Copper-63,65 nuclear quadrupole resonance studies of copper(I) complexes with sulfur-containing ligands. Part 2. Bis(1-alkylimidazolidine-2-thione)copper(I) iodides and related compounds

Abstract

The ⁶³Cu NQR resonances frequencies of ten three-co-ordinated copper(I) complexes, in each of which at least two of the ligands are thiones, have been determined. The Zeeman splitting of the ⁶³Cu NQR spectrum of a single crystal of bis(tetrahydro-1H-pyrimidine-2-thione)copper(I) chloride yields the value of 0.36(2) for the asymmetry parameter with the field-gradient z axis perpendicular to the CuS₂Cl plane and the y axis along the Cu–Cl bond. The crystal structure of a representative member of these complexes, bis(1-propylimidazolidine-2-thione)copper(I) iodide, confirms the three-co-ordination of the Cu^I. When one of the ligands is a halogen atom the results confirm the previously reported trend that, for a given ligand, the ⁶³Cu NQR resonance frequencies of the complexes [CuL₂X] are in the order Cl > Br > I. For two of the complexes the temperature dependence of the NQR frequency indicates that a phase change occurs in the range 77–300 K.