Facile Synthesis of Hybrid Silica Nanoparticles Grafted with Helical Poly(phenyl isocyanide)s and Their Enantioselective Crystallization Ability

Abstract

In this contribution, we report on the facile synthesis of hybrid silica nanoparticles grafted with helical poly(phenyl isocyanide)s via both “grafting from” and “grafting to” strategies. First, triethoxysilanyl functionalized alkyne–Pd(II) initiator was anchored onto the surface of bare silica nanoparticles through silanization coupling reaction. Polymerization of phenyl isocyanide using the Pd(II)–anchored silica nanoparticles lead to the formation of hybrid nanoparticles grafted with helical poly(phenyl isocyanide)s. The surface-initiated polymerization was revealed to proceed in a living/controlled chain-growth manner, afforded the hybrid nanoparticles with controlled thickness. 31P NMR analysis indicated the initiation efficiency of the surface-anchored Pd(II) initiators is very high, and almost quantitative. The grafting density was determined to be ∼0.89 nm2/chain based on the thermal gravity analysis (TGA). Polymerization of optically active phenyl isocyanide bearing an l-alanine with a long decyl...