Details

Autor(en) / Beteiligte

• Lindner, Ekkehard
• Schneller, Theodor
• Mayer, Hermann A
• Bertagnolli, Helmut
• Ertel, Teja S
• Hörner, Wolfgang

Titel

Hydrocarbon-Bridged Methyldimethoxysilanes as new Co-condensation Agents for the Sol−Gel Process of the Rhodium(I) Complex ClRh(CO)(P∼O)2 Containing the Ligand PhP(CH2CH2OCH3)(CH2)3Si(OCH3)3 1|Pv3

Ist Teil von

• Chemistry of materials, 1997-07, Vol.9 (7), p.1524-1537

Ort / Verlag

American Chemical Society

Erscheinungsjahr

1997

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• New hydrocarbon bridged co-condensation agents of the type MeSi(OMe)2(CH2) z (MeO)2SiMe [1(D 0 − C z − D 0 ), z = length of the flexible bridging group (z = 6, 8, 14)] were synthesized and polycondensed to give the polysiloxanes 1(D i − C z − D i ). These monomers were employed in variable amounts y in the sol−gel processing of the monomeric ether−phosphine ligand PhP(CH2CH2OMe)(CH2)3Si(OMe)3 [2(T 0 )] and its P-coordinated trimethoxysilyl-(T)-functionalized rhodium(I) complex ClRh(CO)(P∼O)2 [3(T 0 ) 2 ] to yield the polysiloxane-bound ether−phosphine ligands 2(T n )(D i − C z − D i ) and the rhodium complexes 3(T n ) 2 (D i − C z − D i ) y [O∼P:  η1-P-coordinated ether−phosphine ligand; y = number of co-condensed D−C z −D molecules; D = D-type silicon atom (two oxygen neighbors), T = T-type silicon atom (three oxygen neighbors); i, n = number of Si−O−Si bonds; i = 0−2; n = 0−3]. The relative amounts of T and D silyl species and the degree of condensation were determined by 29Si CP/MAS NMR spectroscopic investigations. The polysiloxanes 1(D i − C z − D i ) which are regarded as “organofunctionalized Q analogues” display a higher degree of condensation than their Q counterpart [Q = Q-type silicon atom (four oxygen neighbors)]. The highest degrees of condensation of the D groups were obtained for the D−C14−D polymer and the F−T/D−C14−D copolymers [F = (Ph)P(CH2CH2OMe)(CH2)3− (2), [ClRh(CO)]1/2(Ph)P(CH2CH2OMe)(CH2)3− (3)]. 31P and 13C CP/MAS NMR spectroscopic studies give evidence that the ligand and the geometry of the complex is preserved during the entire sol−gel process. In addition an EXAFS spectroscopic analysis of the complex 3(T n ) 2 gave a more detailed description of its structure. 31P CP/MAS NMR relaxation time studies (T 1P, T PH, T 1 ρ H), 2D WISE NMR experiments, and the line widths of the 31P CP/MAS NMR spectra were applied for dynamic investigations. The noncomplexed ether−phosphine ligand in the F−T/D−C z −D copolymers is more mobile than that in the F−T/Q copolymer 2(T n )(Q k ) 2 [k = number of Si−O−Si bonds; k = 0−4]. The P-coordination of only two ether−phosphines in the complex leads to an additional cross-linking in the matrixes. Thereby the ligands become more rigid due to strong phosphorus−rhodium bonds.