2,3,5-Metallotriazoles: Amphoteric Mesoionic Chelates from Nitrosoguanidines.

Soluble nitrosoguanidine- and -methylnitrosoguanidine-based metallotriazole complexes of ruthenium(II) monocarbonyls have been prepared and characterized. Both nitrosoguanidines prove to be strong chelates with the formally π-accepting nitroso nitrogen binding to carbon monoxide and a π-donating amide to the CO. The resulting ensemble consists of ruthenium examples of 1-metallo-2,3,5-triazoles.