Synthesis, Characterization, and Reaction of Divinyl-Substituted Laddersiloxanes

Silsesquioxanes with well-defined structures have been of great interest recently because of their superior properties. Among them, laddersiloxanes (ladder-type silsesquioxanes with defined structure) are less explored because step-by-step synthesis is usually necessary. In order to investigate the properties of laddersiloxanes, and apply these compounds as monomer precursors to high function materials, we prepared laddersiloxanes with reactive vinyl groups. The target compounds were obtained in a two-step reaction from commercially available alkoxysilanes, and total yields were 73–93 %. Three product stereoisomers were fully investigated by spectroscopic methods and structures were determined. As an extension of our previous research on constructing new laddersiloxanes, we will describe here the synthesis, characterization, and functionalization of novel divinyl-substituted laddersiloxanes. Further transformation of all products proceeded smoothly, and extended laddersiloxanes were obtained by hydrosilylation. One isomer was isolated and the structure was determined unequivocally by X-ray analysis. The laddersiloxanes described here have two reactive vinyl groups at each end of the molecule. Various reactions including hydrosilylation, polymerization, or olefin metathesis are possible, thus these compounds can be potential monomers for highly functionalized materials.