Covalent organic polymer framework with C-C bonds as a fluorescent probe for selective iron detection

Abstract

A new carbon-carbon bonded nanoporous polymer network was synthesized via efficient and catalyst free Knoevenagel-like condensation polymerization in near quantitative yields. The obtained polymer network, Covalent Organic Polymer - COP-100 possesses strong fluorescent properties and designed solubility in polar aprotic solvents, which shows promise for use as a metal-sensing material in solution. COP-100 exhibited high selectivity towards Fe2+ and Fe3+ in the presence of other common metal cations (Al3+, Ag+, Cd2+, Co2+, Cr3+, cu(2+), Hg2+, mg2+, mn(2+), Nat, Ni2+, zn(2+)) as the fluorescence of the polymer was significantly quenched even at very low concentrations. In the range from 2.5 x 10(-6) to 2 x 10(-4) M, a linear fluorescence emission response with equipment limited detection minimum of 2.13 x 10(-7) M and 2.45 x 10(-7) M for Fe2+ and Fe3+, respectively, was observed. These results suggest that COP-100 is a promising material as a selective fluorescence sensor for iron ions.