Philip Mountford
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
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Sander J, Hegetschweiler K, Morgenstern B, Keller A, Amrein W, Weyhermüller T, Müller I. T
‐Symmetrische Ikosaeder: eine neue Form von Chiralität bei Metallkomplexen. Angew Chem Int Ed Engl 2001. [DOI: 10.1002/1521-3757(20011119)113:22<4307::aid-ange4307>3.0.co;2-#] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jürgen Sander
- Universität des Saarlandes, Anorganische Chemie Postfach 15 11 50, 66041 Saarbrücken (Deutschland) Fax: (+49) 681‐302‐2663
| | - Kaspar Hegetschweiler
- Universität des Saarlandes, Anorganische Chemie Postfach 15 11 50, 66041 Saarbrücken (Deutschland) Fax: (+49) 681‐302‐2663
| | - Bernd Morgenstern
- Universität des Saarlandes, Anorganische Chemie Postfach 15 11 50, 66041 Saarbrücken (Deutschland) Fax: (+49) 681‐302‐2663
| | - Alice Keller
- Universität des Saarlandes, Mathematik Postfach 15 11 50, 66041 Saarbrücken (Deutschland)
| | - Walter Amrein
- Laboratorium für Organische Chemie, ETH‐Zentrum 8092 Zürich (Schweiz)
| | - Thomas Weyhermüller
- Max‐Planck‐Institut für Strahlenchemie Postfach 10 13 65, 45413 Mühlheim an der Ruhr (Deutschland)
| | - Iris Müller
- Institut für Analytische Chemie Postfach 10 21 48, 44721 Bochum (Deutschland)
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26
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Sander J, Hegetschweiler K, Morgenstern B, Keller A, Amrein W, Weyhermüller T, Müller I. T-Symmetrical Icosahedra: A New Type of Chirality in Metal Complexes. Angew Chem Int Ed Engl 2001; 40:4179-4182. [DOI: 10.1002/1521-3773(20011119)40:22<4179::aid-anie4179>3.0.co;2-c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2001] [Indexed: 11/08/2022]
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Soubra C, Oishi Y, Albright TA, Fujimoto H. Intramolecular rearrangements in six-coordinate ruthenium and iron dihydrides. Inorg Chem 2001; 40:620-7. [PMID: 11225102 DOI: 10.1021/ic0006089] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Molecular orbital calculations at the ab initio level are used to study polytopal rearrangements in H2Ru(PH3)4 and H2Fe(CO)4 as models of 18-electron, octahedral metal dihydrides. It is found that, in both cases, the transition state for these rearrangements is a dihydrogen species. For H2Fe(CO)4, this is a square pyramidal complex where the H2 ligand occupies an apical position and is rotated by 45 degrees from its original orientation. This is precisely analogous to the transition state for Fe-olefin rotation in (olefin)Fe(CO)4 complexes and has a very similar electronic origin. Another transition state very close in energy is found wherein the basic coordination geometry is a trigonal bipyramid and the H2 ligand is coordinated in the axial position. For H2Ru(PH3)4, the former stationary point lies at a much higher energy and the latter clearly serves as the transition state for hydride exchange. The reason for this difference is discussed along with the roles of electron correlation in the two compounds.
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Affiliation(s)
- C Soubra
- Department of Chemistry, University of Houston, Houston, Texas 77204-5641, USA
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Yandulov DV, Huang D, Huffman JC, Caulton KG. Structural distortions in mer-M(H)3(NO)L2 (M = Ru, Os) and their influence on intramolecular fluxionality and quantum exchange coupling. Inorg Chem 2000; 39:1919-32. [PMID: 11428112 DOI: 10.1021/ic991452j] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecules of the type mer-M(H)3(NO)L2 [M = Ru (1), Os (2); L = PR3] are characterized on the basis of 1H NMR T1min values and IR spectra as pseudo-octahedral trihydrides significantly distorted by compression of the cis H-M-H angles to approximately 75 degrees. The distortion, uncharacteristic of six-coordinate d6 complexes, is rationalized with DFT (B3LYP) calculations as being driven by increased H-to-M sigma donation and by the exceptional pi-accepting ability of linear NO+. In both 1 and 2, hydrides undergo intramolecular site exchange with delta HHH++(1) = 10-11 kcal/mol and delta HHH++(2) = 16-20 kcal/mol, depending on L, whereas for mer-Ru(H)3(NO)(PtBu2Me)2 (1b), moderate exchange couplings (up to 77 Hz) are featured in the low-temperature 1H NMR spectra, in addition to chemical exchange. On the basis of experimental and theoretical results, a dihydrogen intermediate is suggested to mediate hydride site exchange in 1. The cis H-M-H distortion shortens the tunneling path for the exchanging hydrides in 1, thereby increasing the tunneling rate; diminishes the "conflict" between trans hydrides in the mer geometry; and decreases the nucleophilicity of the hydrides. The generality of the observed structural distortion and its dependence on the ligand environment in late transition metal tri- and dihydrides are discussed. A less reducing metal center is generally characterized by greater distortion.
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Affiliation(s)
- D V Yandulov
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001, USA
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Xi R, Wang B, Abe M, Ozawa Y, Kinoshita I, Isobe K. Tetranuclear Mo2Rh2Complexes Obtained from Reactions between Triple Cubane-Type Oxide Cluster [(Cp*Rh)4Mo4O16] (Cp* =η5-C5(CH3)5) and Methanethiol: [{Cp*Rh(μ-SCH3)3MoO2}2(μ-O)] and [{Cp*Rh(μ-SCH3)3MoO}2(μ-X)(μ-Y)] (X, Y = O and X = O, Y = S). Synthesis, X-Ray Structures, and Dynamic Behavior in Nonaqueous Media. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1999. [DOI: 10.1246/bcsj.72.1985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Piguet C, Bernardinelli G, Hopfgartner G. Helicates as Versatile Supramolecular Complexes. Chem Rev 1997; 97:2005-2062. [PMID: 11848897 DOI: 10.1021/cr960053s] [Citation(s) in RCA: 1339] [Impact Index Per Article: 49.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Claude Piguet
- Department of Inorganic, Analytical and Applied Chemistry and the Laboratory of X-ray Crystallography, University of Geneva, 30 quai Ernest Ansermet, 1211 Geneva 4, Switzerland, and Pharma Division, F. Hoffmann-La Roche Ltd CH-4070 Basle, Switzerland
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Bakhmutov VI, Visseaux M, Baudry D, Dormond A, Richard P. Synthesis, NMR Study, and Reactivity of Isomeric Early-Late Heterobimetallic Dihydrides. X-ray Crystal Structure of (PPh(3))HRu(&mgr;-H)(&mgr;-PMe(2)C(5)Me(4))(2)(&mgr;-Cl)ZrCl. Inorg Chem 1996; 35:7316-7324. [PMID: 11666924 DOI: 10.1021/ic960073c] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The new isomeric ruthenium/zirconium dihydrides of the formula (PPh(3))HRuH(&mgr;-PMe(2)Cp)(2)ClZrCl (1, 2) (Cp = C(5)Me(4)) have been characterized by elemental analysis and NMR ((1)H, (31)P and (1)H relaxation data). Complex 1, stabilized by Cl and H bridges, has been isolated from the room temperature reaction between RuH(2)(H(2))(PPh(3))(3) and (PMe(2)Cp)(2)ZrCl(2). The X-ray crystallographic study of 1 revealed a bimetallic complex. The six-coordinate Ru atom and the five-coordinate Zr atom are held together by two bifunctional phosphinocyclopentadienyl ligands and by H and Cl bridges. Crystal data for 1: monoclinic space group P2(1)/c, a = 13.901(2) Å, b = 18.205(6) Å, c = 16.633(3) Å, beta = 92.43(1) degrees, V = 4206 Å(3), Z = 4, d(calc) = 1.472 g cm(-)(3), R(F) = 0.056, R(w)(F) = 0.058. Complex 2 with two H bridges and terminal Cl ligands at Ru and Zr has been obtained by an irreversible isomerization of 1 in the presence of HNEt(3)BPh(4). This transformation has been proposed to occur through slow protonation of one of the phosphorus ligands with the five-coordinate Ru center formed by undergoing rapid pseudorotation. Complexes 1 and 2 do not react with H(2), N(2), or 3,3-dimethyl-but-1-ene. Treatment of 1 with 1 equiv of NaHBEt(3) in C(6)D(6) gives a mixture of new trihydrides (PPh(3))HRu(&mgr;-Cl)(&mgr;-H)(&mgr;-PMe(2)Cp)(2)ZrH (3) and (PPh(3))HRu(&mgr;-H)(2)(&mgr;-PMe(2)Cp)(2)ZrCl (4). Complex 3 transforms to 4 upon standing in solution for a period of several days. Under the same conditions, complex 2 leads smoothly to trihydride 4. Both trihydrides are new and have been characterized by (1)H, (31)P NMR, and (1)H NMR relaxation data. Complexes 1 and 4 are fluxional in solution at room temperature, showing hydride exchange between the terminal and bridging positions. The variable-temperature (1)H NMR spectra allowed determinations of the DeltaG() values of 16.4 (313 K, THF-d(8)) and 13.5 kcal/mol (295 K, toluene-d(8)) for the exchange in complexes 1 and 4, respectively. Possible exchange mechanisms have been discussed. Complex 2 is rigid on the NMR time scale.
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Affiliation(s)
- Vladimir I. Bakhmutov
- Institute of Organo-Element Compounds, Russian Academy of Sciences, 28 Vavilova, Moscow, Russia, and Laboratoire de Synthèse et d'Electrosynthèse Organométallique (URA 1685) and UFR Sciences et Techniques, Faculté des Sciences, 6 Boulevard Gabriel, 21000 Dijon, France
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Nakata R, Yano M, Ochi Y, Hatanaka N, Oki H. Kinetics and Thermodynamics of the Racemization of Tris(L-valinato)chromium(III) Complexes in N, N-Dimethylformamide. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1996. [DOI: 10.1246/bcsj.69.1261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
We have recently developed a 3-dimensional Hückel method for cluster compounds. The method uses a set of approximations for Coulomb, resonance, and overlap integrals very similar to those employed in the familiar 2-dimensional Hückel theory for the pi electrons of planar conjugated hydrocarbons. The method can be adapted to heteroatomic clusters by introducing heteroatomic Coulomb integrals, alpha(Y) = alpha(X) + hbeta, whereh is a parameter for heteroatom Y. In this paper, we use the 3-dimensional Hückel method to study the properties of the closo-carboranes, C(2)B(n)()(-)(2)H(n)(). We calibrate the method by choosing a value of the heteroatomic parameter h that distinguishes positional isomers by energy and gives them relative energies in rough agreement with those established by observation and ab initio calculations. We obtain modest improvement in matching ab initio relative energies of isomers by means of a three-parameter, first-order perturbation treatment. We use the calibrated method to evaluate various mechanisms proposed for the isomerizations of C(2)B(4)H(6), C(2)B(5)H(7), and C(2)B(6)H(8), all of which have been observed to undergo intramolecular isomerizations. Rearrangements of C(2)B(6)H(8) have been satisfactorily explained by a single-DSD (diamond-square-diamond) process. Those for C(2)B(5)H(7) require at least two DSD processes, concerted, consecutive, or overlapping. Several different mechanisms have been proposed for the rearrangement of C(2)B(4)H(6). In evaluating intermediate and transition state structures, the 3-dimensional Hückel method gives higher energies to those structures with a larger number of nontriangular faces, a plausible conclusion except that occasionally it is wrong. In comparison with ab initio results, the 3-dimensional Hückel method fails to give low energies for classical structures.
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Affiliation(s)
- Benjamin M. Gimarc
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
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Bruce King R. Mathematical methods in coordination chemistry: topological and graph-theoretical ideas in the study of metal clusters and polyhedral isomerizations. Coord Chem Rev 1993. [DOI: 10.1016/0010-8545(93)80043-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Hoshino Y, Takahashi R, Shimizu K, Satô GP, Aoki K. A Least-Squares Method for Computing Rate Constants of Reversible, First-Order, Triangular Network Reactions and Its Application to the Intermolecular Rearrangements of Acetylacetonatobis(4,4,4-trifluoro-1-phenyl-1,3-butanedionato)ruthenium(III). BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1989. [DOI: 10.1246/bcsj.62.993] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Bottomley LD, Clark RJ, Berger TG. Intramolecular isomerization of chromium and Tungsten bis(trifluorophosphine)carbonyls. Polyhedron 1989. [DOI: 10.1016/s0277-5387(00)80346-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Vdovenko S, Guerus I, Yagupolskii Y. Transition-metal complexes with σ-bonded fluorine-containing groups. J Organomet Chem 1986. [DOI: 10.1016/0022-328x(86)80010-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Rabinovich A, Dashevskii(dec.) V. The study of structural non-rigidity of molecules with double bonds in the main chain. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/0032-3950(84)90457-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Lindoy LF. Nuclear magnetic resonance studies of coordination metal complexes using lanthanide shift reagents. Coord Chem Rev 1983. [DOI: 10.1016/0010-8545(83)85003-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Schenk WA, Müller H. Carbonyl-Monoolefin-Derivate des Chroms, Molybdäns und Wolframs, III. Darstellung und Reaktivität von Tricarbonyl-Chelatphosphan-Olefin-Komplexen. ACTA ACUST UNITED AC 1982. [DOI: 10.1002/cber.19821151114] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Dostovalova VI, Minacheva MK, Nikolaeva TD, Zhdanov SI, Fedorov LA, Brainina �M. Structure of cyclopentadienyl chelate complexes of zirconium of the types Cp2Zr(chel)X and Cp2Zr(chel)X�H2O. Russ Chem Bull 1981. [DOI: 10.1007/bf00949717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bruce King R. Chemical applications of group theory and topology. X. Topological representations of hyperoctahedrally restricted eight-coordinate polyhedral rearrangements [1]. ACTA ACUST UNITED AC 1981. [DOI: 10.1007/bf00574434] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Chemical applications of topology and group theory. 11. Degenerate edges as a source of inherent fluxionality in deltahedra. Inorganica Chim Acta 1981. [DOI: 10.1016/s0020-1693(00)90490-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Kummer D, Balkir A, Köster H. Beiträge zur chemie der halogensilan-addukte XV. 2,2′-bipyridin- und 1,10-phenanthrolin-komplexe von halogendisilanen und Si3Cl8. J Organomet Chem 1979. [DOI: 10.1016/s0022-328x(00)87859-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Influence of the oxo and peroxo ligands on the stereolability of chelated hexa- and heptacoordinated species of transition metals. Inorganica Chim Acta 1979. [DOI: 10.1016/s0020-1693(00)89460-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hasenpusch W, Preetz W. Platzwechselvorg�nge der Liganden in festen Komplexsalzen. V. Photochemische cis/trans-Umlagerung in festen Chloro-Jodo-Osmaten(IV). Z Anorg Allg Chem 1977. [DOI: 10.1002/zaac.19774320112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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