SYNTHESIS OF ISOCYANIDE COMPLEXES OF ZINC - THE MOLECULAR AND CRYSTAL-STRUCTURE OF ZN(SEC(6)H(2)BU(3)(T))(2)(CNBU(T))(2)

The sterically hindered zinc chalcogenolato complexes [Zn(EAr'')(2)](2 ) (E = S, Se; Ar'' = 2,4,6-Bu(3)(t)C(6)H-2) react with 1 equivalent of tert-butylisocyanide in non-coordinating solvents to give Zn(EC(6)H(2 )BU(3)(t))(2)(CNBUt) (1,E = S;2, E = Se) as thermally stable crystalli ne adducts; the compounds are thought to be chalcogenolato-bridged dim ers. In the presence of excess isocyanide ligand the 1:2 adducts Zn(EA r'')(2)(CNBu(t))(2)(3, E = S;4, E = Se) are isolated. The compounds re present the first examples of well-characterized isocyanide complexes of zinc. The X-ray structure of 4 showed that it is monomeric with a d istorted tetrahedral coordination geometry of the metal centre, which reflects the steric requirements of the chalcogenolato and isocyanide ligands, respectively.