Organotin coordination complexes of 2,2′-bipyridine N,N′-dioxide

Abstract

V.G. Kumar Das Department of Chemistry, University of Malaya, Kuala Lumpur, Malaysia (Received 1 September 1972; The ligand, 2,2'-Bipyridine N,N'-Dioxide (BipyO2) , is known to yield isolable complexes with transition metal ions (I, 2) but organometalllc &ocep~ors do not appear to have been investigated. We wish to report here briefly on the isolation of some organotin chloride and isothiocyanate complexes as well as of complexes of organotin cations and of diphenyllead dichloride in which the potentiality of BipyO 2 both as a chelating group and as a bridging ligand seems indicated ( T a b l e I). Although the coordination chemistry of R3SnX and R2SnX 2 compounds is rich in examples of complexes involving neutral mono and bidentate ligands, very few exm, ples have been documented which involve the bidentate ligands in a bridging capacity. Recent examples include (Me3SnNCS)n.Bipy (3) and ~Oct2Sn(NqS)~n. Bipy (4) where n I, 2 and EPh2Sn(NCO)2 32.Bipy (5) for which there appear little evidence favouring ionic formulations. For these bridged complexes pentacoordinatior of tin has been suggested. Complexes (I) and (II) indicate a preference for the ligand to yield bridged complexes with Ph3SnX , but do not, however, preclude the possibility of I:I complex formation of the llgand with other trlorganotin (IV) systems. For the I:I complexes of R2SnX 2 with BipyO 2 which conduct negligibly in ethanol (vide infra) chelate structures with octahedral covalency of tin appear plausible although non-chelate structures involving pentacoordinated tin (monomeric) or hexacoordinated tin (polymeric) also merit attention as possible alternatives. The tetraphenylborate complexes (VI-VlII), however, raise the possibility of a chelating BipyO 2 since they may be regarded as analogous to the