Synthesis, X-ray crystal structure, and reactivity of the binuclear copper(I) complex [{Cu(3,5Me2-pz)(CNR)}2](R = cyclohexyl, 3,5Me2-pz = 3,5-dimethylpyrazolate) toward RNCO (R = cyclohexyl), PhNCS, COS, and CS2. N,S Co-ordination of the 3,5-dimethylpyrazolecarbodithioate anion in [Cu{3,5Me2-pz–C(S)–S}(CNR)2]

Abstract

The structure of the binuclear copper(I) complex [{Cu(3,5Me₂-pz)(CNR)}₂](1a)(R = cyclohexyl, 3,5Me₂-pz = 3,5-dimethylpyrazolate) formed by reaction of cyclohexyl isocyanide with [{Cu(3,5Me₂-pz)}_n] has been solved by single-crystal X-ray analysis. The crystals are monoclinic, space group C2/m(no. 12), with a = 14.981(2), b= 12.553(2), c= 7.469(1)Å, β= 111.17(1)°, and Z= 2. Least-squares refinement gave final values for R and R′ of 0.032 and 0.042. Each dimeric unit exhibits a Cu ⋯ Cu′ distance of 3.558(1)Å. The co-ordination around each Cu atom is planar trigonal, with the two 3,5-dimethylpyrazolate ligands bridging the metal centres and one cyclohexyl isocyanide ligand terminally bonded to each copper atom. Complex (1a) reacted with RNCO (R = cyclohexyl), PhNCS, and COS to form mononuclear derivatives of general formula [[graphic omitted](CNR)][Y = O, Z = NR, (2); Y = S, Z = NPh, (3); Y = O, Z = S, (4)]. Complexes (2)–(4) easily added a second isocyanide producing four-co-ordinated species. The reaction of CS₂ with (1a), in the presence of free RNC, gave [[graphic omitted](CNR)₂](5). A CuNS instead of CuS₂ co-ordination environment for this complex was deduced from its spectroscopic properties and confirmed by a preliminary X-ray crystal structure investigation.