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Exploring metal phosphonates with new crystal structures is of significance for the development of metal-organic frameworks (MOFs). In this work, two new copper phosphonates, [tetraauqa-1,4-phenylenebis(hydroxymethylene))bisphosphonate biscopper(II)] bishydrate [Cu2(H2L)(H2O)4]·2H2O (1) and 1,4-phenylenebis(hydroxymethylene))bisphosphonate-(4,4'-bipy) copper(II) [Cu(H4L)(4,4'-bipy)] (2) (4,4'-bipy = 4,4'-bipyridine), have been synthesized from a hydroxy functionalized bisphosphonate ligand, H6L = (1,4-phenylenebis(hydroxymethylene))bis(phosphonic acid). The introduction of a hydroxy group can regulate the crystal structures. The bisphosphonate ligand in 1 is hexadentate, binding six copper ions with its six phosphonate oxygen atoms and two hydroxy oxygen atoms, forming a three-dimensional framework structure with rectangle channels running along the b-direction. For 2, the bisphosphonate ligands are double deprotonated and chelate or bridge two copper ions, showing a two-dimensional layered crystal structure. These compounds have interesting fluorescence properties with emission maxima (307 and 410 nm) lying in the blue region. [ABSTRACT FROM AUTHOR]

One new uranyl tetracarboxylate, [UO2(H2L3)(H2O)]·3H2O, was synthesized hydrothermally from a methyl group decorated semi-rigid tetracarboxylic acid ligand and systematically characterized using powder and single-crystal X-ray diffraction, IR, EA, TGA, and luminescent methods. The four carboxylate groups in the carboxylic ligand were all monodentate bridging and the uranyl cations are linked by tetracarboxylic ligands to form a two-dimensional layered crystal structure. Introduction of methyl groups has a large effect on the speciation of uranyl carboxylates. The thermal behavior and luminescent properties are also investigated. [ABSTRACT FROM AUTHOR]

With the widespread application of neonicotinoid insecticides, Clothianidin has received much attention due to the potential harm to human health and ecological environment. However, the mechanism of Clothianidin's underlying toxicity to organisms remains unclear. In this work, the interaction between Clothianidin and human serum albumin was investigated and the intrinsic fluorescence of human serum albumin got quenched via static mechanisms upon the addition of Clothianidin. The binding constants between Clothianidin and human serum albumin at three different temperature were obtained to be 3.543 × 104, 2.995 × 104, and 2.490 × 104 M−1, respectively. Based on the van't Hoff equation, the thermodynamic parameters, ΔH0 and ΔS0 were estimated to be −53.885 KJ mol−1 and −110.535 J mol−1K−1, respectively. A single binding site was predicted from the binding constants at different temperatures by multiple spectroscopic techniques and the negative values of ΔH0 and ΔS0 indicated the binding of human serum albumin with Clothianidin was driven by hydrogen bonds or van der Waals forces. Furthermore, the loose and unfolded secondary structure of human serum albumin along with the addition of clothianidin had been observed through ultraviolet-visible absorption and circular dichroism spectra. In addition, it was also found that Clothianidin had polar effects of structural microenviroment not only on Trp but also Tyr residues from synchronous fluorescence analysis. This study illuminates the molecular mechanism of the interaction between human serum albumin and clothianidin for the first time and helps to construct a specific pesticide biosensor system of human health. [ABSTRACT FROM AUTHOR]