New hydrocarbon bridged co-condensation agents of thetypeMeSi(OMe)
2(CH
2)
z(MeO)
2SiMe[
1(D0-Cz-D0),
z = length of the flexible bridging group (
z= 6, 8, 14)] were synthesizedand polycondensed to give the polysiloxanes
1(Di-Cz-Di).These monomers were employedin variable amounts
y in the sol-gel processing of themonomeric ether-phosphine ligandPhP(CH
2CH
2OMe)(CH
2)
3Si(OMe)
3[
2(T0)] and itsP-coordinated trimethoxysilyl-(T)-functionalized rhodium(I) complexClRh(CO)(P~O)
2[
3(T0)2]to yield the polysiloxane-boundether-phosphine ligands
2(Tn)(Di-Cz-Di)and the rhodium complexes
3(Tn)2(Di-Cz-Di)y[O~P:
1-P-coordinated ether-phosphine ligand;
y = number of co-condensedD-C
z-Dmolecules; D = D-type silicon atom (two oxygen neighbors), T =T-type silicon atom (threeoxygen neighbors);
i,
n = number of Si-O-Sibonds;
i = 0-2;
n = 0-3]. Therelative amountsof T and D silyl species and the degree of condensation were determinedby
29Si CP/MASNMR spectroscopic investigations. The polysiloxanes
1(Di-Cz-Di)which are regarded as"organofunctionalized Q analogues" display a higher degree ofcondensation than their Qcounterpart [Q = Q-type silicon atom (four oxygen neighbors)].The highest degrees ofcondensation of the D groups were obtained for theD-C
14-D polymer and the F-T/D-C
14-D copolymers [F =(Ph)P(CH
2CH
2OMe)(CH
2)
3-(
2),[ClRh(CO)]
1/2(Ph)P(CH
2CH
2OMe)(CH
2)
3- (
3)].
31Pand
13C CP/MAS NMR spectroscopic studies give evidence thatthe ligandand the geometry of the complex is preserved during the entiresol-gel process. In additionan EXAFS spectroscopic analysis of the complex
3(Tn)2gave a more detailed description ofits structure.
31P CP/MAS NMR relaxation time studies(
T1P,
TPH,
T1H), 2D WISENMRexperiments, and the line widths of the
31P CP/MAS NMRspectra were applied for dynamicinvestigations. The noncomplexed ether-phosphine ligand in theF-T/D-C
z-D copolymersis more mobile than that in the F-T/Q copolymer
2(Tn)(Qk)2[
k = number of Si-O-Si bonds;
k = 0-4]. The P-coordination of only twoether-phosphines in the complex leads to anadditional cross-linking in the matrixes. Thereby the ligandsbecome more rigid due to strongphosphorus-rhodium bonds.