Triazine-based conjugated microporous polymers constructing triphenylamine and its derivatives with nitrogen as core for iodine adsorption and fluorescence sensing I2

Abstract

Abstract Three new triazine-based conjugated microporous polymers with nitrogen as cores containing triphenylamine (TPA), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (TDATA) and 4,4′,4″-tri[phenyl(m-tonyl)amino]triphenylamine moieties (TMDATA) (TTPA, TTDATA and TTMDATA) were constructed via Friedel-Crafts reaction catalysed by methanesulfonic acid. The resulting CMPs possess high BET surface area of over 308, 491 and 456\u202fm2\u202fg−1, large pore volumes, good stability, and display efficient and reversible guest uptake of 4.92, 4.72 and 4.49\u202fg\u202fg−1 in iodine vapour which are higher than that of the CMPs with benzene as core. Two ways to release the adsorbed iodine were explored: either slow release into ethanol or quickly release upon heating (with a high degree of control). Spectral studies make us known that the strong affinity for I2 is mainly due to large porosity, a conjugated π-electron aromatic system, C N bonds, and propeller-like twisted structures. Furthermore, luminescent study indicated that TTPA exhibits high sensitivity to electron-deficient I2 via fluorescence quenching. TTPA shows the largest amount of iodine adsorption and was the first CMP used fluorescence sensing iodine.