Issue 20, 2000

Insertion and cleavage reactions of [closo-3,1,2-Ta(NMe2)3(C2B9H11)] with nitriles, phenols and thiols; structural characterisation of N,N-dimethylamidinate ligands

Abstract

The tantalum complex [closo-3,1,2-Ta(NMe2)3(C2B9H11)] underwent insertion into the NC bond of acetonitrile and p-fluorobenzonitrile to give the N,N-dimethylacetamidinate complex [closo-3,1,2-Ta{N[double bond, length half m-dash]C(Me)NMe2}3(C2B9H11)], and p-fluoro-N,N-dimethylbenzamidinate, [closo-3,1,2-Ta{N[double bond, length half m-dash]C(C6H4F )NMe2}3(C2B9H11)], respectively. Attempted re-crystallisation of the latter from chlorinated solvents led to [closo-3,1,2-Ta{N[double bond, length half m-dash]C(C6H4F )NMe2}2Cl(C2B9H11)], in which one amidinate ligand has been replaced by a chloride. [closo-3,1,2-Ta(NMe2)3(C2B9H11)] reacts with cyclohexylisocyanide to give [Ta(NMe2)22-N(Cy)CNMe2}(C2B9H11)]. The structures of the novel N,N-dialkylamidinate complexes have been determined by single crystal X-ray diffraction, and reveal the extensive delocalisation and strong π-donor character of the amidinate ligands. The M–N bonds of [closo-3,1,2-Ta(NMe2)3(C2B9H11)] are cleaved by protic reagents, and it reacts with 2,6-dimethylphenol to give [closo-3,1,2-Ta(OC6H3Me2-2,6)3(C2B9H11)] and with benzenethiol to give the charge-compensated complex [closo-3-Ta(SC6H5)4(9-NHMe2-1,2-C2B9H10)] where the β-boron of the C2B3 face bears a NHMe2+ substituent. The structures of the last two compounds have also been determined.

Supplementary files

Article information

Article type
Paper
Submitted
19 Jun 2000
Accepted
25 Aug 2000
First published
22 Sep 2000

J. Chem. Soc., Dalton Trans., 2000, 3526-3533

Insertion and cleavage reactions of [closo-3,1,2-Ta(NMe2)3(C2B9H11)] with nitriles, phenols and thiols; structural characterisation of N,N-dimethylamidinate ligands

C. K. Broder, A. E. Goeta, J. A. K. Howard, A. K. Hughes, A. L. Johnson, J. M. Malget and K. Wade, J. Chem. Soc., Dalton Trans., 2000, 3526 DOI: 10.1039/B004862N

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