Studies on metal carboxylates. Part X. The reactions of Group VI hexacarbonyls with pyridinecarboxylic acids. Complexes of chromium(III), molybdenum(III), and tungsten-(0), -(I), and -(IV)

Abstract

The reactions of the hexacarbonyls of chromium, molybdenum, and tungsten with pyridine-2-carboxylic acid(picH) in boiling methanol afford the species [Cr(pic)₃], [Mo(pic)₃]·MeOH, and [W(pic)₄]. The diamagnetic tungsten(I) complex [{W(CO)₃(pic)}_n] has also been isolated and found to be a very useful intermediate for the synthesis of a variety of tungsten carbonyl complexes of 2,2′-bipyridyl and 1,2-bis(diphenylphosphino) ethane. The reaction of [W(CO)₆] with pyridine-3- and -4-carboxylic acids(nicH and isonicH, respectively) proceeds in an analogous fashion to that observed with pyridine, namely substitution without oxidation.