Insertion and cleavage reactions of [closo-3,1,2-Ta(NMe2)3-(C2B9H 11)] with nitriles, phenols and thiols; structural characterisation of N,N-dimethylamidinate ligands

Charlotte K. Broder, Andres E. Goeta, Judith A.K. Howard, Andrew K. Hughes, Andrew L. Johnson, John M. Malget, Ken Wade

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Abstract

The tantalum complex [closo-3,1,2-Ta(NMe2)3(C2B9H n)] underwent insertion into the NC bond of acetonitrile and p-fluorobenzonitrile to give the N,N-dimethylacetamidinate complex [closo-3,1,2-Ta{N=C(Me)NMe2}3(C2B 9H11)], andp-nuoro-N,N-dimethylbenzamidinate, [closo-3,1,2-Ta{N=C(C6H4F)NMe2} 3(C2B9H11)], respectively. Attempted re-crystallisation of the latter from chlorinated solvents led to [closo-3,1,2-Ta{N=C(C6H4F)NMe2} 2Cl(C2B9H11)], in which one amidinate ligand has been replaced by a chloride. [closo-3,1,2-Ta(NMe2)3(C2B9H 11)] reacts with cyclohexylisocyanide to give [Ta(NMe2)2{r)2-N(Cy)CNMe2}(C 2B9H11)]. The structures of the novel JV.W-dialkylamidinate complexes have been determined by single crystal X-ray diffraction, and reveal the extensive délocalisation and strong n-donor character of the amidinate ligands. The M-N bonds of [cloJo-3,1,2-Ta(NMe2)3(C2B9H) 11] are cleaved by protic reagents, and it reacts with 2,6-dimethyIphenol to give [c/oio-3,1,2-Ta(OC6H3Me2-2, 6)3(C2B9H11)] and with benzenethiol to give the charge-compensated complex [closo-3-Ta(SC6H5)4(9-NHMe 2-l,2-C2B9H10)] where the β-boron of the C2B3 face bears a NHMe2+ substituent. The structures of the last two compounds have also been determined.

Original languageEnglish
Pages (from-to)3526-3533
Number of pages8
JournalJournal of the Chemical Society, Dalton Transactions
Issue number20
DOIs
Publication statusPublished - 1 Dec 2000

ASJC Scopus subject areas

  • Chemistry(all)

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