The effect of the position of cross-linkers on the structure and microenvironment of PPh3 moiety in porous organic polymers

Three trivinyl functionalization triphenylphosphine (3vPPh3)-based porous organic ligands (3vPPh3-POLs) with cross-linkers in different positions were obtained through solvothermal polymerization. By simply changing the position of the cross-linkers (vinyl groups) attached to the PPh3 monomer, the resulting porous organic polymer (POP) materials acquired diverse hierarchical porous structures, and the microenvironment of POPs was sequently regulated. Among the three 3vPPh3-POLs, the BET surface areas ranged from 168 to 1583 m2 g−1, while the proportion of micropores changed from 0.0% to 52.0%. Benefiting from the unique structure, Rh ions could be coordinated and dispersed as a single site in m-3vPPh3-POL to form HRh(CO)2(PPh3-POL)2 species, which endowed the Rh/m-3vPPh3-POL catalyst with an activity similar to that in the homogeneous system, an l/b ratio (the ratio of the linear aldehyde to the branched aldehyde) approximately as high as 10, and stability for a duration of more than 500 h in the hydroformylation of 1-octene.