Crystal and molecular structure of penta(4-methylbenzyl)tantalum, [Ta(CH 2C 6H 4-4Me) 5

Abstract

Reaction of the dichloride [TaCl 2(CH 2C 6H 4-4Me) 3] ( 1) (CH 2C 6H 4-4Me) 2] leads to the homoleptic 4-methylbenzyl compound [Ta(CH 2C 6H 4-4Me) 5] ( 2). The solid state structure of 2 shows a distorted square-pyramidal geometry for the central TaC 5 core. Four of the 4-methylbenzyl ligands are σ-bound to the tantalum with TaCH 2C angles of 108.4(5)−125.7(5)°, while the remaining ligand has an acute TaCH 2C angle of 90.4(5)°. In solution all alkyl groups are equivalent by 1H and 13C NMR even at −60°C, indicating facile exchange of non-equivalent alkyl groups on the NMR time-scale.