Silanone

Abstract: Photochemical materials are of scientific and practical importance in the field of photocatalysis. In this study, the photochemistry of several organic contaminants, including decabromodiphenyl ether (BDE-209), halogenated phenols (C6 X5OH, X = F, Cl, Br) and paraffin, on silica gel (SG) surface was investigated under simulated solar irradiation conditions. Photolysis of these compounds at the solid/air interface proceeds with different rates yielding various hydroxylation products, and hydroxyl radical was determined as the major reactive species. According to density functional theory (DFT) calculations, the reaction of physically adsorbed water with reactive silanone sites (>Si═O) on silica was indispensable for the generation of •OH radical, where the required energy matches well with the irradiation energy of visible light. Then, the BDE-209 was selected as a representative compound to evaluate the photocatalytic performance of SG under different conditions. The SG material showed good stability in the photodegradation process, and was able to effectively eliminate BDE-209 under natural sunlight. These findings provide new insights into the potential application of SG as a solid surface photocatalyst for contaminants removal.

Abstract: SiO in a complex: The first silanone that is stable at room temperature (3) is reported. The two-step synthesis involves carbonylation of the silylidyne complex 1 to give the chromiosilylene 2, followed by oxidation of 2 with N2 O. Silanone 3 features a polar, short SiO bond (1.526(3) A) to a trigonal-planar-coordinated silicon center and reacts with water to give the dihydroxysilyl complex.

Abstract: Six alternative decomposition modes of silanol are examined with ab initio electronic structure theory. Geometries determined at the MP2/6-31G(d,p) level of computation and single-point energetics obtained with MP4/MC-311G(d,p) wave functions predict that the 1,1- and 1,2-eliminations of molecular hydrogen are both thermodynamically and kinetically competitive, with all other processes requiring at least 10 kcal/mol more energy to occur. At the highest level of theory, silanone is predicted to be 2.7 kcal/mol lower in energy than hydroxysilylene