Highly fluorescent selectivity of two Cd(II) coordination networks with active sites for nitroaromatic compounds and Fe3+ and Hg2+

Abstract

Based on 5,5′-(1,3,6,8-tetraoxobenzo[lmn][3,8] phenanthrolin-2-7-diyl)bis-1,3- benzenedicarboxylic acid (H4BIPA-TC), two novel 2D coordination polymers, formulated as {[Cd(BIPA-TC)0.5(1,4-bib)(H2O)]·(H2O)3.5}n (1) and {[Cd2(BIPA-TC)(4,4′-bibp)(H2O)]·(H2O)}n (2) have been solvothermally synthesized with the help of two bis(imidazole) linkers, 1,4-bib and 4,4′-bibp(1,4-bib = 1,4-bis(benzimidazo-1-ly)benzene and 4,4′-bibp = 4,4′-bis(imidazolyl)biphenyl). Single-crystal X-ray diffraction analysis shows that complex 1 is a (4,4)-connected bilayer network structure with the point symbol of (46·48)2(42·64), which further expand into an interestingly 2D + 2D → 3D interweaved framework. Complex 2 possesses a (4,6)-connected network with two kinds of {Cd2(COO)2} SBUs with the point symbol of (32·42·52)(34·44·54·63), which further pack into a 3D supramolecular architecture through hydrogen bonds. Furthermore, the luminescent recognition properties of 1 and 2 for small organic molecules, nitroaromatic compounds, and metal cations have been explored systematically.