A New 4-Connected Co(II) Coordination Framework With an Uncommon Two-Fold Interpenetrating Net: Synthesis, Structure and Luminescence Property

The coordination polymer [Co(pbc)₂(H₂O)]_n(Hpbc = 3-Pyrid-4-ylbenzoic acid) was prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction, FTIR spectra and element analysis. X-ray diffraction analysis reveals that the pbc⁻ ligands act as diconnectors to link two Co(II) centers and adopt a two coordination mode: μ ₂-N, O and μ ₂-N, O, O to form infinite wavy cobalt-carboxylate chains along the bc plane. Furthermore, compound, [Co(pbc)₂(H₂O)]_n, shows intense photoluminescence at room temperature.     

Crystal Structures and Effect of Temperature on the Luminescence of Two Lanthanide Coordination Polymers with Twofold Interpenetrating pcu Topology

Two new lanthanide coordination polymers formulated as [Ln(BDC)_1.5(DMF)(H₂O)] _n [Ln = Tb (1), Gd (2)] [H₂BDC = 1,4-benzenedicarboxylic acid, DMF = N,N′-dimethylformamide] were synthesized under solvothermal conditions. The coordination polymers were characterized by IR spectroscopy, elemental analysis and X-ray single-crystal diffraction. The two coordination polymers are isostructural and exhibit twofold interpenetrating pcu three-dimensional open frameworks constructed by tetradentate ligand of H₂BDC. The fluorescence properties of 1 and 2 were investigated at 298 or 77 K both in solid state and in CH₂Cl₂ solvent dispersed as suspensions. Coordination polymer 1 exhibits characteristic Tb³⁺ ions emission transitions of ⁵D₄ → ⁷F _J (J = 6–2) at 77 or 298 K both in the solid-state and in CH₂Cl₂ solvent. Moreover, the vibrational structure of 1 is more defined at 77 K, which exhibits another two ⁵D₄ → ⁷F₁ and ⁵D₄ → ⁷F₂ transitions more than that at 298 K. The lifetimes of 1 are longer at 77 K (915.2 μs in the solid state and 874.11 μs in the CH₂Cl₂ solvent) than that at 298 K (866.31 μs in the solid state and 801.04 μs in the CH₂Cl₂ solvent), which may be caused by the increase of radiative rate and decrease of non-radiative rate at low temperature. The singlet excited state (28,653 cm^?1) and the lowest triplet energy level (23,641 cm^?1) of H₂BDC ligand were calculated based on the UV–Vis absorbance edges of ligand and the phosphorescence spectrum of Gd³⁺ coordination polymer (2) at 77 K, showing that the effective extent of energy transfer from H₂BDC ligand to Tb³⁺ ion. Finally, thermal behaviors of the two coordination polymers were studied by thermogravimetric analysis, which exhibit thermal stability to 250 °C.     

In situ Synthesis,Crystal Structure and Photoluminescence of a Novel Coordination Polymer with (4,6,6)-Connected sqc111 Topology

Employing the mixed ligands to react with Cd(NO₃)₂·4H₂O afforded a new 3D coordination polymer [Cd₃(BPTC)(bmp)₂(ox)(H₂O)₄] (1) (H₄BPTC?=?biphenyl-3,3′,4,4′-tetracarboxylic acid, bmp?=?3,6-bis(imidazol-1-yl)pyridazine, H₂ox?=?oxalic acid), in which ox^2? was from the in situ oxidation of ethanol. Compound 1 bears a novel trinodal (4,6,6)-connected net structure, and it is the first replica of the theoretically predicted sqc111 topology net. Moreover, the thermal and photoluminescent properties for 1 were also investigated.     

Synthesis,Crystal Structure and Luminescent Property of a New Zn(II) Coordination Polymer with Twofold Interpenetrated pcu Topology

A new Zn(II) coordination polymer; namely, [Zn(FA)(bmix)_0.5] _n ·nH₂O (1, H₂FA = fumaric acid, bmix = 1,4-bis(2-methyl-1H-imidazol-1-ylmethyl)benzene) was synthesized with fumaric acid and flexible 2-methylimidazole-based ligands with Zn(II) salts under hydrothermal conditions. Single-crystal X-ray diffraction reveals that 1 features a twofold interpenetrating three-dimensional pillar-layered framework based on paddle-wheel shaped [Zn₂(COO)₄] subunits. The structure may be simplified to a 6-connected pcu topological network. Luminescent investigation reveals that 1 exhibits intense ligand-centered fluorescence at room temperature.     

A Three-Dimensional Cd(II)-Coordination Polymer: Crystal Structure,Electrochemiluminescent Property and Novel Topology

Journal of Inorganic and Organometallic Polymers and Materials - By employing 5-(pyridin-3-yl)-1H-pyrazole-3-carboxylic acid ligand, a new coordination polymer [Cd(HPPC?)2(H2O)2]n (1) has...     

A Novel Binodal (4,9)-Connected 3D Calcium Coordination Polymer: Synthesis, Characterization, Thermal Stability and Luminescent Properties

A novel coordination polymer, namely, [Ca₃(BIPA)₃(H₂O)₃·H₂O] _n (1) has been prepared by the reaction of 5-bromoisophthalic acid (H₂BIPA) with corresponding Ca(II) ions, and characterized by single-crystal X-ray diffraction, element analysis, infrared spectroscopy, thermogravimetric analysis In compound 1, a trimer unit [Ca₃O₁₉] is bridged the carboxylate oxygen atoms, forming an inorganic layer structure. The inorganic layers are linked by the BIPA^2? ligands, resulting in a three-dimensional (3D) pillared layered structure with a binodal (4,9)-connected 3D net structure with Schläfi symbol of (3⁴·4²)(3⁸·4¹⁰·5¹²·6⁶). In compound 1, the carboxylate groups of the BIPA^2? ligands coordinate to calcium ions using different coordinated modes. In addition, the thermal stability and luminescent properties of 1 were also investigated.     

Down-Regulation of Porcine Heart Diaphorase Reactivity by Trimanganese Hexakis(3,5-Diisopropylsalicylate), Mn(3)(3,5-DIPS)6, and Down-Regulation of Nitric Oxide Synthase Reactivity by Mn(3)(3,5-DIPS)(6) and Cu(II)(2)(3,5-DIPS)(4)

Purposes of this work were to examine the plausible down-regulation of porcine heart diaphorase (PHD) enzyme reactivity and nitric oxide synthase (NOS) enzyme reactivity by trimanganese hexakis(3,5-diisopropylsalicylate), [Mn(3)(3,5-DIPS)(6)] as well as dicopper tetrakis(3,5- diisopropylsalicylate, [Cu(II)(2)(3,5-DIPS)(4)] as a mechanistic accounting for their pharmacological activities.Porcine heart disease was found to oxidize 114 muM reduced nicotinamide-adenine- dinucleotide-'(3)-phosphate (NADPH) with a corresponding reduction of an equivalent concentration of 2,6-dichlorophenolindophenol (DCPIP). As reported for Cu(II)(2) (3,5-DIPS)(4), addition of Mn(3)(3,5-DIPS)(6) to this reaction mixture decreased the reduction of DCPIP without significantly affecting the oxidation of NADPH. The concentration of Mn(3)(3,5-DIPS)(6) that produced a 50% decrease in DCPIP reduction (IC(50)) was found to be 5muM. Mechanistically, this inhibition of DCPIP reduction with ongoing NADPH oxidation by PHD was found to be due to the ability of Mn(3)(3,5-DIPS)(6) to serve as a catalytic electron acceptor for reduced PHD as had been reported for Cu(II)(2)(3,5-DIPS)(4). This catalytic decrease in reduction of DCPIP by Mn(3)(3,5-DIPS)(6) was enhanced by the presence of a large concentration of DCPIP and decreased by the presence of a large concentration of NADPH, consistent with what had been observed for the activity of Cu(II)(2)(3,5-DIPS)(4)Oxidation of NADPH by PHD in the presence of Mn(3)(3,5-DIPS)(6) and the absence of DCPIP was linearly related to the concentration of added Mn(3)(3,5-DIPS)(6) through the concentration range of 2.4 muM to 38muM with a 50% recovery of NADPH oxidation by PHD at a concentration of 6 muM Mn(3)(3,5-DIPS)(6)Conversion of [(3)H] L-Arginine to [(3)H] L-Citrulline by purified rat brain nitric oxide synthase (NOS) was decreased in a concentrated related fashion with the addition of Mn(3)(3,5-DIPS)(6) as well as Cu(II)(2)(3,5-DIPS)(4) which is an extention of results reported earlier for Cu(II)(2)(3,5-DIPS)(4). The concentration of these two compounds required to produce a 50% decrease in L-Citrulline synthesis by NOS, which may be due to down-regulation of NOS, were 0.1 mM and 8muM respectively, consistent with the relative potencies of these two complexes in preventing the reduction of Cytochrome c by NOS.It is concluded that Mn(3)(3,5-DIPS)(6), as has been reported for Cu(II)(2) (3,5-DIPS)(4) , serves as an electron acceptor in down-regulating PHD and both of these complexes down-regulate rat brain NOS reactivity. A decrease in NO synthesis in animal models of seizure and radiation injury may account for the anticonvulsant, radioprotectant, and radiorecovery activities of Mn(3)(3,5-DIPS)(6) and Cu(II)(2)(3,5-DIPS)(4).     

3D Pillar-Layered Zn(II) Compound with 6-Connected pcu Topology: Synthesis,Structure and Luminescent Properties for Sensing of Nitrobenzene

A new Zn(II) compound, namely {[Zn(atz)(C₂O₄)_0.5]·H₂O}_n (1 Hatz = 3-amino-1,2,4-triazole), has been synthesized by the hydrothermal reactions of Zn(NO₃)₂, Hatz and H₂C₂O₄. Single crystal X-ray structure analysis reveals that compound 1 features a 3D porous pillar-layer structure with 6-connected pcu topology. The free water molecules are filled in the 1D channels. Thermal analysis reveals that it can be stable up to 347 °C. Luminescence investigation for 1 reveals that it can be used as a good candidate for sensing of nitrobenzene.     

Novel two-dimensional Co(II) and Cd(II) coordination polymers with intriguing net topologies

Three new two-dimensional coordination polymers were constructed from 2,6-bis(imidazole-1-yl)pyridine (2.6-bip), terephthalic acid (1,4-bdcH₂), and M(NO₃)∙nH₂O (M = Co, Cd). [M(2,6-bip)(1,4-bdc)] (1: M = Co; 2: M = Cd) were prepared under hydrothermal condition, whereas [Cd(2,6-bip)(1,4-bdc)∙xDMF] (3) was obtained under solvothermal condition in DMF solvent. Single-crystal X-ray analyses revealed the first example of a 2D 4-connected net of 6⁶ topology in 1 and 2 and a rare 2D 4,5-connected net of 4,5 L20 topology in 3. All these complexes were thermally robust and emissive in solid-states. This work confirmed the versatility of using hingelike 2,6-bip as a linker and the importance of solvent effect in the process of framework formation.     

Calcium(II)(3) (3,5-Diisopropylsalicylate)(6)(H(2)O)(6) Activates Nitric Oxide Synthase: An Accounting for its Action in Decreasing Platelet Aggregation

Purposes of these studies were first; to determine whether or not Calcium(II)(3) (3,5- diisopropylsalicylate)(6)(H(2)O)(6) [Ca(II)(3)(3,5-DIPS)(6)], a lipophilic calcium complex, could decrease activated-platelet aggregation, and second; to determine whether or not it is plausible that Ca(II)(3)(3,5-DIPS)(6) decreases activated-platelet aggregation by facilitating the synthesis of Nitric Oxide (NO) by Nitric Oxide Synthase (NOS). The influence of Ca(II)(3)(3,5-DIPS)(6) on the initial rate of activated-platelet aggregation was determined by measuring the decrease in rate of increase in transmission at 550 nm for a suspension of Thrombin-CaCl(2) activated platelets following the addition of 0, 50, 100, 250, or 500 muM Ca(II)(3)(3,5-DIPS)(6). To establish that the Ca(lI)(3)(3,5- DIPS)(6)-mediated decrease in aggregation was due to activation of NOS, the effect of L-NMMA, an inhibitor of NOS, on the inhibition of platelet aggregation by Ca(II)(3)(3,5-DIPS)(6) was determined using a suspension of activated platelets contaimng 0 or 250 muM Ca(II)(3)(3,5-DIPS)(6) without or with 1 mM L-NMMA. An in vitro Bovine Brain NOS reaction mixture, containing CaCl(2) for the activation of Phosphodiesterase-3' ,5'-Cyclic Nucleotide Activator required for the activation of NOS, was used to determine whether or not Ca(II)(3)(3,5-DIPS)(6) could be used as a substitute for the addition of Ca. The decrease in absorbance at 340 nm, lambda maximum for NADPH, was measured to determine NOS activity following the addition of NOS to the complete reaction mixture containing either CaCl(2), Ca(II)(3)(3,5-DIPS)(6), or neither Ca compound. Increasing the concentration of Ca(II)(3)(3,5-DIPS)(6) caused a concentration related decrease in activated platelet aggregation. The addition of L-NMMA to activated platelets, in the absence of Ca(II)(3)(3,5-DIPS)(6), caused a 129% increase in initial rate of platelet aggregation. The initial rate of platelet aggregation decreased 74% with the addition of 250 muM Ca(II)(3)(3,5-DIPS)(6) and the addition of L-NMMA plus 250 muM Ca(II)(3)(3,5-DIPS)(6) caused a 197% decrease in initial rate of aggregation compared to the initial rate observed width the presence of 1 mM L-NMMA alone. There was only a small, 27%, increase in initial rate of 0.4 mM NADPH oxidation when 0.9 mM CaCl(2) was added to the NOS reaction mixture in comparison to the initial rate of NADPH oxidation with no addition of CaCI(2). Addition of an equivalent amount of Ca in the form of Ca(II)(3)(3,5-DIPS)(6), 333 muM, caused a 37% increase in initial rate of NADPH oxidation compared to the addition of 0.9 mM CaCl(2). Addition of increasing concentrations of L-NMMA plus 0.9 mM CaCl(2) or 333 muM Ca(II)(3)(3,5-DIPS)(6) to the NOS reaction mixture caused a concentration related increase in initial rate of NADPH oxidation. Addition of L-NMMA while expected to decrease NADPH oxidation actually increased the rate of NADPH oxidation. Additions of 133 muM or 267 muM Ca(II)(3)(3,5- DIPS)(6) also caused concentration related increases in initial rate of NADPH oxidation in the presence of 113 muM L-NMMA. However, the addition of 533 muM Ca(II)(3)(3,5-DIPS)(6) caused a dramatic decrease in initial rate of NADPH oxidation by NOS. It is concluded that: 1) Ca(II)(3)(3,5- DIPS)(6) activates platelet NOS in preventing platelet aggregation, 2) in vitro NOS activity can be observed spectrophotometrically by following the consumption of NADPH as a decrease in absorbance at 340 nm, 3) Ca(II)(3)(3,5-DIPS)(6) plays a role in enhancing Bovine Brain NOS activity resulting in an increased rate of NADPH oxidation by NOS, 4) Ca(II)(3)(3,5-DIPS)(6) is a useful form of Ca in activating NOS and superior to CaCl(2) with regard to the facilitation of a NADPH oxidation, and 5) L-NMMA stimulates Bovine Brain NOS activity rather than causing an inhibition of this enzyme and must serve as a reducible substrate for Bovine Brain NOS.     

Synthesis,Crystal Structure and Luminescence Property of a New (6,3)-Connected Zn(II) Coordination Polymer

The 2D coordination polymer, [Zn(dpa)(bpp)] _n (H₂dpa = 2,4′-biphenyl-dicarboxylic acid, bpp = 1,3-di(4-pyridyl)propane) was prepared by hydrothermal synthesis in the presence of NaOH and characterized by single-crystal X-ray diffraction, FTIR spectra, element analysis and thermal analysis. The crystal structure determination reveals that the carboxylate groups of 2,4′-biphenyldicarboxylic acid are acting as bridging ligands and adopt two coordination modes; bis-monodentate and bidentate chelating. The network consists of a 2D (6,3)-connected architecture. At room temperature the solid-state luminescence spectrum of [Zn(dpa)(bpp)] _n shows a blue emission at about 354 nm upon excitation at 333 nm.     

A Novel 3D Europium (III) Coordination Polymer Constructed from 3,5-Pyridinedicarboxylate Acid: Synthesis, Crystal Structure and Emission Spectrum

Abstract  A novel 3D coordination polymer Eu₂(PDC)₃(H₂O)₃ (1) has been synthesized by hydrothermal reaction of europium chloride with 3,5-pyridinedicarboxylate acid (H₂PDC) under acidic condition (pH 2–3). Complex 1 is a 3D coordination polymer via 1D infinite chains built by the pyridinium moieties of the PDC²⁻ anions. The thermal analyses and luminescent properties of 1 have also been investigated. Graphical Abstract   A novel 3D coordination polymer Eu₂(PDC)₃(H2O)₃ has been synthesized by hydrothermal reaction of europium chloride with 3,5-pyridinedicarboxylate acid under acidic conditions (pH 2–3). The formation of the title complex demonstrates that pH plays an important role during the synthesis.      

Novel Cd(II) and Co(II) 2-D frameworks based on terephthalate and 1-substitutedimidazole mixed-ligands

The two Cd(II) and Co(II) 2-D frameworks have been prepared by means of self-assemblies of Cd(II) or Co(II) salts and 1-substituted imidazole and terephthalic acid, and structurally characterized by X-ray diffraction analyses. In complex 1 2-D frameworks with rhombic cavity are formed, in which the each top point of rhombus contains one hexa and two heptacoordinated Cd(II). In complex 2 2-D networks with rectangular cavities are formed, and the opposite benzene rings from carboxyls in each rectangular cavity are parallel.     

A New Cd(II) Coordination Polymer with a Rare tfz-d Topology Constructed by Asymmetrically Tricarboxylate and Imidazole-Containing Ligand: Synthesis,Crystal structure and Luminescent Property

A new coordination polymer [Cd(Hbtc)(bib)_0.5] _n (1) (H₃btc = biphenyl-3,4′,5-tricarboxylate and bib = 1,4-bis(imidazol-1-yl)benzene) has been obtained under hydrothermal conditions. The structure of complex 1 has been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectrum. The complex 1 shows a (3,8)-connected twofold interpenetrated three-dimensional (3D) tfz-d topology with the point symbol (4³)₂ (4⁶·6¹⁸·8⁴). The photoluminescence behavior of complex 1 was also discussed in paper.     

Synthesis and Characterization of Pure Phase Zn(II) and Cd(II) Oxide Nanoparticles via Thermal Decomposition of Four New Zn(II) and Cd(II) Coordination Polymers

Four new Zn(II) and Cd(II) coordination polymers, [Zn(2-AMP)₂(N₃)₂]_n (1), [Zn(2-AMP)₂(SCN)₂]_n (2), [Cd(2-AMP)(N₃)₂]_n (3) and [Cd(2-AMP)₂(SCN)₂]_n (4) {2-AMP: 2-Aminomethylpyridine}, have been synthesized and characterized by single crystal X-ray diffraction, IR spectroscopy and elemental analyses. The Zinc(II) oxide and Cadmium(II) oxide nano-particles have been synthesized from thermolysis of 1–4 at 600 °C under air atmosphere for 4 h. The ZnO and CdO nanoparticles were characterized by X-ray diffraction and scanning electron microscopy (SEM). SEM images show the average size of produced ZnO and CdO nanoparticles are 60–70 nm in all compounds.