Pyrene Bearing Azo-Functionalized Porous Nanofibers for CO(2) Separation and Toxic Metal Cation Sensing

[Image: see text] A novel luminescent azo-linked polymer (ALP) has been constructed from 1,3,6,8-tetra(4-aminophenyl)pyrene using a copper(I)-catalyzed oxidative homocoupling reaction. The polymer displays high porosity with a Brunauer–Emmett–Teller surface area of 1259 m(2) g(–1) and narrow pore size distribution (1.06 nm) and is able to take up a significant amount of CO(2) (2.89 mmol g(–1)) at 298 K and 1.00 bar with a high isosteric heat of adsorption of 27.5 kJ mol(–1). Selectivity studies applying the ideal adsorbed solution theory revealed that the novel polymer has moderately good selectivities for CO(2)/N(2) (55.1) and CO(2)/CH(4) (10.9). Furthermore, the ALP shows fluorescence quenching in the presence of Hg(2+), Pb(2+), Tl(+), and Al(3+) ions. Compared with these ions, the ALP showed no sensitivity to light metal ions such as Na(+), K(+), and Ca(2+) in ethanol–water solution, clearly indicating the high selectivity of the ALP toward heavy metal ions. The exceptional physiochemical stability, high porosity, and strong luminescence make this polymer an excellent candidate as a fluorescent chemical sensor for the detection of heavy metal ions.