Mobility Studies on Sol−Gel Processed Ether−Phosphines and Their Ruthenium(II) Complexes with Different Spacer Lengths. A Solid-State NMR Study1,2

The monomeric ether−phosphine ligands (MeO) 3 Si(CH 2 ) x (Ph)PCH 2 CH 2 OMe { x = number of methylene groups; x = 3 [ 1a(T 0 ) ], 6 [ 1b(T 0 ) ], 8 [ 1c(T 0 ) ]} and their P-coordinated trimethoxysilyl-(T)-functionalized ruthenium complexes cis -Cl(H)Ru(CO)(P∼O) 3 [ 2a(T 0 ) 3 ], [ 2b(T 0 ) 3 ], and [ 2c(T 0 ) 3 ] were sol−gel processed with fixed amounts of Si(OEt) 4 ( Q 0 ), MeSi(OMe) 3 ( T 0 ), and Me 2 Si(OEt) 2 ( D 0 ) to give the polysiloxane-bound ether−phosphine ligands [ 1(a,b,c)(T n )(Q k,T m,D i ) y ] and the ruthenium complexes [ 2(a,b,c)(T n ) 3 (Q k,T m,D i ) y ] [P∼O: η 1 -P-coordinated ether−phosphine ligand; y = number of co-condensed Q, T, or D type; Q = Q type silicon atom (four oxygen neighbors), T = T type silicon atom (three oxygen neighbors), D = D type silicon atom (two oxygen neighbors); i, k, n, m = number of Si−O−Si bonds; i = 0−2; n, m = 0−3; k = 0−4]. Solid-state 29 Si NMR spectroscopy has been used to show that the matrixes containing ligands or complexes have comparable structures, independently from the employed spacer ( n -propyl, n -hexyl, or n -octyl). Detailed 31 P NMR relaxation time studies ( T 1P, T PH, T 1ρH ), 2D WISE NMR spectroscopy, and the line widths of the 31 P CP/MAS NMR spectra have been applied for dynamic investigations. The noncomplexed ether−phosphine ligands are highly mobile and their flexibility is enhanced by longer spacers for all types of matrixes. The mobility of the ligands is also dependent upon the employed co-condensate. Functionalized F-T/Q copolymers are less flexible than F-T/T or even F-T/D copolymers [F = −(CH 2 ) x P(Ph)CH 2 CH 2 OMe]. The P-coordination of the ether−phosphines in the complexes led to an additional cross-linking in the matrixes. Thereby the ligands become more rigid due to strong phosphorus−ruthenium bonds. The differences of the mobilities of the different polymer-bound complexes are smaller compared to the noncomplexed ligands.