Synthesis, structure, and reactions of binuclear gold(I) complexes containing two different bridging ligands

The binuclear cycloaurated compounds [Au-2(mu -C6H3-2-PPh2-n-Me)(2)] (n = 5 , 1a; n = 6, 1b) react with the digold(I) complexes [Au-2(mu -(S2CNBu2)-Bu- n)(2)] and [Au-2(mu -dppm)(2)](PF6)(2) to give heterobridged dinuclear comp lexes [Au-2(mu -C6H3-2-PPh2-n-Me)(mu -dppm)]PF6, (n = (n = 5, 5a; n = 6, 5b )(-) and [Au-2(mu -C6H3-2-PPh2-n-Me)(mu -dppm)]PF6, (n = 5, 9a; n = 6, 9b), respectively. Complex 5a exists in the solid state as an infinite zigzag c hain of dimeric units with intramolecular Au-Au separations of 2.8331(3) an d 2.8243(3) A for independent molecules and intermolecular Au-Au separation s of 3.0653(3) And 3.1304(3) A. Both 5a and 5b undergo oxidative addition w ith halogens to (S2CNBu2)-Bu-n)] [n = 5, give the heterovalent, gold(I)-gol d(III) compounds [XAuI(mu -2-Ph2PC6H3-n-Me)(AuX)-X-III(eta (2)-(S2CNBu2)-Bu -n)] [n = 5 X = Cl (6a), I (8a); n = 6, X = Cl (6b), Br (7b), I (8b)]. Comp ound 8a has been shown by X-ray crystallography to contain a gold(I) atom c oordinated in a planar array by bidentate, chelating di-n-butyldithiocarbam ate, iodide, and the cr-aryl carbon atom, together with a gold(I) atom that is linearly coordinated by the phosphorus atom of the arylphosphine and by iodide. The intramolecular gold-gold distance of 3.2201(3) Angstrom indica tes little or no interaction between the metal atoms. In contrast to the be havior of the homobridged complexes 1a and 1b, the heterobridged dithiocarb amate complexes 5a and 5b give structurally similar products on reaction wi th halogens, irrespective of the position of the ring methyl substituent. C rystal data for [Au-2(mu -C6H3-2-PPh2-5-Me)(mu -(S2CNBu2)-Bu-n)] (5a): tric linic, space group P (1) over bar (No. 2), with a = 11.3398(1), b = 15.9750 (2), c = 16.4400(3) Angstrom, alpha = 91.0735(9), beta = 109.3130(7), gamma = 90.7666(8)degrees, V = 2809.47(6) Angstrom (3), and Z = 4. Crystal data for [IAuI(mu -2-Ph2PC6H3-5-Me)(AuI)-I-III(eta (2)-(S2CNBu2)-Bu-n)] (8a): tr iclinic, space group P (1) over bar (No. 2), with a = 8.6136(2), b = 9.3273 , c = 21.1518(4) Angstrom, alpha = 84.008(1), beta = 84.945(1), gamma = 75. 181(1)degrees, V = 1630.54(6) Angstrom (3), and Z = 2.