Chemical and spectroscopic studies in metal β-diketonates. I. Preparation and study of halogenate metal acetylacetonates

Abstract

Introduction of chlorine, bromine, and iodine into the rings of acetylacetonates of Cu^II, Ni^II, Al^III, Cr^III, Fe^III, Co^III, and VO^IV has been effected by direct halogenation under varied but carefully controlled electrophilic substitution reaction conditions (usually applicable to aromatic systems) such as with chlorine, N-chlorosuccinimide (NCS), bromine, N-bromosuccinimide (NBS), or iodine monochloride in chloroform, acetic acid, or methanol solvent. Infrared and ultraviolet spectroscopic data on the metal chelates and their halogen derivatives have been obtained with a view to studying possible changes brought about by such substitution in the acetylacetonate rings of different metals. The v(C=C) and v(C=O) values were both found to show a linear relationship with the mass numbers of the substituents as also with the third ionization potential of trivalent metals. The halogenation of these chelates apparently results in an extension of conjugation.