SYNTHESIS AND CHARACTERIZATION OF SULFUR-YLIDE COMPLEXES OF GOLD(I) -OBSERVANCE OF INTERMOLECULAR GOLD(I)-GOLD(I) INTERACTIONS IN SOLUTION

Under PTC/OH- (PTC phase-transfer catalysis) conditions, the reaction of Au-2(dppm)Cl-2 (dppm = 1,1-bis(diphenylphosphino)methane) with [Me( 2)S(O)NMe(2)]BF4 produces a greenish luminescent compound [Au-2(dppm>[ (CH2)(2)S(O)NMe(2)]]BF4, 1, and a colorless tetranuclear compound dppm )(Ph(2)PCHPPh(2))[(mu-CH)(CH2)S(O)NMe(2)]]BF4, 2. Both compounds 1 and 2 also can be synthesized from [Au-4(dppm)(Ph(2)PCHPPh(2))Cl-3], 3, w hich can be produced simply by the reaction of Au-2(dppm)Cl-2 with OH- in the presence of a PTC. For Au-2(dppe)Cl-2 (dppe = 1,2-bis(diphenyl phosphino)ethane) and Au-2(dmpm)Cl-2 (dmpm = 1,1-bis(dimethylphosphino )methane), only [Au-2(dppe)[(CH2)(2)S(O)NMe(2)]]PF6, 4, and [Au-2(dmpm )[(CH2)(2)S(O)NMe(2)]]BF4, 5, are obtained as the major product, respe ctively. Compounds 1-4 are characterized by single-crystal X-ray analy ses. Two Ct-related cations of 1 are packed in a row with the intermol ecular Au-Au distance (2.959 Angstrom) shorter than the intramolecular Au-Au distance (2.984 Angstrom). Compound 2 has one of the ylide carb on atoms bridging two gold(I) atoms. The tetragold cluster of 3 is for med by an Au-C linkage between [ClAu(mu-Ph(2)PCH(2)PPh(2))Au](+) and [ ClAu(mu-Ph(2)PCHPPh(2))AuCl](-). The digold cation of 4 is a nine-memb ered dimetallocycle. In acetonitrile solution, dimerization of 1 and 5 through intermolecular Au-Au interaction occurs as evidenced by conce ntration-dependent absorption spectroscopic studies. Concentration-dep endent absorption spectra of 1 and 5 suggest that equilibriums between the monomer and dimer exist with equilibrium constants of 33 +/- 9 an d 52 +/- 7 M(-1) in acetonitrile, respectively. Digold(I) compounds 1, 4, and 5 luminesce in the solid state.