1,10-Phenanthroline and 2,2'-bipyridine chelates of higher-valent manganese

Abstract

Interaction of 1,10-phenanthroline or 2,2'-bipyridine in strongly acidic solution with the solution obtained by treating potassium permanganate with concentrated hydrochloric acid results in the separation of NN'-dihydrophenanthrolinium or NN'-dihydrobipyridinium pentachloromanganate(III). In solutions of lower acidities trichloroaquophenanthrolinemanganese(III) and trichloroaquobipyridinemanganese(III) are formed. These complexes are notable for their stability. In addition, tetrachlorobipyridinemanganese(IV) has been obtained. This decomposes when heated to a bridged manganese(111) complex, [Mn(bipy)Cl₃]₂, which has an anomalously low magnetic moment. The same complex and the corresponding phenanthroline complex were also isolated from the product of interaction of manganese dioxide and hydrochloric acid.