Synthesis and Polymerization of a para-Disubstituted T8-caged Hexaisobutyl-POSS Monomer

Abstract

A para-substituted bis(3-aminopropyl)hexaisobutyl-polyhedral oligomeric silsesquioxane (POSS) was successfully synthesized via a selective corner-opening reaction of 3-aminopropylheptaisobutyl-POSS and a subsequent corner-capping reaction. The selectivity of the corner-opening reaction was studied by density functional theory calculations. Polymerization of the POSS monomer with pyromellitic dianhydride resulted in a yellow, self-standing film.

Stochastic/Controlled Symmetry Breaking of the T8‐POSS Cages toward Multifunctional Regioisomeric Nanobuilding Blocks

“…There are three diadducts with distinct symmetry, commonly referred to as ortho ‐, meta ‐, and para ‐diadducts, based on a cubic framework (Figure 1). 16, 20a, 25a The clean MALDI‐TOF mass spectra (Figure S1 in the Supporting Information) confirm the intact POSS cage after functionalization and suggest that F1, F2, and F3 are the three regioisomers. A combination of 1 H, 13 C, and 29 Si NMR spectrometry were used to assign the configurations.…”

para-Bisvinylhexaisobutyl-substituted T8 caged monomer: synthesis and hydrosilylation polymerization

“…After the solvent was removed under reduced pressure and dried in vacuo, partially condensed trisilanol vinylhexaisobutyl-substituted T 8 cage was obtained as a colorless solid in 89% yield. When the same corner-opening proceeded at 80 ˚C for 7 h, that is optimal condition for preparing the partially condensed trisilanol 3-aminopropyl hexaisobutyl-substituted T 8 cage previously reported, 8 a lot of signals beside expected peaks were observed in 29 Si NMR of the product, suggesting excessive hydrolysis proceeded in this condition.…”

“…9 The LUMO+1 pattern shown in Figure 2 predicts a confinement of the lobe in the center of the T 8 cage; a similar result was found in a modelling study on the unsubstituted T 8 cage, [HSiO 1.5 ] 8 , 5a,10 and the para-substituted bis(3-aminopropyl) hexaisobutylsubstituted T 8 cage. 8 The energy levels of the LUMO+2 and LUMO+3 are almost degenerate, and a detailed analysis shows that the largest contribution to the MO in LUMO+3 comes from the atomic orbitals of silicon (5Si) at the para position to the Si atom substituted with the vinyl group in 1. Sum of squaring orbital coefficients for 5Si, the para position to the Si atom substituted with the vinyl group in 1, is larger than those of 3Si in LUMO+3 and 1Si,2Si,and 7Si in LUMO+2 (See Supporting Information).…”

“…8 The key stage of this route is the corner-opening of the completely condensed 3aminopropyl heptaisosbutyl-substituted T 8 cage with aqueous tetraethylammonium hydroxide (TEAOH), affording trisilanol aminopropyl hexaisobutyl-substituted T 8 cage as the predominant product. However, probability of other monofunctionalized T 8 cages for the corner-opening occurring at the para positions to the Si atoms substituted with the functional groups has not been studied.…”

Tripodal polyhedral oligomeric silsesquioxanes as a novel class of three-dimensional emulsifiers

“…From this point of view, polyhedral oligomeric silsesquioxanes (POSSs) [17][18][19][20][21] are one of the most suitable candidates because of their precisely defined three-dimensional structure. POSSs have been widely used as fillers, [22][23][24][25][26][27] cross-linkers, 28-33 monomers [34][35][36][37] and substituents to polymer side chains, [38][39][40][41][42][43] to attain high performance. To obtain a POSS emulsifier, the basic strategy is the construction of amphiphilic POSS derivatives.…”