SOLID-STATE NMR CHARACTERIZATION OF POLYSILOXANE MATRICES FUNCTIONALIZED WITH ETHER-PHOSPHINES AND THEIR RUTHENIUM(II) AND PALLADIUM(II) COMPLEXES

The monomeric ether-phosphine ligand (MeO)(3)Si(CH2)(3)(Ph)PCH(2)CH(2)OMe [1(T-0)] and its P-coordinated trimethoxysilyl-(T)-functionalized ruthenium and palladium complexes HRuCl (CO)(P similar to O)(3) [2(T-0)(3)] and Cl2Pd(P similar to O)(2) [3(T-0)(2)] were sol-gel processed with variable amounts of MeSi(OMe)(3) (T-0) and Me(2)Si(OEt)(2) (D-0) to give the polysiloxane-bound ether-phosphine ligands [1(T-n)(D-i)(y)], [1(T-n)(T-m)(2)], the ruthenium complexes [2(T-n)(3)(D-i)(y)], [2(T-n)(3)(T-m)(y)], and [2(T-n)(3)(T-PMS(m))y], and the palladium complexes [3(T-n)(2)(D-i)(y)] (Table 1) (P similar to O: eta(1)-P-coordinated ether-phosphine ligand; (T-n,T-m)(y), (D-i)(y): y = number of co-condensated T type (three oxygen neighbors), D type (two oxygen neighbors) silicon atom; n, m, i = number of Si-O-Si bonds; n, m = 0-3; i = 0-2; PMS = polymethylsiloxane; 1(T-n)(D-i)(y): [F-SiOn/2(OX)(3-n)] [Me(2)SiO(i/2)(OX)(2-i)](y), X = H, Me, Et; F = (Ph)P(CH(2)CH(2)OMe)(CH2)(3)- (1), 1(T-n)(T-m)(2): [F-SiOn/2(OX)(3-n)][MeSiO(m/s)(OX)(3-m)](2); 2(T-n)3(D-i)(y): [F-SiOn/2(OX)(3-n)](3)[Me(2)SiO(i/2)(OX)(2-i)](y), F = [HRuCl(CO)](1/3)(Ph)P(CH(2)CH(2)OMe)(CH2)(3)- (2); 3(T-n)(2)(D-i)(y): [F-SiOn/2(OX)(3-n)](2)[Me(2)SiO(i/2)(OX)(2-i)](y), F = (Cl2Pd)(1/2)(Ph)P(CH(2)CH(2)OMe)(CH2)(3)- (3); 2(T-n)(3)(T-m)(y), 2(T-n)(3)<T-PMS(m))(y): [F-SiOn/2(OX)(3-n)](3)[MeSiO(m/2)(OX)(3-m)](2)}. Si-29 CP MAS NMR spectroscopic investigations showed that there is an upper limit for the molar amount of y of the D-i units in the compounds 1(T-n)(D-i)(y), 2(T-n)(3)(D-i)(y), and 3(T-n)(2)(D-i)(y). The degree of condensation of the silicon units in 2(T-n)(3)(T-m)(y) depends on the amount of y of the T-m co-condensate. The line widths of the signals in the P-31 CP MAS NMR spectra suggest that the phosphorus atom of 1(T-n)(D-i)(y) has a very high mobility in comparison to the ligands 1(T-n)(T-m)(2) and [F-SiOn/2(OX)(3-n)][SiOk/2(OX)(4-k)](2) [1(T-n)(Q(k))(2)] [F = 1, Q(k): and type (four oxygen neighbors) silicon atom; k = 0-4, number of Si-O-Si bonds], and to the ruthenium complexes 2(T-n)(3)(T-m)(y). This was confirmed by the relaxation times in the rotating frame T-1 rho H and the cross polarization parameters T-XH (X = Si, P) It is concluded from T-SiH and T-1 rho H (via Si-29) data that the polysiloxane matrix becomes more flexible if D-0 units are used as the co-condensate. The polymeric materials 2(T-n)(3)(T-m)(y) are built up homogeneously for y = 0-48 on a scale of 3 nm, The T-1 rho H relaxation time was found to depend on the amount of y of the co-condensate. In the cases of y = 96 and of 2(T-n)(3)(T-PMS(m))(y) an interruption of the spin diffusion process was found, which indicates the formation of sever al aggregates. The spin diffusion rate was used to estimate a characteristic spin diffusion distance of 1.8 to 3 nm for y = 0-48, employing a model diffusion equation.