Synthesis and Characterization of Sulfur-Ylide Complexes of Gold(I). Observance of Intermolecular Gold(I)−Gold(I) Interactions in Solution

• Published in: Organometallics 1997-03, Vol.16 (5), p.901-909
• Main Authors: Feng, Da-Fa, Tang, Shaw Shiah, Liu, C. W, Lin, Ivan J. B, Wen, Yuh-Sheng, Liu, Ling-Kang
• Format: Article
• Language: English
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om960748j

Under PTC/OH- (PTC = phase-transfer catalysis) conditions, the reaction of Au2(dppm)Cl2 (dppm = 1,1-bis(diphenylphosphino)methane) with [Me2S(O)NMe2]BF4 produces a greenish luminescent compound [Au2(dppm)[(CH2)2S(O)NMe2]]BF4, 1, and a colorless tetranuclear compound [Au4(dppm)(Ph2PCHPPh2)[(μ-CH)(CH2)S(O)NMe2]]BF4, 2. Both compounds 1 and 2 also can be synthesized from [Au4(dppm)(Ph2PCHPPh2)Cl3], 3, which can be produced simply by the reaction of Au2(dppm)Cl2 with OH- in the presence of a PTC. For Au2(dppe)Cl2 (dppe = 1,2-bis(diphenylphosphino)ethane) and Au2(dmpm)Cl2 (dmpm = 1,1-bis(dimethylphosphino)methane), only [Au2(dppe)[(CH2)2S(O)NMe2]]PF6, 4, and [Au2(dmpm)[(CH2)2S(O)NMe2]]BF4, 5, are obtained as the major product, respectively. Compounds 1−4 are characterized by single-crystal X-ray analyses. Two C 2-related cations of 1 are packed in a row with the intermolecular Au−Au distance (2.959 Å) shorter than the intramolecular Au−Au distance (2.984 Å). Compound 2 has one of the ylide carbon atoms bridging two gold(I) atoms. The tetragold cluster of 3 is formed by an Au−C linkage between [ClAu(μ-Ph2PCH2PPh2)Au]+ and [ClAu(μ-Ph2PCHPPh2)AuCl]-. The digold cation of 4 is a nine-membered dimetallocycle. In acetonitrile solution, dimerization of 1 and 5 through intermolecular Au−Au interaction occurs as evidenced by concentration-dependent absorption spectroscopic studies. Concentration-dependent absorption spectra of 1 and 5 suggest that equilibriums between the monomer and dimer exist with equilibrium constants of 33 ± 9 and 52 ± 7 M-1 in acetonitrile, respectively. Digold(I) compounds 1, 4, and 5 luminesce in the solid state.