Metal-organic frameworks with 1,4-di(1H-imidazol-4-yl)benzene and varied carboxylate ligands for selectively sensing Fe(iii) ions and ketone molecules.

Abstract

Four new metal-organic frameworks (MOFs) [Zn(L)(bpdc)]·1.6H2O (1), [Co(L)(bpdc)]·H2O (2), [Ni3(L)2(bptc)2(H2O)10]·2H2O (3) and [Cd2(L)(Hbptc)2] (4) were achieved by reactions of the corresponding metal salt with mixed organic ligands of 1,4-di(1H-imidazol-4-yl)benzene (L) and 4,4'-benzophenonedicarboxylic acid (H2bpdc) or biphenyl-2,4',5-tricarboxylic acid (H3bptc). They exhibit varied structures: MOFs 1 and 4 are porous three-dimensional (3D) frameworks, while 2 is an infinite one-dimensional (1D) chain and 3 is a two-dimensional (2D) network. Remarkably, 1 and 4 can act as potential fluorescent materials for sensing Fe(iii) ions and different ketone molecules with high selectivity and sensitivity. In addition, MOF 1 shows selective adsorption of CO2 over N2.