I N T R O D U C T I O NRecently, various complexes containing cyclohexylphenylphosphine ligands have been shown to be powerful catalysts.' Their catalytic properties and activity, however, change dramatically when they function as supported liquid-phase catalysts. In order to understand better these changes, we have undertaken a iimited study of the NMR spectra of iigands having the general formula P(C,H, 1),,(C6H5)3 -,, and the results are reported in this paper. The I3C chemical shifts in the spectra of triphenylphosphine (1) cyclohexyldiphenylphosphine (2) and tricyclohexylphosphine (4) were assigned straightforwardly according to the line intensity and multiplicity, known substituent effects and relative magnitudes of the ' 3C-31 P spin-spin coupling constants.* Similarly assigned were the aromatic carbons and the doublet of the cyclohexyl methine carbon in the spectrum of dicyclohexylphenylphosphine (3). The assignment of the remaining lines required INADEQUATE experiments and the use of a higher magnetic field, as the chemical

No abstract

A series of Rh, Pd, and Pt complexes was prepared whose tert-phosphine, tert-amine, cyano or pyridine ligands are bonded directly or through alkylene chain to inorganic supports. The complexes were tested as catalysts for hydrosilylation of several alkene~ and of 1,3-butadiene by trichloro-, triethyl-, and triethoxysilane. In comparison with similar soluble complexes, supported catalysts were more selective and some could be reused. In several cases their effectivness was greater than that of the soluble catalysts. The factors influencing the activity of supported catalysts are discussed.

No abstract

No abstract