Synthesis and characterization of some dimethylsilicon(IV) complexes with internally functionalized oximes: Crystal and molecular structure of [Me2Si{ONC(H)C4H3O-2}2]. Formation of mesoporous materials by the hydrolytic study of [Me2Si{ONC(CH3)C4H3O-2}2] in the presence of Al(OPri)3

Reactions of Me 2 SiCl 2 in a 1:2 molar ratio with internally functionalized oximes in the presence of Et 3 N in anhydrous benzene afford compounds of the type [Me 2 Si{ON C(R)Ar} 2 ] {where R = Me, Ar = 2-C 5 H 4 N ( 1 ), 2-C 4 H 3 O ( 2 ), 2-C 4 H 3 S ( 3 ); R = H, Ar = 2-C 5 H 4 N ( 4 ), 2-C 4 H 3 O ( 5 ), 2-C 4 H 3 S ( 6 )}. Molecular weight measurements of all these derivatives in freezing benzene and the FAB mass spectral studies of 1 and 6 indicate that these complexes are monomeric. The 1 H and 13 C{ 1 H} NMR spectra suggest that the oximate moieties are monofunctional monodentate in solution. 29 Si{ 1 H} NMR signals appear in the region expected for tetra-coordinated dimethyl silicon atoms. Single crystal X-ray diffraction analysis of [Me 2 Si{ON C(H)C 4 H 3 O-2} 2 ] ( 5 ) confirms the presence of a distorted tetrahedron as the immediate environment around silicon. Secondary weak β-donor bonding is also observed in the solid state, indicating that silicon is in the (4+2) coordination state. The TGA curve of [Me 2 Si{ON C(H)C 4 H 3 O-2} 2 ] shows the high thermal stability and volatile nature of the complex. A comparison of hydrolytic studies of a mixture of [Me 2 Si{ON C(CH 3 )C 4 H 3 O-2} 2 ] and Al(OPr i ) 3 in a 1:2 molar ratio with those of pure Al(OPr i ) 3 under similar conditions by the sol–gel technique suggests the formation of a silicon embedded amorphous powder 7 and γ-alumina 8 , respectively. The variation in specific surface area, total pore volume and pore size indicate formation of mesoporous materials.