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 COORDINATION OF THE 3,5-DIMETHYLPYRAZOLECARBODITHIOATE ANION IN [CU(3,5ME2-PZ-C(S)-S)(CNR)2]

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 [Cu{3,5Me2-pz-C(Y)-Z}(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 [Cu{3,5Me2-pz-C(S)-S}(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.