Collaborative fabrication of poly(L-proline)s with well-defined mesopores and hydrophobicity: Synergistic effect of mesoporous confinement and hydrophobic micro-environment on organic transformations

The preparation of materials with a well-defined mesoporous structure and hydrophobicity is of great significance for heterogeneous catalyst development, yet there still remains a challenge for fabricating the above materials without using templates. Herein, the polymerization of L -proline-functionalized monomer with crosslinkers containing variable alkyl-bridged length (n = 2,4,6,8) and vinyl-modified Fe 3 O 4 nanoparticles to construct mesoporous poly( L -proline)s (MPLPs) has been reported for the first time. The resultant MPLPs were analyzed by characterization methods, suggesting that MPLPs with a well-defined mesoporous structure and unique hydrophobicity were successfully constructed by synergistic regulation of vinyl-modified Fe 3 O 4 nanoparticles and crosslinkers with alkyl-bridged length of 6 carbon atoms, in which vinyl-modified Fe 3 O 4 nanoparticles as structural reinforcer plays a vital role for the mesoporous formation. Moreover, the resultant MPLPs were found to be efficient catalysts for one-pot synthesis of functionalized spiroindolones and olefins. The kinetic study and the water contact angle indicate the mesoporous confinement and hydrophobic micro-environment in organic transformations. Hence, the high activity of MPLPs is ascribed to synergistic effect of mesoporous confinement and hydrophobic micro-environment, and the adsorption experiment results further confirm this synergistic catalysis. This work promotes a textural engineering approach to the development of multifunctional materials with well-defined mesopores and hydrophobicity.