A Polymer-Oriented Synthesis Of Triazinyl Functionalized Mesoporous Organic Polymer Encapsulating Uitrafine Metal Clusters for Alkynes Semi-Hydrogenation.

Preparation of highly dispersed ultrafine metal clusters (MCs)- based catalysts with good stability and preeminent catalytic performance is a challenging problem for heterogeneous catalysis. Herein, we design and controllably synthesize a triazinyl functionalized mesoporous organic polymer (TRI-MOP) through a polymer-oriented synthesis strategy using polyethyleneimine (PEI) as pore-forming agent. The obtained TRI-MOP material possesses abundant worm-like mesopores, rich triazinyl groups, and high stability. Ultrafine Pd clusters with a small size (≈0.76 nm) are successfully anchored in the mesoporous channel of TRI-MOP by a simple impregnation-reduction approach. The as-prepared Pd@TRI-MOP catalyst exhibits excellent catalytic activity (96%) and selectivity (97%) in the semi-hydrogenation of phenylacetylene under very mild reaction conditions. The exceptional performance of Pd@TRI-MOP catalyst is attributed to the small size effect of Pd clusters, the electron coupling effect between the supports and the Pd and enriched meso-scaled pores. Therefore, this work provides a new platform for designing and preparing stable functional porous organic polymer materials to confine size-controlled MCs with superior catalytic performance for diversified potential catalysis applications.