Pyrolysis Behavior of Organic-Inorganic Hybrids with Si-O-Nb/Si-O-Ta Oxygen Bridged Heterometallic Bonds

Abstract

The pyrolysis behavior of organic-inorganic hybrids with Si-O-Nb/Si-O-Ta oxygen bridged heterometallic bonds was investigated. The easy cleavage of Si-O-Nb bonds was confirmed by infrared (IR) spectra, and Si-O-Ta bonds were broken at higher temperatures, suggesting the difference in energy between Si-O and O-M (M=Nb and Ta). The decomposition from T unit to D and Q units was analyzed by 29Si-nuclear magnetic resonance (NMR). The redistribution due to the exchange reactions between Si-O and Si-C bonds was confirmed, which was also supported by thermogravimetric analysis-mass spectroscopy (TG-MS) results. Disiloxane and silane from the hybrid with Si-O-Nb bonds were detected at lower temperatures than those from the hybrids with Si-O-Ta or without Si-O-Nb bonds. The evolution temperature of these gases was close to the cleavage temperature of Si-O-Nb/Si-O-Ta bonds, which indicates that the cleavage of Si-O-Nb/Si-O-Ta bonds affects the redistribution.