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Eu(III)–Sr(II)–K(I) and Tb(III)–Sr(II)–K(I) heterotrimetallic metal-organic frameworks with 2,4,6-pyridinetricarboxylic acid have been synthesized under hydrothermal conditions. The complexes are isomorphic and both in triclinic space groupP-1. The ligands bond with three metal ions with two coordination modes. One connects seven metal ions and the other connects eight metal ions. IR spectra, thermal analysis, and photoluminescent properties have been studied. The results display strong characteristic emissions of Eu(III) or Tb(III) ions with excitation of ultraviolet radiation. [ABSTRACT FROM PUBLISHER]

Four transition metal complexes with Schiff base and 1,10-phenanthroline, [Cu(L)(phen)]2·C2H5OH (1), [Zn(L)(phen)]2·C2H5OH (2), [Ni(L)(phen)]2·C2H5OH (3), and [Co(L)(phen)]2·C2H5OH (4) (H2L = 1-((2-hydroxynaphthalen-1-yl)methylene)thiosemicarbazide; phen = 1,10-phenanthroline) were synthesized and characterized by physico-chemical methods. The crystal structure of1was determined by X-ray single-crystal diffraction analysis.1crystallizes in the orthorhombic space groupPbcawitha = 15.008(9),b = 16.100(10),c = 37.54(2) Å,V = 9070(10) Å3,Z = 8,GOOF = 1.002,R1 = 0.0626, andwR2 = 0.0912. The fluorescence and urease inhibitory activities of the compounds were tested. The enzymatic activity study indicated that3possessed potent inhibition againstjack beanurease, with IC50 = 1.2 ± 0.1 μM, and about 35 times more than 42.1 ± 0.4 acetohydroxamic acid as positive reference. This suggests that inhibitory efficiency of these complexes can be strongly influenced by different transition metal ions. [ABSTRACT FROM AUTHOR]

Three coordination polymers, [Ag4(bpy)3(pztc)] n (1), {[Ag6(bpy)2(pztc)(CN)2] · 2.6H2O} n (2), and {[Ag2(H2pdtc)(bpy)2] · 3H2O} n (3) (H4pztc = pyrazine-2,3,5,6-tetracarboxylic acid, H4pdtc = pyridine-2,3,5,6-tetracarboxylic acid, bpy = 4,4′-bipyridine), have been synthesized and characterized by elemental analysis, IR spectra, thermogravimetric analysis, UV spectra, fluorescent spectra, and single-crystal X-ray diffraction. Complex 1 displays a 3-D network with infinite channels of about 6.4 × 3.1 Å2 along the a-axis. The structure of 1 can be simplified as a 3,4,4-connected framework. Complex 2 displays a 3-D network and can be simplified as a 6,6-connected pcu framework. Complex 3 shows a 1-D chain structure and the chains form a 2-D layer structure by hydrogen bonds. Complexes 1–3 emit intense fluorescence at around 500 nm on excitation at 340 nm, 320 nm, and 340 nm, respectively. [ABSTRACT FROM AUTHOR]

The reaction of the decadentate ligand tpmen (H4tpmen = N,N,N'N'-tetrakis[(6-carboxypyridin-2-yl)methyl]ethylenediamine) with MnCl2·4H2O in aqueous solution gives a homodinuclear complex [Mn2(H2O)2(tpmen)]·16H2O, which has been characterized by elemental analysis, thermal gravimetric and single-crystal X-ray diffraction analysis. The complex crystallizes in the orthorhombic system, space group Cmca, a = 28.786(5) Å, b = 11.5033(19) Å, c = 14.437(2) Å, Z = 8, R1 = 0.0432, wR2 = 0.0786. The tpmen ligand contains four picolinate groups, two of which bind each Mn(II) to form a dinuclear complex. The geometry around the Mn(II) is distorted octahedral with two nitrogen and two oxygen atoms from the picolinate groups and two oxygen atoms from coordinated water. The variable-temperature (2-300 K) magnetic susceptibilities shows an antiferromagnetic interaction between Mn(II) ions. [ABSTRACT FROM AUTHOR]