Title : Multifunctional silsesquioxane derivatives synthesis and characterization
Abstract:
Polyhedral oligomeric silsesquioxanes (POSS) are among the most intriguing examples of well-defined, nanostructured, functionalized building blocks, which find applications in academia and industry. They have been used in the synthesis of an enormous number of hybrid (co)polymers and nanocomposites characterized by complex composition, different functionalization, and architecture. Recently, much interest has arisen in silsesquioxanes bearing conjugated groups which are often called alkenyl-silsesquioxanes. Up to date, they have been used in the synthesis of porous and biomaterials, liquid crystals, fuel cells, semiconductors, as well as organic (OLED) or polymer electronics (PLED). One of the most versatile synthetic methods for the preparation of such systems is the hydrosilylation reaction. The process gives the possibility for selective formation of specific isomer during the Si-H addition. Moreover, the hydrosilylation can be performed in the wide range of temperatures, in different types of solvents, under air atmosphere, using easily available reagents, in the presence of stable and tolerable for many reactive functionalities or impurities catalysts. All of that makes it powerful tool which appropriately used can easily provide a wide spectrum of silsesquioxanes bearing various types of functionalities. In the communication we report studies on the hydrosilylation of a wide spectrum of terminal and internal alkynes with octafunctional spherosilicate (HSiMe2 O)8 Si8 O12, as well as 1,4-disubstituted-1,3-butadiynes, with monofunctional silsesquioxane (HSiMe2 O)(i-Bu)7 Si8 O12). This method permitted to obtain a series of new alkenyl-substituted spherosilicates, 3-en-1-ynes and 1,3-dienes with silsesquioxane moiety in high yields. The products were characterized by 1 H, 13C, 29Si NMR, FT-IR spectroscopy, ESI HR-MS spectrometry and X-ray crystallography. The influence of the reaction conditions (alkyne structure, type of the catalyst, solvent, temperature) on the process rate, its efficiency and selectivity will be presented.
