PREPARATION AND STUDY OF 3-COORDINATE MIXED-LIGAND COPPER(I) COMPOUNDS - MOLECULAR AND CRYSTAL-STRUCTURE OF (TRICYCLOHEXYLPHOSPHINE)(2-THIOXOHEXAMETHYLENEIMINE)COPPER(I) IODIDE

A group of mixed ligand copper(I) coordination compounds with the saturated heterocyclic thione 2-thioxohexamethyleneimine (omega-thiocaprolactam, tclH) and tricyclohexylphosphine (Pcy3) is prepared and studied. The concerted steric effects of the two bulky ligands result in the formation of three-coordinate copper(I) complexes. The iodo compound is studied by single crystal X-ray diffraction and is shown to crystallize in the P2(1)/n space group. Four monomer units with no apparent close contacts between them are present in the unit cell, the dimensions of which are a = 10.306(2), b = 15.937(2), c = 16.774(2) angstrom, and beta = 100.06(1)-degrees. The compound is trigonal planar with the Cu-S, Cu-P and Cu-I bonds equal to 2.243(2), 2.241(2) and 2.564(1) angstrom respectively. A computational study is also carried out aiming at the understanding of the factors influencing planar or pyramidal conformation in three-coordinate CuLL'L" compounds.