CRYSTAL-STRUCTURE AND CHEMICAL-PROPERTIES OF [CU(3,5ME2-PZ-C(S)-S)(CNR)2] (R = CYCLOHEXYL, 3,5ME2-PZ = 3,5-DIMETHYLPYRAZOLATE)

The binuclear copper(I) complex [Cu(3,5Me2-pz)(CNR)]2 (R = cyclohexyl; 3,5Me2-pz = 3,5-dimethylpyrazolate) (A) reacts with CS2 in the presence of free RNC, yielding the 3,5-dimethylpyrazole-carbodithioate derivative [Cu(3,5Me2-pz-C(S)-S)(CNR)2] (I). In the absence of free RNC, A gives [Cu2(3,5Me2-pz-C(S)-S)2(CNR)] (II). The action of an excess of RNC on II afforded I. One RNC ligand in complex I is easily replaced by PPh3 producing [Cu(3,5Me2-pzC(S)-S)(CNR)(PPh3)] (III). The crystal and molecular structure of I has been elucidated by single crystal X-ray analysis. Its unit cell has dimensions a = b = 9.806(1), c = 23.734(6) angstrom, space group P4(1). The structure was solved with conventional Patterson and difference Fourier methods, and refined to R = 0.040 for 1134 reflections having I > 3-sigma(I). By treating I with ethyl bromide, the pyrazole carbodithioate anion is displaced and recovered as the corresponding ethyl ester, 3,5Me2-pzCS2Et.