Abstract: | The 13C n.m.r. spectra of forty alkoxysilanes of the general type XnSi(OR)4–n (X = CH3, C6H5, H; R = CH3, C2H5, n-C3H7, i-C3H7, n-C4H9, i-C4H9, s-C4H9, n-C5H11, CH(CH3)(C6H5), C6H5) have been recorded and assigned. The chemical shifts of the α-carbon resonances of the alkoxy groups are shown to depend on both the nature of the alkoxy group and the number and type of substituents on the silicon. Regression analyses of the data give empirical substituent chemical shift (SCS) parameters for the silyl substituents. The β-carbon resonances are shown to be dependent on the presence of the silyl group, but not the specific silyl substituents. |