201554-67-8Relevant academic research and scientific papers
Stoichiometric and catalytic reactions of the polysiloxane-bound (ether-phosphine)rhodium(I) complex [ClRh(PO)(P ~ O)] in interphases
Lindner, Ekkehard,Schneller, Theodor,Auer, Friedrich,Wegner, Peter,Mayer, Hermann A.
, p. 1833 - 1845 (1997)
The reaction of four equivalents of the monomeric trimethoxysilyl(T)-functionalized ether-phosphine ligand CyP(CH2CH2OCH3)(CH2)3SiR3 (R = OMe [1a(T0)], Me [1b]) with [{μ-C1Rh(COE)2}2] yielded the monomeric pseudo 14 electron rhodium(I) complexes [C1Rh(PO)(P ~ O)] (2a(T0)2, 2b). For the sol-gel process the complex 2a(T0)2 was protected by introduction of the volatile, reversibly binding ligand pyridine. Thus, the monomeric compound 2a(T0)2 was co-condensed with two and eight equivalents of the co-condensation agent MeSi(OMe)2(CH2)6(MeO)2SiMe (D0-C6-D0) to give the polysiloxane-bound congeners 2(T(n))2(D1-C6-D1)(y) (y = 2 and 8, respectively; i = 0-2; n = 0-3). The polysiloxane-bound complex 2(T(n))2 (D(i)-C6-D(i))2 was treated with a variety of small molecules in the gas/solid and liquid/solid interphases. It was shown that a facile cleavage of the Rh-O bond in the ether-phosphine chelate occurred even in the solid state. The reaction of 2(T(n))2-(D(i)C6-D(i))2 with carbon monoxide, carbon disulfide, and diphenylacetylene resulted in the irreversible coordination of the molecule to the metal. In the presence of pyridine, the polysiloxane-bound complex 2(T(n))2(D(i)-C6-D(i))2 oxidatively added hydrogen to give the octahedrally configurated complex [ClRhH2(Py)(P ~ O)2] [6(T(n))2(D(i)-C6-D(i))2]. Treatment of dry 2(T(n))2(D(i)-C6-D(i))2 with ethene led to the reversible formation of the corresponding complex. Although the materials display low surface areas, at least 75% of the rhodium centers within the matrix are accessible to the rather bulky tolan molecules. The complexes 2(T(n))2(D(i)-C6-D(i))(y) (y = 2, 8) show high activities and selectivities in the hydrogenation of tolan. The conversion was found to depend markedly on the amount of co-condensate D0-C6-D0 and on the polarity of the solvent. The polysiloxane-bound complexes 2(T(n))2(D(i)-C6D(i))(y) are more active than their monomeric congener 2a(T0)2.
