Supported organometallic complexes. Part 27: novel sol-gel processed rhodium(I) complexes: synthesis, characterization, and catalytic reactions in interphases

摘要

A novel T-silyl functionalized cationic (COD)(dppp)rhodium(l) complex was sol-gel processed with various amounts of the co-condensing agents MeSi(OMe)(2)(CH2)(6)(OMe)(2)SiMe and MeSi(OMe)(2)(CH2)(3)(C6H4)(CH2)(3)(OMe)(2)SiMe to give novel stationary phases for 'Chemistry in Interphases'. The polysiloxane matrices and the integrity of the rhodium(I) complex centers were investigated by means of multinuclear solid-state NMR (C-13, Si-29, P-31) and EXAFS spectroscopics. Dynamic NMR measurements show an increasing mobility of the matrix and the reactive centers with a higher amount of the co-condensing component. The accessibility of the anchored rhodium(I) centers was scrutinized by the metal catalyzed hydrogenation of 1-hexene. All applied xerogels show remarkable activities and selectivities. An enhancement of the activities is achieved when polar solvents are used. SEM micrographs reveal the morphology of the hybrid materials and energy dispersive X-ray spectroscopy (EDX) suggests that the distribution of the elements is in satisfying agreement with the applied composition. (C) 2002 Published by Elsevier Science B.V. [References: 53]