A new, higher yielding synthetic route towards dodecaphenyl cage silsesquioxanes: synthesis and mechanistic insights

Abstract

Cage dodecaphenylsilsesquioxane (T12-Phenyl) was synthesized in a one batch, mildly basic aqueous solution under room temperature conditions using a trialkoxysilane precursor. Significant improvements in synthetic yield (>95%) were observed compared with previous reports. Kinetic studies of the hydrolysis of phenyltrimethoxysilane were conducted and the condensation was monitored by (29)Si NMR which revealed the presence of a transient, intermediary T1 species as the pathway to dodecaphenylsilsesquioxane spherulites, and the tendency for T12 structures over T8, T10, and other substructures was explained through MM2 simulations.

A Study of the Influence of the HCl Concentration on the Composition and Structure of (Hydroxy)Arylsiloxanes from the Hydrolysis–Condensation Reaction of Aryltrichlorosilanes

“…The method was used in the study of alterations in the composition of primary intermediates in the hydrolysis–condensation reaction of phenyltrichlorosilane leading to (tetrahydroxy)(tetraphenyl)cyclotetrasiloxane, [PhSi(HO)O] 4 [16]. The 29 Si NMR spectroscopy method demonstrated that the reaction of hydrolysis–condensation of phenyltrimethoxysilane in the presence of a basic catalyst in different conditions occurred through an intermediate, tetrahydroxy(diphenyl)disiloxane [17]. When the reaction mixture was diluted, dodecaphenyldodecasilsesquioxane (phenyl-T 12 ) was obtained in 95% yield, while an increase in the concentration of the starting compound led to PPhSSO [17,18].…”

“…The 29 Si NMR spectroscopy method demonstrated that the reaction of hydrolysis–condensation of phenyltrimethoxysilane in the presence of a basic catalyst in different conditions occurred through an intermediate, tetrahydroxy(diphenyl)disiloxane [17]. When the reaction mixture was diluted, dodecaphenyldodecasilsesquioxane (phenyl-T 12 ) was obtained in 95% yield, while an increase in the concentration of the starting compound led to PPhSSO [17,18]. Hydrolysis of HSi(OMe) 3 in an acidic medium gave rise to tetramethoxydisiloxane as an intermediate compound, the thermal polycondensation of which afforded ladder organosilsesquioxane [19].…”

Mechanistic Insights into the Synthesis of Fully Condensed Polyhedral Octaphenylsilsesquioxane

“…According to the strategies of Albert, the existence of a T 1 species has been proved as the principal intermediate products in the synthesis of T 12 ‐phenyl compound . Studies of Kim and David on the synthesis of T 8 ‐phenyl compound have confirmed that the reaction pathway for T 8 ‐phenyl compound may occur through the condensation of the two tetraol T 2 species (Scheme ) .…”

Tunable Crystalline Phases in UV-Curable PEG-Grafted Ladder-Structured Silsesquioxane/Polyimide Composites

“…In order to improve upon the compatibility issues with inorganic materials, inorganic-organic hybrid materials such as silsesquioxanes have been touted as appropriate material due to both organic functional group and inorganic siloxane networks providing a bridge between both phases enabling high compatibility between organic polymer networks. While cage structured polyhedral oligomeric silsesquioxanes, commonly known as polyhedral oligomeric silsesquioxane (POSS) [18][19][20], have been widely reported as polyimide hybridization material [21], their low molecular weight, as well as relatively low solubility in organic solvents have limited their effectiveness as filler in many cases [22].…”