Stoichiometric and Catalytic Reactions of the Polysiloxane-Bound (Ether-Phosphine)Rhodium(I) Complex [ClRh(PO)(P ∼ O)] in Interphases
摘要:
AbstractThe reaction of four equivalents of the monomeric trimethoxysilyl(T)‐functionalized ether‐phosphine ligand CyP(CH2CH2OCH3)(CH2)3SiR3 (R = OMe [1 a(T0)], Me [1 b]) with [{μ‐ClRh(COE)2}2] yielded the monomeric pseudo 14 electron rhodium(I) complexes [ClRh(PO)(P∼O)] (2a(T0)2, 2 b). For the sol‐gel process the complex 2 a(T0)2 was protected by introduction of the volatile, reversibly binding ligand pyridine. Thus, the monomeric compound 2 a(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(Tn)2(Di‐C6‐Di)y (y = 2 and 8, respectively; i = 0–2; n = 0–3). The polysiloxane‐bound complex 2(Tn)2‐(Di‐C6‐Di)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(Tn)2‐(Di‐C6‐Di)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(Tn)2‐(Di‐C6‐Di)2 oxidatively added hydrogen to give the octahedrally configurated complex [ClRhH2(Py)(P ∼ O)2] [6(Tn)2(Di‐C6‐Di)2]. Treatment of dry 2(Tn)2‐(Di‐C6‐Di)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(Tn)2(Di‐C6‐Di)y (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(Tn)2(Di‐C6‐Di)y are more active than their monomeric congener 2 a(T0)2.
Stoichiometric and Catalytic Reactions of the Polysiloxane-Bound (Ether-Phosphine)Rhodium(I) Complex [ClRh(PO)(P ∼ O)] in Interphases
摘要:
AbstractThe reaction of four equivalents of the monomeric trimethoxysilyl(T)‐functionalized ether‐phosphine ligand CyP(CH2CH2OCH3)(CH2)3SiR3 (R = OMe [1 a(T0)], Me [1 b]) with [{μ‐ClRh(COE)2}2] yielded the monomeric pseudo 14 electron rhodium(I) complexes [ClRh(PO)(P∼O)] (2a(T0)2, 2 b). For the sol‐gel process the complex 2 a(T0)2 was protected by introduction of the volatile, reversibly binding ligand pyridine. Thus, the monomeric compound 2 a(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(Tn)2(Di‐C6‐Di)y (y = 2 and 8, respectively; i = 0–2; n = 0–3). The polysiloxane‐bound complex 2(Tn)2‐(Di‐C6‐Di)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(Tn)2‐(Di‐C6‐Di)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(Tn)2‐(Di‐C6‐Di)2 oxidatively added hydrogen to give the octahedrally configurated complex [ClRhH2(Py)(P ∼ O)2] [6(Tn)2(Di‐C6‐Di)2]. Treatment of dry 2(Tn)2‐(Di‐C6‐Di)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(Tn)2(Di‐C6‐Di)y (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(Tn)2(Di‐C6‐Di)y are more active than their monomeric congener 2 a(T0)2.