Functionalization of Silicon Surfaces Using SI-ATRP and Click Chemistry for Anchoring Asymmetric Catalysts

A novel approach for the surface-initiated atom transfer radical polymerization (SI-ATRP) of methoxyethyl methacrylate (MEMA) and 3-azidopropyl methacrylate (AZMA) on macroporous silicon substrates and their postfunctionalization by click chemistry with asymmetric catalysts is presented. Crystalline silicon was first used to monitor the multistep functionalization by quantitative IR-ATR spectroscopy. The attachment of an alkynyl FTIR marker on crystalline silicon demonstrated the effectiveness of the methodology, which was then applied onto macroporous silicon to anchor an enantiopure chromium-salen complex as a first step toward the development of new supported asymmetric organometallic catalysts on silicon-based materials. SEM and EDS measurements clearly show good homogeneity of the polymer growth through the porous layers with a uniform distribution of the catalysts (even deep inside the pores). The successful functionalization of macroporous silicon has confirmed the transferability of the technique to porous materials, highlighting its potential for application to even larger surface area substrates in future catalytic studies.