Hybrid Silica Gels Containing 1,3-Butadiyne Bridging Units. Thermal and Chemical Reactivity of the Organic Fragment

TLDR: In this article, the chemical reactivity of the hybrid organic−inorganic gel was studied and used as a tool for the study of the organization of the solid induced by the organic moieties.

Abstract: Silica gel containing diyne units have been obtained from molecular organosilicon precursors and the properties associated to the very reactive unsaturated organic moieties have been explored. The sol−gel polymerization of 1,4-bis(trimethoxysilyl)-1,3-butadiyne ((MeO)3SiC⋮CC⋮CSi(OMe)3) quantitatively led to a silsesquioxane network, [O1.5SiC⋮CC⋮CSiO1.5]n, consisting of siloxanes chains with bridging diyne units. The derived xerogels were characterized by IR and 13C and 29Si CP MAS NMR spectroscopies. The major environment of the Si atom corresponded to a T2 CSi(OR)(OSi)2 substructure, and only minor Si−C bond cleavage occurred during the sol−gel condensation. The chemical reactivity of the hybrid organic−inorganic gel was studied and used as a tool for the study of the organization of the solid induced by the organic moieties. Upon heating, in the solid state, the diyne fragments undergo a polyaddition to give an ene−yne structure. The polymerization, observed in the solid state, suggests favorable arrang...