Zinc Complexes of Aldehydes and Ketones, 4 Zinc Complexes of Chelating Aldehydes

The reactions of various zinc salts with the chelating aromatic aldehydes pyridine-2-carbaldehyde, 6-methylpyridine-2carbaldehyde, pyridine-2,6-dicarbaldehyde, and 2-dimethylaminobenzaldehyde were studied. The monoaldehydes and zinc halides yielded the tetrahedral chelate complexes ZnHal2·aldehyde. Pyridine-2-carbaldehyde also formed the octahedral bischelate complexes ZnHal2·2 aldehyde. The octahedral tris-chelate complexes [Zn(aldehyde)3]2+ were obtained from [Zn (CH3CN)6](SbCl6)2. Pyridine-2,6-dicarbaldehyde was found to be tridentate in the trigonal-bipyramidal complexes ZnHal2· aldehyde. The structural variability in this system was underlined by the identification of the two unusual complexes [(pyridine-2carbaldehyde)2(H2O)Zn-Cl-ZnCl3] and [ZnI(pyridine-2-carbaldehyde)2]2[ZnI4].