Chemical nitrogen fixation by molybdenum and tungsten complexes

Nitrogen heterocycles, such as pyrroles, phthalimidines and pyridines, are synthesized starting from the ligating dinitrogen in Mo and W complexes of the type [M(N-2)(2)(L)(4)] (M = Mo, W; L = phosphine). Further, ammonia is formed from N-2 and H-2 at 55 degrees C and 1 atm by using a novel Ru/W bim etallic system, where N-2 and H-2 are activated on the W and Ru center, res pectively. (C) 1999 Elsevier Science S.A. All rights reserved.