Synthesis and characterization of cobaloxime dendrimer precursors

Reactions of bromobutyl or bromohexyl cobaloxime complexes with 3,5-dihydroxybenzyl alcohol in the presence of potassium carbonate gave, in both cases, mono- and di-cobalt complexes. These complexes were characterized largely by their NMR spectra. In addition, a new dimeric alkylcobaloxime complex was formed in these reactions by HBr elimination from the bromoalkyl complexes. This dimer was fully characterized and its X-ray crystal structure was determined. A zero generation dendrimer containing three cobaloxime groups was obtained by reaction of the bromobutyl cobaloxime with the core molecule 1,1,1-tris(4-hydroxyphenyl)ethane.