Five-co-ordinate, bis(catecholato) complexes of silicon(IV)
Abstract
The synthesis of a series of five-co-ordinate bis(catecholato) complexes of silicon(IV) of the type [SiRL2]– is reported, where R = Ph, Me, Et, or Prn and H2L = catechol and its derivatives. The complexes have been characterised by 1H, 13C and 29Si NMR spectroscopy in Me2SO, elemental analysis and fast atom bombardment mass spectroscopy. Complexes derived from asymmetric catechols which give rise to non-statistical, geometrical isomerism in the distorted trigonal-bipyramidal conformation have been investigated by multinuclear NMR spectroscopy. The crystal structure of the bis(3,5-dinitrocatecholato)methylsilicate anion is reported. It exhibits a slightly distorted trigonal-bipyramidal geometry. Aryl–aryl and nitro–nitro interactions play a dominant role in the solid-state packing. Mixed-ligand complexes containing different catecholato derivatives have also been studied.