Abstract
Water pollution caused by organic dyes poses a significant threat to ecosystems and human health, underscoring the urgent need for sustainable degradation methods. We report two donor-π-acceptor conjugated microporous polymers (CMPs), Pyr-Ph-TzTz and Pyr-Th-TzTz, assembled from pyrene (Pyr) donors, phenyl or thiophene π-bridges, and thiazolothiazole (TzTz) acceptors. Precursors [4,4',4″,4‴-(pyrene-1,3,6,8-tetrayl)-tetrabenzaldehyde (Pyr-Ph-4CHO) and 5,5',5″,5‴-(pyrene-1,3,6,8-tetrayl)-tetrakis-(thiophene-2-carbaldehyde) (Pyr-Th-4CHO)] were synthesized via electrophilic bromination and Suzuki-Miyaura coupling with 4-formylphenylboronic acid (PFPBA), and 5-formyl-2-thienylboronic acid (5-FTBA); respectively. Pyr-Ph-4CHO and Pyr-Th-4CHO were each subjected to a one-pot condensation reaction with dithiooxamide, yielding robust, thermally stable CMPsPyr-Ph-TzTz and Pyr-Th-TzTzwith amorphous frameworks and surface areas of 37 and 20 m(2 )g(-1), respectively. UV-vis spectra reveal narrow band gaps of 2.02 eV for Pyr-Ph-TzTz CMP and 2.39 eV for Pyr-Th-TzTz CMP. Pyr-Ph-TzTz CMP exhibits markedly enhanced charge separation, as evidenced by pronounced PL quenching and ultraviolet photoelectron spectroscopy (UPS) analysis. Both CMPs adsorb rhodamine B (RhB) rapidly (equilibrium in 30 min; 55% removal by Pyr-Ph-TzTz CMP, 90% by Pyr-Th-TzTz CMP) and degrade it under visible light, achieving 96% (k = 0.0545 min(-1)) and 39% (k = 0.00341 min(-1)) removal, respectively. Radical scavenging and EPR identify •OH as the primary active species. Remarkably, Pyr-Ph-TzTz CMP retains >90% activity after five cycles, highlighting its promise for solar-driven dye removal.