ABSTRACT
The discovery of Periodic Mesoporous Organosilicas (PMOs) [1-3] with organic bridging groups incorporated in their silica framework has been the start of a fascinating research area which provides materials with huge potential [4-6]. Different organic bridges have been employed for very diverse applications, such as heterogeneous catalysts [7,8], bio-sensors [9,10], chromatographic packing materials [11,12], low-k materials [13,14], adsorbents of pollutants [15] and controlled drug delivery systems [16-19]. PMOs are highly porous materials with large specific surface areas, pore volumes and narrow pore size distributions. Furthermore, they exhibit a high thermal and mechanical stability [20-22], especially in comparison with other porous silica materials [23]. This type of material is
synthesized with structure directing agents such as the non-ionic triblock copolymer P123. Around this template, a silica source is condensed in basic or acid aqueous environment. Usually, an organo bis-silane (R′O)3-Si-R-Si-(OR′)3 is used where R represents the organic bridging group and R′ usually a methyl or ethyl group. Already many reports have appeared on different bridging groups (R) like phenylene, ethylene, ethenylene and ethylbenzene but also more complex and flexible organic functionalities have been described. Furthermore the bridging group can be modified to fine-tune the material for a specific application such as solid acid catalysis [4].
