Direct Metal-Free Synthesis of Uracil- and Pentaazaphenalene-Functionalized Porous Organic Polymers via Quadruple Mannich Cyclization and Their Nucleobase Recognition Activities

The development of new interconnections and synthetic approaches for the formation of porous organic polymers (POPs) is a challenging endeavor. Herein, we report a facile gram-scale approach for the synthesis of uracil- and pentaazaphenalene-functionalized porous organic polymers (Ur-POPs), namely, Ur-TPA, Ur-TPB, Ur-TPP, and Ur-TPT POPs, through a one-pot quadruple Mannich polycondensation of 6-aminouracil with paraformaldehyde and triamine linkers having various degrees of planarity, without the need for any additives such as templates and catalysts. Interestingly, the obtained Ur-POPs exhibited a uniform rod-like morphology, and depending on the planarity of the triamine linkers, a diameter variety of the rod was observed. These Ur-POPs possessed high specific surface areas, as high as 360 m²g^-1, and high thermal stability. In addition, the presence of uracil units in the primary skeleton of Ur-POPs combined with their regular rod-like structures endowed them with superior capabilities for remarkable selective recognition toward adenine in an aqueous solution.