Studies in the Stereochemistry of Zinc(II). I. Derivatives of Bis(acetyl-acetonato)zinc(II)

Abstract

The compound melting at 138° and for long supposed to be anhydrous bis(acetylacetonato)zinc(II) is shown to be the monohydrate. The anhydrous compound has also been obtained, melting at 152°; and adducts are described with one and two molecules of pyridine or 4-methylpyridine, one molecule of 2-methylpyridine, and two molecules of ammonia. Molecular weight determinations in benzene and triphenylmethane show that with the exception of the anhydrous compound which is monomeric, the predominant species in solution are five-coordinate. Differences in the stereochemical behaviour of zinc in these compounds from the behaviour of cobalt(II) and nickel(II) in corresponding compounds are interpreted in terms of crystal-field stabilization of octahedral complexes of the latter ions.