ChemInform Abstract: Heterogeneous Enantioselective Epoxidation of Olefins Catalyzed by Unsymmetrical (Salen)Mn(III) Complexes Supported on Amorphous or MCM‐41 Silica Through a New Triazine‐Based Linker.

Abstract

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Porphyrin conjugated SiC/SiOx nanowires for X-ray-excited photodynamic therapy

“…On the basis of the experience of some of the authors on the functionalization of amorphous and mesoporous silica with various organic compounds1516, the NWs as grown on the Si substrates were first activated with aq. HCl and then reacted with 3-azidopropyltrimethoxysilane by refluxing in toluene.…”

Chiral Mn(III) salen complex immobilized on imidazole-modified mesoporous material via co-condensation method as an effective catalyst for olefin epoxidation

“…[14,15,27,28]. In most cases, relatively long reaction time was required over heterogeneous catalyst, owing to diffusional constraints [13][14][15][16][17]27,28] . As mentioned previously [24] , the ionic property of active centers may facilitate entry of reactants and oxidants into the channels of the catalysts and contact with the active sites, thus leading to shortened reaction time and increased catalytic activity.…”

“…However, the catalysts generally present problems in separation and recycling under homogeneous catalytic system. Consequently, the heterogenization of chiral Mn(Ⅲ) salen complexes has received great attention in the last decade [5][6][7][8][9][10][11][12][13][14][15][16][17] due to efficient product purification and easy catalyst recovery. However, in most cases, the heterogeneous chiral Mn(Ⅲ) salen catalysts would show lower activity and/or enantioselectivity than their homogeneous counterparts.…”

Asymmetric Hydrogenation and Transfer Hydrogenation of Ketones

“…Immobilization via covalent bonds is undoubtedly the most convenient, but on the other hand, it is the most challenging method for immobilization to perform on such supports (Jones et al, 2005;Steiner et al, 2004;Pugin et al, 2002;Sandree et al, 2001). For example, micelle templated silicas (MTS) featuring a unique porous distribution and high thermal and mechanical stabilities can be easily functionalized by the direct grafting of the functional organo-silane groups on their surfaces (McMorn & Hutchings, 2004;Heckel & Seebach, 2002;Bigi et al, 2002, Clark & Macquarrie, 1998Tada & Iwasawa, 2006). On the other hand, polar solvents such as water or alcohols and high temperatures during the catalytic procedure can promote the hydrolysis of the grafted moieties.…”