Reactions of incompletely-condensed silsesquioxanes with pentamethylantimony: a new synthesis of metallasilsesquioxanes with important implications for the chemistry of silica surfaces

Composite materiomics

“…The last approach is commonly referred as a corner capping reaction which was first reported by Brown and Vogt [148] and further improved by Feher and Lichtenhan [93,151] and it is represented by a reaction of monomer with incompletely condensed (T 7 ) molecules; however, long reaction times and diversity limitations are the major disadvantages of this technique. Cohydrolysis of monomers with different organic moieties (R and R') leads to a mixture of products with all possible R/R' ratios, therefore further separation is necessary in order to receive pure substances.…”

Silica‐Supported Zirconium Complexes and their Polyoligosilsesquioxane Analogues in the Transesterification of Acrylates: Part 1. Synthesis and Characterization

“…These compounds have proven to be more realistic homogeneous models for silica surface silanols and in the past decade many hetero-and metallasilsesquioxanes as soluble analogues of heterogeneous silica-supported transition metal catalysts have been developed to gain further insights in the understanding of surface reactions and structural elucidation of surface complexes. [3,15] The trisilanol (R) 7 Si 7 O 9 (OH) 3 (R = cycloalkyl) is a suitable model for vicinal silanol sites of hydroxylated silica. The latter can be partially silylated with organochlorosilane [15] or fully condensed [16] with SiCl 4 fol- lowed by subsequent hydrolysis to provide isolated silanols present on deshydroxylated silica.…”

“…[3,15] The trisilanol (R) 7 Si 7 O 9 (OH) 3 (R = cycloalkyl) is a suitable model for vicinal silanol sites of hydroxylated silica. The latter can be partially silylated with organochlorosilane [15] or fully condensed [16] with SiCl 4 fol- lowed by subsequent hydrolysis to provide isolated silanols present on deshydroxylated silica. In our case, to produce analogues of the tripodal surface complexes, one simply reacted the cyclopentyl-derived trisilanol [c-C 5 H 9 ) 7 Si 7 O 9 (OH) 3 ] (A), which contains three adjacent silanol groups in close proximity with an appropriate zirconium precursor.…”

Recent Developments in the Chemistry of Molecular Titanosiloxanes and Titanophosphonates

“…Apparently the most thoroughly investigated class of complexes in this area are Ti complexes because of their promising catalytic applications (Feher et al, 1988). The first Ti derivatives were made by Feher et al (1988Feher et al ( , 1990 and include Ti(III) and Ti(IV) silsesquioxanes (1992 Corner-capping of the silsesquioxane framework with a TiCp unit can be readily achieved by reacting CpTiCl 3 with tetramethylstibonium derivative Cy 7 Si 7 O 9 (OSbMe 4 ) 3 or thallium derivative Cy 7 Si 7 O 9 (OTl) 3 , yielding monomeric Cy 7 Si 7 O 12 -TiCp (64) (Scheme 23) (Feher et al, 1992;Wada et al, 1998). The reaction of 61 with Ti(OiPr) 4 resulted in the formation of [Cy 7 Si 7 O 12 Ti(OiPr)] (66) (Maschmeyer et al, 1997).…”