Hydrocarbon-Bridged Methyldimethoxysilanes as new Co-condensation Agents for the Sol−Gel Process of the Rhodium(I) Complex ClRh(CO)(P∼O)₂Containing the Ligand PhP(CH₂CH₂OCH₃)(CH₂)₃Si(OCH₃)₃¹|Pv³

New hydrocarbon bridged co-condensation agents of the type MeSi(OMe) 2 (CH 2 ) z (MeO) 2 SiMe [ 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(CH 2 CH 2 OMe)(CH 2 ) 3 Si(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: η 1 -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 29 Si 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−C 14 −D polymer and the F−T/D−C 14 −D copolymers [F = (Ph)P(CH 2 CH 2 OMe)(CH 2 ) 3 − ( 2 ), [ClRh(CO)] 1/2 (Ph)P(CH 2 CH 2 OMe)(CH 2 ) 3 − ( 3 )]. 31 P and 13 C 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. 31 P CP/MAS NMR relaxation time studies ( T 1P, T PH, T 1 ρ H ), 2D WISE NMR experiments, and the line widths of the 31 P 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.