Construction of a Novel Copper(I) Chain Polymer of Hexanuclear Cu₆(2-SC₅H₄NH)₆I₆ Cores with A New (μ₃-S) Mode of Bonding of Pyridine-2-thione and of an Unusual Triangular Cu₃I₃(dppe)₃(2-SC₅H₄NH) Cluster

The reactions of copper(I) iodide with pyridine-2-thione (2-SC₅H₄NH) in the presence of a series of diphosphane ligands, Ph₂PXPh₂P {X = (CH₂)_m, m = 1(dppm), 2 (dppe), 3 (dppp), 4 (dppb); CHCH (dppen)}, yielded an iodo-bridged hexanuclear Cu^I linear polymer, {Cu₆(μ₃-SC₅H₄NH)₄(μ₂-SC₅H₄NH)₂(I₄)(μ-I)₂}_n·2nCH₃CN (1). A similar reaction with 1,2-bis(diphenylphosphino)ethane (dppe) and 2-SC₅H₄NH yielded a triangular cluster, Cu₃I₃(dppe)₃(2-SC₅H₄NH), 2. In the chain polymer 1, three Cu(I) iodide and three 2-SC₅H₄NH ligands combined via bridging S donor atoms to form a boat-shaped trinuclear Cu₃S₃I₃ core, and two such cores combined in an inverse manner via four S-donor atoms (μ₃-S) to form a centrosymmetric hexanuclear repeat unit, Cu₆S₆I₄(μ-I)₂-, which finally formed the iodo-bridged infinite linear chain polymer 1. Linear chains are separated by the nonbonded acetonitrile molecules. Polymer 1 is the first such example of a linear chain formed by the hexanuclear Cu₆S₆I₆ core in copper chemistry as well as in metal−heterocyclic thioamide chemistry. In addition, it has the first μ₃-S mode of neutral pyridine-2-thione ever reported. In the moiety Cu₃I₃(dppe)₃ of 2, two copper(I) centers are bridged by the iodide ligands forming a Cu(μ-I)₂Cu core, while a third copper(I) center is terminally bonded to another iodide ligand. Polymer 2 is also rare, and the first triangular cluster of Cu^I with an heterocyclic thioamide.