17O, 13C, and 29Si NMR spectra of some acyloxy- and diacetoxysilanes and acetoxygermanes

The 17 O, 13 C, and 29 Si NMR spectra of (CH 3 ) 3 SiOC(O)R, CH 3 (XCH 2 )Si(OC(O)CH 3 ) 2 , and R 3 GeOC(O)CH 3 compounds are reported. In the 17 O NMR spectra at 350 K the only signal is observed with the two latter series, but two well-resolved signals are displayed with the (CH 3 ) 3 SiOC(O)R compounds. The equivalence of both oxygen atoms in carboxyl group on the NMR time scale is discussed from the viewpoint of a possible coordination of the oxygen atoms to the IVB group element of the periodic system.