Theoretical Evidence of Persistent Chirality in D3 Homoleptic Hexacoordinate Complexes with Monodentate Ligands

Authors

  • Pere Alemany Dr.,

    1. Departament de Química Física and Centre de Recerca en Química Teòrica Universitat de Barcelona Diagonal 647, 08028 Barcelona, Spain, Fax: (+34) 934021231
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  • Santiago Alvarez Prof.,

    1. Departament de Química Inorgànica and Centre de Recerca en Química Teòrica Universitat de Barcelona Diagonal 647, 08028 Barcelona, Spain
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  • David Avnir Prof.

    1. Institute of Chemistry and The Lise Meitner Minerva Center for Computational Quantum Chemistry The Hebrew University of Jerusalem Jerusalem 91904, Israel
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  • Researchers wishing to use the chirality measurement CCM programs are welcome to contact the authors.

Abstract

A theoretical study of the enantiomer interconversion pathway relevant to racemization reactions of hexacoordinate transition-metal complexes is presented based on density functional calculations. The potential-energy surface for the trigonal twist pathway of the [Zr(SH)6]2− model compound has been explored. The optimum structure reproduces, to a very good approximation, the experimental geometry of the analogous compound in which the thiolato groups have C6H4-4-OMe substituents instead of H atoms. A barrier of about 19 kcal mol−1 is estimated for the racemization of [Zr(SH)6]2− and exploratory calculations for [Zr(SC6H4-4-OMe)6]2− indicate that a larger barrier should be expected. For the chiral homoleptic organometallic complexes [ZrMe6]2− and [RhMe6]3− no significant racemization barrier is expected.

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