Sodium, calciu, aluminum, zinc and europium salts of p-phenyelen-bis(silanetriolate). Access to a new class of organosilicates

摘要

The crystalline sodium salt of p-phenylenebis(silanetriolate),(NaO)_3SiC_6H_4Si(ONa)_3; 14H_2O has been prepared in quantitative yield by reaction of the corresponding alkoxysilane with NaOH. Characterization of its structure indicates two different environments ofr the silicon atoms (X-ray and ~(13)C, ~(29)Si, ~H NMR) in the solid state. Drying of the salt by thermal treatment between 20 and 180degC (TG analysis) led to a modification of the structure without loss of the organic group. Elimination of C_6H_6 occurs above 200degC and formation of the sodium silicate Na_2SiO_3 can be identified above 400degC (X-ray diffraction). Quantitative replacement of the sodium cation with Al~(3+), Zn~(2+), Ca~(2+) and Eu~(3+) has been achieved resulting in the formation of the corresponding silanetriolates (EDX and elemental analyses). X-ray diffraction analysis suggests the presence of a lamellar structure on very small domains or a short range order.