title: Understanding the leaching properties of heterogenized catalysts: a combined solid-state and PHIP NMR study.
abstract: Para-hydrogen induced polarization (PHIP) NMR in solution, combined with solid-state NMR, can be efficiently employed for the highly sensitive in-situ detection of the leaching properties of immobilized catalysts. The knowledge of this property is important for possible applications of PHIP experiments in medicine, biology or industry, where leached catalysts poison the solution of hyperpolarized products. As experimental example Wilkinson's catalyst RhCl(PPh(3))(3) (1) immobilized on mesoporous silica is chosen. As model reaction the hydrogenation of styrene in solvents with different polarities (methanol-d(4), acetone-d(6) and benzene-d(6)) is used. A (31)P solid-state MAS-NMR study reveals that there are two different species of catalysts on the silica, namely coordinatively bound catalysts and physisorbed catalyst. Only the second species exhibits substantial leaching, which is visible in a strong PHIP enhancement of the reaction product.
authors: Institute of Physical Chemistry, Technical University Darmstadt, Petersenstrasse 22, D-64287 Darmstadt, Germany.
authors: Torsten
authors: T
authors: Gutmann
authors: Tomasz
authors: T
authors: Ratajczyk
authors: Yeping
authors: Y
authors: Xu
authors: Hergen
authors: H
authors: Breitzke
authors: Anna
authors: A
authors: Grünberg
authors: Sonja
authors: S
authors: Dillenberger
authors: Ute
authors: U
authors: Bommerich
authors: Thomas
authors: T
authors: Trantzschel
authors: Johannes
authors: J
authors: Bernarding
authors: Gerd
authors: G
authors: Buntkowsky
mesh_terms: D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry*; D006865:Hydrogenation; D007221:Industry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: C509969:SBA-15; D012822:Silicon Dioxide; D006859:Hydrogen