HETEROBRIDGED DINUCLEAR GOLD(I) AND GOLD(II) COMPLEXES WITH XANTHATE LIGANDS - X-RAY STRUCTURES OF [AU-2(MU-(CH2)(2)PPH(2))(MU-(S2COPR)-PR-I)] AND [AU-2(MU-(CH2)(2)PPH(2))(MU-S(2)COME)BR-2]

The reaction of [Au-n(S(2)COR)(n)] (R = Me, Et, Pr-i) with [Au-2(mu-L-L)(2)](2+) (z = 0, L-L = CH2-PPh(2)CH(2); z = 2, L-L = PPh(2)CH(2)PPh(2), PPh(2)CH(2)CH(2)PPh(2)) leads through a bidentate ligand transfer to heterobridged dinuclear complexes [Au-2(mu-S(2)COR)(mu-L-L)](2+) (z = 0, 1). The crystal structure of[Au-2{mu-(CH2)(2)PPh(2)}(mu-(S2COPr)-Pr-i)] shows a short intramolecular gold-gold distance of 2.8809(9) Angstrom. It crystallizes in the monoclinic space group P2(1)/c with a = 8.571(3) Angstrom, b = 10.219(4) Angstrom, c = 23.210(6) Angstrom, beta = 97.37(3)degrees, and Z = 4 (at -100 degrees C). The oxidative addition of halogen affords the corresponding neutral gold(II) complexes containing xanthate ligands [Au-2{mu-(CH2)(2)PPh(2)}(mu-S(2)COR)X(2)] (R = Me, Et, Pr-i; X = Cl, Br, I). [Au-2{mu-(CH2)(2)PPh(2)}(mu-S(2)COMe)Br-2] crystallizes in the triclinic space group P $$($) over bar 1 with a = 12.917(4) Angstrom, b = 13.864(3) Angstrom, c = 15.975(5) Angstrom, alpha = 106.05(2)degrees, beta = 96.27(2)degrees, gamma = 113.78(2)degrees, and Z = 4 (at -100 degrees C). The molecule possesses the general features of dinuclear gold(II) complexes, including a short gold-gold bond of 2.566(1) Angstrom.