Carbamate-Isocyanurate-Bridged Periodic Mesoporous Organosilica for van der Waals CO Capture.

We synthesized a new organosiloxane bridge on the basis of an isocyanurate derivative through a simple melt-fusion approach by the reaction of 3-isocyanatopropyltriethoxysilane (IPTES) with 1,3,5-tris(2-hydroxyethyl)-1,3,5-triazinane-2,4,6(1,3,5)-trione (THEIC). The obtained carbamate-isocyanurate-based organosiloxane bridge precursor was used for the preparation of chemo- and thermostable periodic mesoporous organosilica (PMO-THEIC) on condensation with tetrathoxysilane silicon precursor through a soft-template approach. Furthermore, the synthesized PMO-THEIC with unique surface functionality was investigated for CO capture. The results show that the PMO-THEIC has higher activity than pure SBA-15 for CO capture due to the high affinity of carbamate functionalities embedded within the pore walls toward CO molecules. The affinity of organosiloxane bridge for CO molecules is mainly facilitated via the van der Waals force with carbamate functional groups rather than the isocyanurate ring, according to the density functional calculations.