Aqueous Room‐Temperature Gold‐Catalyzed Chemoselective Transfer Hydrogenation of Aldehydes

Abstract

By the use of atomic force microscopy (AFM), formation mechanism of nodular structure in cellulose acetate membranes was systematically investigated. Elementary factors affecting the nodule formation were delineated on the basis of both kinetic and thermodynamic considerations. It was shown that (1) the exact nature of nodular structure is thermodynamic equilibrium glassy state; nodular structure will vanish in the rubbery state; (2) the thermodynamic factor affecting nodule formation is the membrane formation temperature; with the membrane formation temperature decreasing, more chain segments are able to form nodular structures; (3) nodule formation is dependent on the segment rearrangement; variation of the solvent environment is the major kinetic factor affecting the segment rearrangement and nodule formation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1328–1335, 2003

[Ag25(SR)18]−: The “Golden” Silver Nanoparticle

“…Experimental data matched well with the simulation (see inset) for the molecular formula [Ag 25 (SPhMe 2 ) 18 ] , indicating that the entire cluster possesses a unit negative charge. Further analysis of our purified product in the positive ionization mode found the PPh 4 + cation ( Figure S4), confirming that the cluster core is indeed negatively charged; thus, establishing the purified product's identity as [Ag 25 (SPhMe 2 ) 18 ] PPh 4 + . In order to investigate the crystal structure of the synthesized cluster with single-crystal X-ray diffraction, we crystallized the clusters from a DCM/hexane mixture at 4 °C over 2-7 days.…”

Understanding the synergistic effects of gold bimetallic catalysts

“…Supported gold nanocatalysts have shown great potentials in the selective hydrogenation of aldehydes [97], olefins [5,98], and nitroaromatics [99]. In comparison with PGM catalysts, gold is particularly sensitive in discriminating different functional groups in polysubstituted compounds, and thereby offers unique chemoselectivity.…”

Photocatalytic hydrogenation of organic compounds in membrane reactors

“…Moreover, the reduction of benzophenone to benzhydrol (hydroxydiphenyl methane; (C 6 H 5 ) 2 CHOH) has received much attention because its derivatives are important intermediates in the pharmaceutical industry (Meltzer et al, 1996). The reduction of ¼C¼O and multiple bonds using hydrogen gas flow and metal catalysts is widely reported (Alonso et al, 2008;Baruwati, Polshettiwar, & Varma, 2009;Gladiali & Alberico, 2006;He et al, 2009;Ikariya & Blacker, 2007;Malacea, Poli, & Manoury, 2010;Yu, Wu, Ramarao, Spencer, & Ley, 2003;Zhao, Yu, Yan, & Li, 2009). Other applications of benzhydrol are in the synthesis of agrochemicals (e.g., hexachlorophene and dichlorophen), as a fixative in the perfumery industry, and as a terminating group in polymerization reactions (Escobar et al, 2010).…”