Structure of organic–inorganic hybrid low-melting glasses from 29Si NMR and ab initio molecular orbital calculations

Abstract The structure of organic–inorganic hybrid glass precursor Me2Si(OPO(OH)2)2 and low-melting glasses SnO–Me2SiO–P2O5 has been examined by 29Si static and MAS NMR, respectively. The 29Si MAS NMR spectra of SnO–Me2SiO–P2O5 were deconvoluted into three Gaussian peaks, whose chemical shifts were located at −3.1, −10.2 and −18.1 ppm. Ab initio molecular orbital calculations have also been carried out for the clusters modeling the structure of precursor and glasses. From the calculations of 29Si NMR shielding constants, the experimental chemical shifts at −10.2, −3.1 and −18.1 ppm were assigned to 29Si atoms in P–O–Si(Me)2–O–P network linkage, in P–O–Si(Me)2–OH terminating structure and in P–O–Si(Me)2–O–Si network linkage, respectively. Based on the area ratio of the assigned three peaks, the network structures around Si constructing SnO–Me2SiO–P2O5 low-melting glasses were discussed in detail.