Transition metal dicarbollide complexes: Synthesis, molecular, crystal and electronic structures of [M(C2B9H11)(NMe2)3] (M = Nb or Ta) and their insertion reactions with CO2 and CS2

Andrei S. Batsanov, Andrei V. Churakov, Judith A.K. Howard, Andrew K. Hughes, Andrew L. Johnson, Andrew J. Kingsley, Ivan S. Neretin, Ken Wade

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The homoleptic amides [M(NMe2)5] (M = Nb 1 or Ta 2; the latter is characterised by a structural study) reacted with the carborane nido-C2B9H13 to eliminate two equivalents of HNMe2 and generate the dicarbollide half-sandwich tris(dimethylamide) complexes [M(C2B9H11)(NMe2)3] (M = Nb 3 or Ta 4). The crystal structures of isomorphous 3 and 4 have been determined and reveal two NMe2 ligands in a vertical orientation and the third one in a horizontal orientation with respect to the η5-co-ordinated face of the C2B9H11 ligand. The electronic factors responsible for the amide ligand orientations in these complexes are explored using qualitative MO arguments. Complexes 3 and 4 reacted with CO2 and CS2 to yield the tris(carbamate) [M(C2B9H11)(O2CNMe2) 3] (M = Nb 5 or Ta 7) and tris(dithiocarbamate) [M(C2B9H11)(S2CNMe2) 3] (M = Nb 6 or Ta 8) complexes, respectively. The crystal structures of 6 and 7 show two (dithio)carbamate ligands in horizontal and one in vertical orientation, demonstrating the similarity between the σ,π-donor frontier orbitals of the ligands NMe2 and X2CNMe2 in 4 and 6 or 7 respectively.

Original languageEnglish
Pages (from-to)3867-3875
Number of pages9
JournalJournal of the Chemical Society - Dalton Transactions
Issue number21
Publication statusPublished - 7 Nov 1999

ASJC Scopus subject areas

  • Chemistry(all)

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