Transition metal complexes with thiosemicarbazide-based ligands. Part 37.* Synthesis and study of the first Thiosemi-carbazide-derived copper(I) complexes: Crystal structure of [2-(Diphenylphosphino)benzaldehyde Thiosemicarbazonato(-1)] copper(i)-nitrate-methanol solvate

Abstract

The preparation and physical characterization of two copper(I) complexes Cu(HL)NO 3 and [Cu(HL) 2 ]NO 3 ⋯ MeOH formed with a newly synthesized tridentate [S,N,P] HL = 2-(diphenylphosphino)benzaldehyde thiosemicarbazone ligand and the crystal structure analysis of the latter have been carried out. An X-ray study of [Cu(HL) 2 ]NO 3 ⋯ MeOH revealed a copper(I) ion coordinated tetrahedrally to S,N,P,P atoms donated by two HL ligands. One is tridentate [S,N,P], whereas the second HL ligand is monodentate, ligating only its phosphorus atom to the copper. The geometry around the four-coordinate Cu(I) is comparable with Cu{N,S,P,X} tetrahedra (X = N, P, or S) retrieved from the Cambridge Structural Database. In addition, with a restriction to Cu{N,P,X,X} (X = C,N,P) tetrahedra - S is excluded - ca. 60 structures against three or four cases were found to be maintained by Cu(I) ions substantiating the principal role of the phosphorus ligands in the reduction of Cu(II) to Cu(I).