title: Anchored [RuCl2(p-cymene)]2 in hybrid zirconium phosphate-phosphonate coated and pillared with double-stranded hydrophobic linear polystyrene as heterogeneous catalyst suitable for aqueous asymmetric transfer hydrogenation.
abstract: A novel type of phosphonate-containing polystyrene copolymers 1a-e bearing an N'-alkylated TsDPEN chiral ligand and double-stranded polystyrene chains were prepared for the first time using simple radical copolymerization of 1-phosphonate styrene with (R,R)-N'-4'-vinylbenzyl-N-4-vinylbenzenesulfonyl-1,2-diphenylethylene-1,2-diamine. Through the coprecipitation of their supported Ru polystyrene copolymers 2a-e and NaH2PO4 with ZrOCl2, pillared hybrid zirconium phosphate-phosphonate-anchored Ru catalysts 3a-e and 4d1-d5 were obtained as heterogeneous catalysts suitable for aqueous asymmetric transfer hydrogenation. In the aqueous asymmetric transfer hydrogenation of aromatic ketones, the anchored Ru catalysts showed good catalytic activities, chemoselectivities (~100%), and enantioselectivities (73.6% ee to 95.6% ee). The Ru catalysts retained their catalytic properties even at the fifth recycle time (92.2% conv., 92.1% ee). However, corresponding supported Ru catalyst 3d' resulted in disappointing reusability because of the loss of ruthenium in every recycle process. The conversions of aromatic ketones were closely related to the o-, m- or p-positions of the substituents on the aromatic ring caused by shape-selective matching.
authors.affiliation: College of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, P R China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.forename: Jingwei
authors.initials: J
authors.lastname: Wan
authors.forename: Xuebing
authors.initials: X
authors.lastname: Ma
authors.forename: Xiao
authors.initials: X
authors.lastname: Xu
authors.forename: Liu
authors.initials: L
authors.lastname: Liu
mesh_terms: D002384:Catalysis; D006865:Hydrogenation; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D063065:Organophosphonates / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism; D013499:Surface Properties; D014867:Water / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D063065:Organophosphonates; D011137:Polystyrenes; D014867:Water; C027006:zirconium phosphate; D012428:Ruthenium; D015040:Zirconium