title: Supported Tetrahedral Oxo-Sn Catalyst: Single Site, Two Modes of Catalysis.
abstract: Mild calcination in ozone of a (POSS)-Sn-(POSS) complex grafted on silica generated a heterogenized catalyst that mostly retained the tetrahedral coordination of its homogeneous precursor, as evidenced by spectroscopic characterizations using EXAFS, NMR, UV-vis, and DRIFT. The Sn centers are accessible and uniform and can be quantified by stoichiometric pyridine poisoning. This Sn-catalyst is active in hydride transfer reactions as a typical solid Lewis acid. However, the Sn centers can also create Brønsted acidity with alcohol by binding the alcohol strongly as alkoxide and transferring the hydroxyl H to the neighboring Sn-O-Si bond. The resulting acidic silanol is active in epoxide ring opening and acetalization reactions.
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Beletskiy
authors.affiliation: Northwestern Polytechnical University , Xi'an, Shaanxi 710072, PR China.
authors.forename: Xianliang
authors.initials: X
authors.lastname: Hou
authors.forename: Zhongliang
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Chemical Sciences Division, Argonne National Laboratory , Naperville, Illinois 60429, United States.
authors.forename: James R
authors.initials: JR
authors.lastname: Gallagher
authors.affiliation: Chemical Engineering Department, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Miller
authors.forename: Yuyang
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Northwestern Polytechnical University , Xi'an, Shaanxi 710072, PR China.
authors.forename: Tiehu
authors.initials: T
authors.lastname: Li
authors.forename: Mayfair C
authors.initials: MC
authors.lastname: Kung
authors.forename: Harold H
authors.initials: HH
authors.lastname: Kung