The chemistry of pyridinethiols and related ligands - VII. Preparation and spectroscopy of mixed-ligand copper(I) complexes: The crystal structure of first mixed-ligand dinuclear [iodo(pyridine-2-thione) (tri-p-tolylphosphine)copper(I)]2 complex

Article abstract of DOI:10.1016/S0277-5387(97)00188-5

Direct reaction of copper(I) iodide with pyridine-2-thione (C₅H₅NS) and tri-p-tolyl phosphine (p-Tol₃P) in 1:1:2 ratio in refluxing chloroform formed a product of stoichiometry, [Cul(C₅H₅NS)(p-Tol₃P)]₂ (5), whose X-ray crystal structure has been determined. It crystallises from a dichloromethane-ethanol mixture and exists as a centrosymmetric sulfur bridged dimer with distorted tetrahedral geometry about each Cu atom ; the other two positions of each Cu atom being occupied by a P atom from p-Tol₃P and a iodine atom and the central core Cu₂S² of the dimer is planar. The interatomic important parameters are: Cu - P = 2.243(3), Cu - S, 2.393(4), 2.425(4), Cu - I, 2.603(2), C - S, 1.690(12) A, Cu - S - Cu, S - Cu - S, and Cu - S - C bond angles are 85.25(13), 94.75(13) and 107.0(4) respectively. The dimer structure is stabilised by strong intramolecular N - H...T hydrogen bonds. The solution phase behaviour of 5 and other related mixed-ligand copper(I) complexes, [CuX(C₅H₅NS)L]² [X = Cl, L = p-Tol₃P (1), X = Br, L = m-Tol₃P (2), p-Tol₃P (3), X = I, L = m-Tol₃P (4)] is also studied using electronic absorption and multinuclear (¹H, ¹³C and ³¹P) NMR spectroscopy.