New complexes driven by an unsymmetrical tetracarboxylate for highly selective detection of acetylacetone in aqueous solution

Abstract

Two novel complexes based on an unsymmetrical tetracarboxylate, namely, [Cd2(bptc)(bpp)(H2O)2]n·nH2O (1, H4bptc ​= ​2,3,3′,4′-biphenyl tetracarboxylic acid; bpp ​= ​1,3-bis(4-pyridyl) propane), [Cu(H2bptc)(phen)] (2, phen ​= ​1,10-phenanthroline) have been solvothermally synthesized with the aid of N-donor ligands. The structures, CHN analysis, IR analysis, thermal stabilities and photoluminescence properties of title complexes were investigated. Single-crystal X-ray diffraction analysis indicates that complex 1 demonstrates a novel 3-D network with (4, 5, 5) -connected (3ˑ4ˑ5ˑ6ˑ82) (3ˑ42ˑ5ˑ63ˑ83) (3ˑ43ˑ52ˑ63ˑ7) topology. Whereas complex 2 only possesses a mononuclear structure. Photoluminescence studies indicate that complex 1 shows a strong green light emission, while 2 exhibits blue emissions. Moreover, the luminescence properties of 2 can be utilized to sensitively and selectively detect acetylacetone in aqueous solution with the detection limit of 61.3 ​ppb. In addition, the probable mechanisms are also detailedly investigated, which indicate that the static photo-competitive absorption, photoinduced electron transfer and H-bonding interaction between sensor and analyte may be the main reasons for the fluorescence quenching effect.