Synthesis, structure, theoretical calculation and antibacterial property of two novel Zn(II)/Ni(II) compounds based on 3, 5-dichlorosalicylaldehyde thiocarbamide ligand.

Two new compounds namely [Zn(L1)phen]31 and Ni(L1)phen(MeOH) 2 (L1 = 3, 5-dichlorosalicylaldehyde thiosemicarbazone) were synthesized by the slow evaporation method at room temperature. The structure of ligand L1 was determined using 1H NMR and 13C NMR spectra. X-ray single crystal diffraction analysis revealed that compounds 1-2 can form 3D supramolecular network structures through π···π stacking and hydrogen bonding interactions. The DFT calculation shows that the coordination of ligand and metal is in good agreement with the experimental results. Hirshfeld surface analysis revealed that H…H and Cl…H interactions were the predominant interactions in compounds 1-2. Energy framework analysis indicated that dispersion energy played a dominant role in the energy composition of compounds 1-2. The inhibitory effects of compounds 1-2 against Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA) were tested using the paper disk diffusion method (1: E. coli: 18 mm, MRSA: 17 mm, 2: E. coli: 15 mm, MRSA: 16 mm). Ion releasing experiments were conducted to assess the ion release capacity of compounds 1-2 (Zn2+, 4 days, 38.33 µg/mL; Ni2+, 4 days, 29.12 µg/mL). Molecular docking demonstrated the interaction modes of compounds 1-2 with UDP-N-acetylenolpyruvoylglucosamine reductase (MurB) and dihydrofolate reductase (DHFR) in bacteria, involving hydrophobic, stacking, hydrogen bonding and halogen bonding interactions. The generation of reactive oxygen species (ROS) in bacteria under the presence of compounds 1-2 were evaluated using a fluorescent dye known as dichlorodihydrofluorescein diacetate (DCFH-DA). Potential antibacterial mechanisms of compounds 1-2 were proposed.

Synthesis, structure and photocatalytic property of a novel Zn(II) coordination polymer based on in situ synthetized pyridine-3,4-dicarboxylhydrazidate ligand.

One new pyridine-3,4-dicarboxylhydrazidate-coordinated compound [Zn(pdh)] 1 (pdh = pyridine-3,4-dicarboxylhydrazidate) was obtained under the hydrothermal conditions. Noteworthily, the pdh molecules in the title compound originated from the ligand in situ reaction between organic pyridine-3,4-dicarboxylic acid (pdca) and N2H4·H2O. X-ray single-crystal diffraction analysis revealed that the pdh ligands exhibit a special µ4-bridging mode in compound 1, which link Zn(II) centers into a 2D layered structure. The photocatalysis analysis indicates that it is a potential visible light catalyst. In addition, the solid photoluminescence property of compound 1 was also investigated.

Modified polyoxometalate: a novel monocapped bi-supporting and reduced α-Keggin structure {PMo12O40[Cu(2,2'-bpy)]}[Cu(2,2'-bpy)(en)(H2O)]2.

A novel modified polyoxometalate, {PMo12O40[Cu(2,2'-bpy)]}[Cu(2,2'-bpy)(en)(H2O)]2 [2,2'-bpy is 2,2'-bipyridyl (C10H8N2) and en is ethylenediamine (C2H8N2)], has been synthesized hydrothermally and structurally characterized by elemental analysis, TG, IR, XPS and single-crystal X-ray diffraction. The structural analysis reveals that the compound contains the reduced Keggin polyanion [PMo12O40]6- as the parent unit, which is monocapped by [Cu(2,2'-bpy)]2+ fragments via four bridging O atoms on an {Mo4O4} pit and bi-supported by two [Cu(2,2'-bpy)(en)(H2O)]2+ coordination cations simultaneously. There exist strong intramolecular π-π stacking between the capping and supporting units, which play a stabilizing role during the crystallization of the compound. Adjacent POM clusters are further aggregated to form a three-dimensional supramolecular network through noncovalent forces, hydrogen bonding and π-π stacking interactions. In addition, the photocatalytic properties were investigated in detail, and the results indicated that the compound can be used as a photocatalyst towards the decomposition of the organic pollutant methylene blue (MB).