31199-56-1Relevant academic research and scientific papers
Palladium(I) Carbonyl Cation-Catalyzed Carbonylation of Olefins and Alcohols in Concentrated Sulfuric Acid
Xu, Qiang,Souma, Yoshie,Umezawa, Junya,Tanaka, Mutsuo,Nakatani, Hisako
, p. 6306 - 6311 (2007/10/03)
A new palladium catalyst was found to exhibit high catalytic activity for carbonylation of olefins and alcohols. cyclo-Bis(μ-carbonyl)dipalladium(I) cation (1) with bridging CO ligands is formed by reductive carbonylation of palladium sulfate, PdSO4, in concentrated H2SO4. When an olefin or alcohol is added, complex 1 changes to a new complex (2) with terminal CO ligands, and tertiary carboxylic acids are obtained in high yields at room temperature and atmospheric pressure of CO. IR and 13C NMR studies suggest that complex 2 may be tentatively formulated to be [Pd2(CO)2]2+, in which the terminal CO ligands are chemically equivalent. Complex 1 is a catalyst precursor, and complex 2 functions as an active species for the carbonylation of olefins and alcohols. The catalytic behavior of the palladium carbonyl catalyst supports the recently proposed reaction mechanism involving an olefin-metal-CO complex as an intermediate for the catalytic carbonylation of olefins and alcohols in strongly acidic solution.
A New Gold Catalyst: Formation of Gold(I) Carbonyl, [Au(CO)n]+ (n = 1, 2), in Sulfuric Acid and Its Application to Carbonylation of Olefins
Xu, Qiang,Imamura, Yuki,Fujiwara, Masahiro,Souma, Yoshie
, p. 1594 - 1598 (2007/10/03)
A new gold catalyst, [Au(CO)n]+ (n = 1, 2), was synthesized by using a facile method from commercial gold(III) oxide, Au2O3, in concentrated H2SO4, which exhibits high catalytic activity for carbonylation of olefins. The gold monocarbonyl [Au(CO)]+ (1) and dicarbonyl [Au(CO)2]+ (2) cations coexist in H2SO4 solution, the former of which is much more stable than the latter. Both of the carbonyls show IR spectra of vCO (2194, 2208 cm-1) higher than that of free CO (2143 cm-1), indicating nonclassical (σ-only) gold-CO bonding. The gold carbonyl complexes coexisting in the concd H2SO4 solution exhibit a single resonance in the 13C NMR spectrum at 171 ppm at ambient temperature and pressure, reflecting rapid CO exchange between 1 (164 ppm) and 2 (175 ppm). The nonclassical gold(I) carbonyl solution worked as an excellent catalyst, with which olefins reacted with CO to give tert-carboxylic acids in good yields at room temperature and atmospheric pressure. The gold(I) dicarbonyl cation 2 was found to function as an active species for the carbonylation. An olefin-gold(I)-carbonyl complex was proposed as a possible intermediate in the metal carbonyl-catalyzed carbonylation in the strongly acidic medium.
