Electrospray mass spectrometry characterization of ionic silver(I) and gold(I) complexes of the ligand L = 1-benzyl-2-imidazolyl-diphenylphosphine. Counterion influence in the ionization processes and crystal structure determination of [Ag2L3][CF3SO3]2.

One of the most discussed and studied aspects of the silver(I) coordination complexes chemistry is the influence of the counterions in the solid state structures and in the ligand exchange reactions occurring in solution; this kind of chemistry is pretty rare in the gold(I) coordination derivatives. Some silver(I) and gold(I) complexes of the type L2M2X2 (where L is 1-benzyl-2-imidazolyl diphenylphosphine I, M = Ag, X = BF4 II; X=NO3 III, X=CF3SO3 IV, X = BAr4 V), L3M2X2 (M = Ag, X =NO3 VI, X=BF4 VII, X = BAr4 VIII, X =CF3SO3 IX), LAuCl (X), L2Au2X2 (X = BF4, XI) and L2AuBF4 (XII) have been synthesized. In the paper is reported the unprecedented structure of IX. From the analysis of the structures, it can be argued that in the silver(I) complexes the counterions deeply affect the structure by strongly interacting with the metal centres. In addition it is also reported the study of these complexes by the ESI mass spectrometry with the target of both studying the counterion effect in the ionization process, and to characterize the above described complexes by this new soft mass spectrometry technique.