Trimethylarsine oxide and trimethylarsine sulphide complexes with iron(II) and nickel halides

Abstract

Trimethylarsine sulphide forms tetrahedral iron and nickel complexes of types ML₂X₂ and [ML₄](ClO₄)₂. Spectroscopic and magnetic data on the arsine oxide compounds ML₂X₂(M = Fe, Ni; X = Cl, Br, NCS) show them to be bridged octahedral compounds. Cobalt will also produce octahedral isomers of this class in addition to the known tetrahedral derivatives. The large reduction in the ν(As–O) frequencies in the octahedral compounds points to bridging through oxygen rather than through halogen or thiocyanate. Several relatively less stable trimethylphosphine oxide derivatives are reported.