Synthesis and Reactivity of Tungsten− and Molybdenum−Dinitrogen Complexes Bearing Ferrocenyldiphosphines toward Protonolysis

Novel tungsten− and molybdenum−dinitrogen complexes bearing 1,1′-bis(diethylphosphino)ferrocenes as auxiliary ligands have been prepared and characterized crystallographically. Reactions of these complexes with an excess amount of sulfuric acid in methanol at room temperature yield ammonia in good yields. This result is in sharp contrast to the previous result that protonolysis of tungsten− and molybdenum−dinitrogen complexes bearing conventional diphosphines such as 1,2-bis(diphenylphosphino)ethane does not produce ammonia. Reactions of the dinitrogen complexes with 2 equiv of trifluoromethanesulfonic acid give the corresponding hydrazido complexes as intermediates. Molecular structures of these hydrazido complexes have been determined by X-ray analysis.