COORDINATION COMPLEXES OF GROUP (IV) HALIDES: PREPARATION AND INFRARED SPECTRA OF COORDINATION COMPOUNDS OF TITANIUM TETRACHLORIDE, TITANIUM TETRABROMIDE, ZIRCONIUM TETRACHLORIDE, AND TIN TETRACHLORIDE WITH α,ω-DINITRILES AS LIGANDS

Coordination complexes between dinitriles of dicarboxylic acids and tetrahalides of titanium, zirconium, or tin have been prepared. The analytical results and the infrared spectra indicate that on working under different experimental conditions three types of compounds are obtained: 2MX4.L—L, MX4.L—L, and MX4.2L—L where MX4 is a Lewis acid and L—L a bidentate ligand. The compounds 2MX4.L—L are explained by the formation of halogen bridging between the two metal atoms. The compounds MX4.L—L are considered to be either coordination polymers or chelates of variable ring size and the compounds MX4.2L—L, ordinary addition compounds where no chelation takes place because of the mutual interaction of the two CN groups in a dinitrile of a short chain length.