Dynamics of formation of binuclear metal complexes : a new Cu(I) compound with N-(2-thiophenecarbonyl)-N’-(3- Cl, 4-F-phenyl) thiourea as ligand.

Abstract

Herein we report the synthesis and characterization of a new copper(I) complex with triphenylphosphine (PPh3) and N-(2- thiophenecarbonyl)-N’-(3-Cl, 4-F-phenyl)thiourea (HL), as ligands. The complex was characterized by vibrational (FTIR and FT-Raman) and multinuclear ( 1 H, 13C { 1 H}, 31P{1 H}) NMR spectroscopies. The crystalline structure of the complex was determined by single-crystal X-ray diffraction, confirming that a neutral binuclear compound, identified as [Cu(PPh3)(L-k2 -N,μ-S)]2, was obtained. The anionic thiourea ligand coordinates to the metal through the sulfur and nitrogen atoms in an unusual bidentate k2 -N,μ-S coordination mode. The complex is a dimer sited on a crystallographic center of symmetry. Each Cu2(μ-S)2 cation bridges trough the sulfur atoms of two symmetry related thiourea moieties and is also coordinated to the nitrogen atom of the thiourea ligand and the phosphorus atom from PPh3 coligand, forming a slightly distorted tetrahedral geometry. An intramolecular N H⋅⋅⋅O=C hydrogen bond is observed in the anionic ligand, forming a six-membered ring that stabilizes the N H thioamide group. Hirshfeld surface analysis shows that the molecules are connected by weak intermolecular contacts C⋅⋅⋅C, H⋅⋅⋅C and H⋅⋅⋅H which add to the stability of the crystalline packing. The in vitro cytotoxicity study of the complex indicates that it is more active against human lung carcinoma cells (A549), when compared to the free ligand.