Bis(triphenylphosphine)4-fluorobenzaldehyde thiosemicarbazone copper(I): Forcing chelation through oxoanions

This paper reports the synthesis and characterization of six compounds of copper(I), stabilized in its reduced state by two triphenylphosphines, in which 4-fluorobenzaldehyde thiosemicarbazone and N-methylthiosemicarbazone act as chelating through their sulfur and imino nitrogen. The three oxoanions that have been chosen, NO3−, SO42− and CH3COO−, play an important role: their oxygens are bad competitors with the imino nitrogen of the thiosemicarbazone moiety and moreover they form strong charge assisted hydrogen bondings that stabilize the neutral form of the ligand. The overall packing is determined by intermolecular phenyl–phenyl van der Waals interactions.

Six 4-fluorobenzaldehyde thiosemicarbazone and 4-fluoro-4N-methylthiosemicarbazone bis(triphenylphosphine) copper(I) complexes with different oxoanions were synthesized and characterized, for three of them the crystal structure was determined. The structures are the first reported in the literature in which a thiosemicarbazone binds as chelate on a bis(triphenylphosphine)copper(I). The role of the oxoanions is determinant in stabilizing the Z configuration without competing as ligands.Figure optionsDownload as PowerPoint slide