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In this work, a versatile multi-dentate 1,2-bis(pyridin-4-ylmethylene)hydrazine (L) ligand has been employed to construct three novel iron(II) coordination complexes, [Fe(L) 2 (NCS) 2 (H 2 O) 2 ]·2H 2 O ( 1 ), [Fe(L)(NCS) 2 (H 2 O) 2 ] ( 2 ) and {[Fe(L) 2 (NCS) 2 ]·2CH 3 OH} n ( 3 ) (NH 4 NCS = ammonium thiocyanate), which can be isolated under similar synthetic conditions, only different molar ratio of metal/ligand or different solvent systems are used. 1 is a mono-nuclear iron(II) coordination complex, and 2 is a one-dimensional (1D) iron(II) coordination complex, while 3 is a 2D micro-porous iron(II) framework with the channel dimensionality of 13.936(3) Å × 13.936(3) Å. PXRD patterns also confirm the purity of the bulky samples of 1 – 3 . For 1 – 3 , it represents the first example of solvent-induced drastic reversible dynamic conformation between different dimensional iron(II) coordination complexes 1 (0D), 2 (1D) and 3 (2D) (for 1 : water; for 2 : benzene; for 3 : methanol/acetone/acetonitrile), which are unambiguously confirmed by PXRD characterizations. Variable-temperature magnetic susceptibility data of 2 – 3 have been recorded in the 2–300 K temperature range, indicating weak antiferromagnetic interactions. [ABSTRACT FROM AUTHOR]

Abstract: Under hydrothermal conditions using cis-butenedioic acid (H2L) and corresponding lead(II) salts, a three-dimensional (3D) lead(II) complex {[Pb2(L)(μ2-Cl)(μ3-Cl)]} n (1) containing 3D Pb–X–Pb (X=O and Cl) linkage has been isolated. 1 also represents a truly 3D hybrid luminescent lead(II) framework with I 3 O 0 type connectivity. Further analysis reveals that cis- and trans-conformations of butenedioic acid ligand greatly affect the lead(II) framework structure. Solid-state fluorescence spectrum of 1 exhibits the maximum emission peak at 379nm. [Copyright &y& Elsevier]

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]

Abstract: Three complexes with different structures were obtained by reacting 2,3,5-pyridinetricarboxylic acid (H3pta) with d 9 (Cu2+) and d 10 (Zn2+,Ag+) ions in water at room temperature. The complexes of [Cu(H2pta)2(H2O)2]·2H2O (1) and [Zn2(Hpta)2(H2O)6]·4H2O (2) are mononuclear and binuclear structures, respectively; while [Ag(H2pta)(H2O)] n (3) is a helical 1D chain coordination polymer. A double chain was further formed in 3 by the weak interaction between oxygen atoms and Ag(I) ions. Through hydrogen bonds the three complexes constructed corresponding 3D network structures. The three complexes were characterized by elemental analyses, IR and single-crystal X-ray diffraction analyses. In addition, TGA, XRD and fluorescence spectra determinations were performed for compounds 2 and 3. [Copyright &y& Elsevier]

The construction of hierarchical nanostructures plays an important role in performance improvement and application expansion of advanced nanomaterials. The fabrication of three dimensional hierarchical graphene nanostructures (TGNs) with controlled primary building units and secondary structures is still a challenge in synthetic methodology, since it is difficult to achieve the necessary delicate arrangement of graphene. TGNs with controlled primary building units and secondary structures are realized here via a metal complex strategy. Ni-Based metal complexes with organic polybasic acid ligands are used as the precursors of the TGNs. The results show that the amount of Ni(CH3COO)2·4H2O determines the different morphologies and compositions of the metal complex precursors, which further determine the primary building units and secondary structures of the TGNs. The obtained TGNs can serve as excellent candidates for anode materials for lithium ion batteries to achieve superior electrochemical behaviors. [ABSTRACT FROM AUTHOR]

By using aryl-thiazoles as cyclometalated ligands and an oxadiazol-substituted amide as the ancillary ligand, three novel iridium(iii) complexes have been synthesized and characterized, and their photophysical and electrochemical properties have been investigated. Complexes 1–3 exhibit efficient phosphorescence emissions at 542, 555 and 585 nm with photoluminescence quantum yields (PLQYs) of 0.04, 0.03 and 0.02 in CH3CN solutions, respectively. In the 10 wt% doped 2,4-diphenyl-6-bis(12-phenylindolo)[2,3-a]carbazole-11-yl)-1,3,5-triazine (Dictrz) film, the PLQYs (0.88 for complex 1, 0.47 for complex 2 and 0.37 for complex 3) increase significantly owing to the great restriction of rotations and vibrations in the rigid host. The organic light-emitting diodes based on these complexes show good performance with maximum current efficiencies of 20.06, 22.20 and 13.45 cd A−1 and maximum power efficiencies of 13.54, 17.31 and 9.48 lm W−1 with CIE coordinates of (0.46, 0.53), (0.49, 0.50) and (0.59, 0.40) for complexes 1–3, respectively. [ABSTRACT FROM AUTHOR]

A cationic iridium complex [Ir(dfpmpy) 2 (pzpy)](PF 6 ) with 2-(1H-pyrazol-1-yl)pyridine as ancillary ligand has been prepared, and its crystal structure, photophysical and electrochemical properties have been investigated. In degassed CH 3 CN solution, this complex exhibits blue emission with a peak wavelength of 451 nm. Photophysical property indicates that photoluminescence of complex [Ir(dfpmpy) 2 (pzpy)](PF 6 ) originates mainly from ligand-centered 3 π → π ∗ states. In addition, solution-processed organic light-emitting diodes based on [Ir(dfpmpy) 2 (pzpy)](PF 6 ) have been fabricated. A blue light electroluminescence (484 nm) was observed and a maximum current efficiency of 1.56 cd A −1 corresponding to a maximum power efficiency of 0.33 lm W −1 , has been achieved. This demonstrates that this complex is a promising phosphor for achieving efficient electrophosphorescence in the blue light region. [ABSTRACT FROM AUTHOR]

The fabrication of sulfide/graphene composites is an important strategy to improve the performance of supercapacitors. It is still a challenge to synthesize three-dimensional sulfide/graphene nanostructures with special morphologies and structures because it is difficult to realize the effective arrangement of graphene. In this work, a simple method has been successfully developed for the fabrication of three-dimensional NiS 2 /graphene nanostructures. The rod-like morphology of the precursors is preserved during the carbonization and sulfurization process. The carbonization temperature can affect the size of NiS 2 nanoparticles formed in the nanostructures. The as-obtained materials can serve as electrode materials in supercapacitors and present excellent electrochemical behavior due to their good electrical conductivity and unique structures. [Display omitted] • Controlled synthesis of three-dimensional NiS 2 /graphene nanostructures. • Carbonization temperature affects the particle size of NiS 2 in the nanostructure. • NiS 2 /graphene nanostructures present superior electrochemical performance. [ABSTRACT FROM AUTHOR]

Three new yellow-emitting cationic iridium complexes have been prepared, and the photophysical and electrochemical properties have been investigated. These cationic iridium complexes have excellent thermal stability and can be thermally vacuum-sublimed as phosphorescent dyes for the fabrication of efficient organic light-emitting diodes. The devices based on these complexes give yellow-green electroluminescences with Commission Internationale de L'Eclairage coordinates of (0.38, 0.58), (0.37, 0.58), (0.38, 0.58). The maximum current efficiencies of devices based on these complexes are 20.2, 23.7 and 21.5 cd A −1 that corresponds to maximum external quantum efficiencies of 6.3%, 6.8% and 6.5%, respectively. [ABSTRACT FROM AUTHOR]

Ni(L)2 (1) and Zn2(μ-OL)2(L)2 (2), (HL=S-benzyl-β-N-(2-bromobenzylidene) dithiocarbazate), were synthesized and characterized by elemental analysis and X-ray single-crystal diffraction analysis. 1 is a mononuclear neutral nickel(II) complex and the center nickel atom is chelated by donors of N2S2 possessing a distorted tetrahedral configuration, while in 2, the adjacent two complex molecules are linked through two O atoms to form a dimer and the center zinc atom is five-coordinate in a distorted trigonal-bipyramidal geometry. The cytotoxic activity study indicated that 2 showed potent cytotoxic activity against the human liver hepatocellular carcinoma (HepG2) cancer cell lines, with IC50 2.4±0.2μg·mL−1, which is slightly weaker than 5-fluoroacil (5-FU) (0.89±0.21μg·mL−1) as reference. A gel electrophoresis assay demonstrated the ability of the complex to cleave the pBR322 plasmid DNA. [ABSTRACT FROM AUTHOR]

A rare earth ytterbium complex with 2,4,6-pyridinetricarboxylic acid (Hpta) has been synthesized by hydrothermal method, the formula is {[Yb(pta)(HO)]·HO}. The complex crystallized in monoclinic system, P2/c space group with lattice parameters a = 11.6556(19)Å, b = 7.8364(12), c = 22.020(4), α = γ = 90º, β = 92.120(3), Z = 4, GOF = 1.026, R1 = 0.0334, wR2 = 0.0660. The pta anions connect four rare earth Yb(III) ions with two different coordination modes. The complex exhibit intense characteristic near-infrared luminescence of Yb(III) ions at 990 nm with excitation of UV-rays. [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]