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A new compound of azotetrazole-3-hydroxy-2-naphthoic acid (H3ATNA) has been successfully synthesized and characterized. By controlling the ratio of metal ions to the ligand and the pH value of solution, mononuclear, dinuclear and tetranuclear dysprosium(III) complexes [Et3NH]3[Dy(HATNA)3]·5H2O (1), [Dy2(HATNA)3(DMF)(H2O)]·2DMF·CH3OH·2H2O (2) and [Et3NH]6[Dy4(ATNA)6(H2O)2]·DMF·2CH3CN·8H2O (3) were synthesized and characterized by X-ray diffraction crystallography (DMF = N,N-dimethylformamide). Crystallographic data demonstrate that the neutral H3ATNA exists as a hydrazone tautomer. Complex 1 is a mononuclear structure, in which the Dy(III) ion is a nine-coordinated ion surrounded by three tridentate HATNA− ligands. Complex 2 shows a dinuclear structure, which is bridged by three μ1,1-hydroxyl groups of three HATNA− ligands. In complex 2, the Dy(III)1 ion is a nine-coordinated ion surrounded by three tridentate HATNA− ligands, while Dy(III)2 is an eight coordinated atom with three tridentate HATNA− ligands, one DMF and one water molecule. Complex 3 displays a tetranuclear structure, which can be approximately considered as two μ1,3-carboxyl groups of ATNA3− ligands linking complex 2. The magnetic properties of 1–3 were investigated. Complexes 2 and 3 display slow magnetic relaxation in a zero dc field. [ABSTRACT FROM AUTHOR]

A new salamo-type bisoxime compound H3L has been synthesized and exploited as a highly efficient chemosensor with multiple responses to Cu2+ and S2−. Chemosensor H3L exhibits highly selective and sensitive detection of Cu2+ and S2− simultaneously. The LODs of Cu2+ and S2− were calculated to be 1.5398 × 10−7 and 1.7274 × 10−7 M in DMF-water (9 : 1, v/v) solution, respectively. The color of the chemosensor H3L solution changed from light green to dark green after adding S2− under a 365 nm UV-lamp. The sensing mechanism of the chemosensor H3L was characterized using several methods, including ultraviolet spectroscopy, ESI-mass spectrometry, 1H-NMR and FT-IR spectroscopy. Meanwhile, the crystal structure of the Cu(II) complex, [Cu2(L)]ClO4·2CH3OH, has been determined by X-ray crystallographic analysis. Density Functional Theory (DFT) was employed to further understand the obtained experimental results. [ABSTRACT FROM AUTHOR]

Four 3-(tetrazol-5-yl)-5-(pyrid-2-yl)-1,2,4-triazole (H2TPT) based complexes of [Co2(TPT)2(H2O)2] (1), [Mn2(TPT)2(H2O)2] (2), [Mn(TPT)(H2O)2]n (3) and [Cu(TPT)]n (4) have been solvothermally synthesized and structurally characterized by X-ray single-crystal diffraction analysis. Complexes 1 and 2 display isostructural dinuclear structures, while complex 3 exhibits a 1D zigzag chain structure. The structural difference for 2 and 3 may be caused by 100 and 160 °C temperature-controlled conditions. Complex 4 is a 3D framework structure in which the Cu2+ ion is in square pyramid coordination geometry. Complexes 1–4 display good thermal stability evaluated by thermogravimetric analysis. Complexes 1 and 4 show very strong antiferromagnetic interactions. The electrocatalytic oxygen evolution of complexes 1–4 was tested under neutral conditions, which revealed that the four complexes possess electrocatalytic oxygen evolution activity. Complex 1 exhibits a current density of 10.0 mA cm−2 at a potential of 2.00 V (vs. RHE), presenting 50-fold improvement in specific activity over the glassy carbon electrode. [ABSTRACT FROM AUTHOR]

Reversible crystal-to-crystal transformation between a linear trinuclear Fe(ii) complex [Fe3(NH2-trz)6(SCN)5(H2O)] (SCN)·4H2O (1, NH2-trz = 4-amino-1,2,4-triazole) and a 1D chain [Fe3(NH2-trz)6(SCN)5]n(SCN)n (1a) and the SCO behaviour change have been studied by X-ray single-crystal diffraction, magnetic measurements and DSC. Complex 1a exhibits one more SCO step at a low temperature. [ABSTRACT FROM AUTHOR]

A new salamo-type bisoxime compound H3L has been synthesized and exploited as a highly efficient chemosensor with multiple responses to Cu2+ and S2−. Chemosensor H3L exhibits highly selective and sensitive detection of Cu2+ and S2− simultaneously. The LODs of Cu2+ and S2− were calculated to be 1.5398 × 10−7 and 1.7274 × 10−7 M in DMF-water (9 : 1, v/v) solution, respectively. The color of the chemosensor H3L solution changed from light green to dark green after adding S2− under a 365 nm UV-lamp. The sensing mechanism of the chemosensor H3L was characterized using several methods, including ultraviolet spectroscopy, ESI-mass spectrometry, 1H-NMR and FT-IR spectroscopy. Meanwhile, the crystal structure of the Cu(II) complex, [Cu2(L)]ClO4·2CH3OH, has been determined by X-ray crystallographic analysis. Density Functional Theory (DFT) was employed to further understand the obtained experimental results. [ABSTRACT FROM AUTHOR]