Synthesis of cobalt(III) and ruthenium(II) complexes of pyridine- and 4-substituted pyridine-capped mono- and bis-dioxocyclams

Abstract

A new class of 4-substituted pyridine-capped cobalt(III) dioxocyclam complexes has been synthesized. Coordination of the cobalt(III) dioxocyclams to either rhodium acetate or ruthenium phthalocyanine complexes resulted in the synthesis of polymetallic complexes that contain two or more metals. Polymetallic complexes often exhibit metal-metal interactions in the form of electrical, magnetic, and photochemical properties. However, the polymetallic cobalt(III) dioxocyclam complexes did not exhibit metal-metal interaction as assessed by cyclic voltammetry experiments. Studies were conducted towards the synthesis of bis-capped bis-dioxocyclams and their metal derivatives. Progress was hindered by the discovery that 4-substituted bis-capped bis-dioxocyclams were difficult to synthesize. Pyridine- and pyrazine-capped bis-dioxocyclams were examined for their coordination to both copper and cobalt.