SYNTHESIS AND ELECTROCHEMISTRY OF HETEROBRIDGED GOLD(I) AND GOLD(II) COMPLEXES OF PYRIDINE-2-THIOLATE - CRYSTAL-STRUCTURES OF [AU-2(MU-(CH2)(2)PPH(2))(MU-C5H4NS)] AND [AU-2(MU-(CH2)(2)PPH(2))-(MU-C5H4NS)BR-2]

The reaction of [Au-2{mu-(CH2)(2)PPh(2)}(2)] or [Au-2(mu-L-L)(2)][ClO4](2) [L-L = dppm (Ph(2)PCH(2)PPh(2)) or dppe (Ph(2)PCH(2)CH(2)PPh(2))] with [Au-n(mu-C5H4NS)(n)] led to the heterobridged dinuclear complexes [Au-2{mu-(CH2)(2)PPh(2)}(mu-C5H4NS)] or [Au-2(mu-C5H4NS)(mu-L-L)]ClO4. The structure of [Au-2{mu-(CH2)(2)PPh(2)}(mu-C5H4NS)] has been established by X-ray crystallography and exhibits a short intramolecular gold-gold distance of 2.8623(7) Angstrom, whereas the shortest intermolecular distance is 3.984 Angstrom. The complex crystallized in the monoclinic space group P2(1)/n with a = 9.430(2), b = 8.819(2), c = 22.786(5) Angstrom, beta = 99.08(3)degrees, Z = 4. Cyclic voltammograms showed that this complex is irreversibly oxidised at a platinum electrode; chemical oxidation with the ferrocenium ion in the presence of halide or pseudohalide ions gave the gold(II) complexes [Au-2{mu-(CH2)(2)PPh(2)}(mu-C5H4NS)X(2)] (X = Cl, Br, I or SCN). The same derivatives can be obtained by oxidative addition of halogen and/or by subsequent substitution with other halogens or pseudohalogens. The complex [Au-2{mu-(CH2)(2)PPh(2)}(mu-C5H4NS)Br-2] crystallized in the triclinic space group <P(1)over bar> with a = 14.810(10), b = 14.908(10), c = 17.041(12) Angstrom, alpha = 70.20(5), beta = 69.77(5), gamma = 89.19(5)degrees, Z = 6 (at -100 degrees C). The Au-Au bond lengths in The three independent molecules are 2.564(4), 2.548(4) and 2.547(4) Angstrom.