Syntheses and Structures of a Class of Bridged Bis(Amidinate)s and Derivatives

Abstract

A series of different types of ‘bridge’ linked bis(amidinate)s have been prepared. Reactions of a variety of linked diamines with pivaloyl chloride yielded the corresponding diamides in very high yields. Conversion of the diamides to the diimine chloride is achieved with PCl5 in CH2Cl2. Reactions of the diimine chloride with aniline or t-butyl amine yielded the bis(amidinate)s in good yields, while reaction with pyrrolyl sodium or 2,5-dimethyl pyrrolyl potassium afforded the corresponding derivatives. Their structures were characterised by NMR and HRMS, and some products were further characterised by X-ray crystal structure analysis. It was found that the locations of the hydrogen atoms within the two amidine fragments vary. The structures showed that in the phenylene-linked bis(amidinate)s, the hydrogen atoms were attached to different nitrogen atoms in the amidine groups, and in the cyclohexylene-linked bis(amidinate)s or their derivatives, the C=N of the amidine groups were conjugated with the aromatic rings.