A Novel Gd Coordination Polymer Based on 2-(Pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate: Synthesis, Structure and Dielectric Properties

A new Gd coordination polymer based on 2-（pyridin-3-yl）-lH-imidazole-4,5-dicar- boxylate, formulated as {[Gd2（HPyIDC）2（H2O）5]·（bpy）·（NO3）2·3H2O}n （1, bpy = 4,4＇-bipyridine） has been synthesized under hydrothermal conditions. The compound crystallizes in triclinic, space group Pi with a = 11.451（2）, b = 11.596（2）, c = 15.7333（3） A, β = 79.47（3）°, Z = 2, V= 1948.6（7） A^3, C30H34Gd2N10O22, Dc = 2.047 g/cm^3, Mr= 1201.17, 2（MoKa） = 0.71073 A,μ = 3.477 mml, F（000） = 1176, the final R = 0.0554 and wR = 0.1181. Polymer 1 is a 2D network built up from 4-connected HPylDC2- anion and 4-connected Gd ions. Dielectric constant of complex 1 was measured at different frequencies with temperature variation.

A One-dimensional Cd(Ⅱ)Coordination Polymer Constructed from 1,4-Benzene-dicarboxylic Acid and 3-(2,6-Di(pyrazin-2-yl)pyridin-4-yl)-1H-indole:Synthesis,Structure and Photoluminescence

A new coordination polymer {[Cd（C_（21）H_（14）N_6）（C_8H_4O_4）]·H_2O}_n（1） was synthesized by an elaborate design via the reaction of 3-（2,6-di（pyrazin-2-yl）pyridin-4-yl）-1H-indole（bppi）,1,4-benzene-dicarboxylic acid（H2bdc） and cadmium（Ⅱ） nitrate in CH_3OH/H_2O mixed solvents. Complex 1 crystallizes in orthorhombic,space group Ccca with a = 20.012（4）,b = 31.881（6）,c = 19.808（4） ？,V = 12638（4） ？~3,Z = 16,C_（29）H_（20）CdN_6O_5,M_r = 644.91,D_c = 1.356 g·cm^（-3）,μ = 0.735 mm^（-1）,F（000） = 5184,GOOF = 1.046,the final R = 0.0405 and wR = 0.1063 for 6870 observed reflections（I 〉 2σ（I））. The Cd（Ⅱ） centre is hepta-coordinated by three N and four O atoms from one bppi terminal ligand and two bdc2– ligands,respectively,displaying a capped trigonal prism geometry. Structure extension gives coordination polymeric chains,in which the bdc2– linkers connect Cd（Ⅱ） cations into a one-dimensional（1D） coordination polymer along the c axis,giving zigzag chains with the Cd···Cd separation of 11.178（1） ？. The adjacent bppi terminal ligands in the chains are anti-periplanar conformation. The three-dimensional（3D） structure is stabilized by π···π stacking and hydrogen-bonding interactions to form a supramolecular self-penetrating network with 1D channels. In 1,there are voids 2999.7 ？~3 with 23.7% of per unit cell volume. Thermal analysis indicates that the framework of 1 is stable until 651 K and the photoluminescence of 1 in the solid shows very weak fluorescence at 382 and 560 nm upon excitation at 310 nm.

Synthesis,Crystal Structure and Biological Activity of 2-[(Pyridin-2-yl)methylthio]-1H-benzimidazole Derivatives

In order to discover the novel anti-tumor agents, a series of 2-[（pyridin-2-yl）methylthio]-1 H-benzimidazole derivatives were designed and synthesized, and the structures were characterized by IR, MS, and proton NMR. 2-[（3,4-Dimethoxypyridin-2-yl）methylthio]-1 Hbenzimidazole was investigated with X-ray crystallography, and the molecule is in orthorhombic system, space group P212121, with a = 9.1828（16）, b = 11.625（2）, c = 13.463（2） ？, Z = 4, R = 0.0231 and wR = 0.0596. The antitumor activities of target compounds were evaluated against human liver cancer cell line HepG2, and human liver normal cell line HL7702 using MTT assay. The target compounds have demonstrated weak or moderate anti-tumor activity against HepG2, while all the target compounds exhibit no cytotoxic effects on HL7702.

Synthesis, Structure and Photocatalytic Activity of Two 4-(2,6-Di(pyrazin-2-yl)pyridin-4-yl)benzoate-Based Chain Complexes

Two new one-dimensional chains extended by alternate benzenedicarboxylate（BDC） and 4-（2,6-di（pyrazin-2-yl）pyridin-4-yl）benzoate（L-） connectors, {[Cu（L）（BDC）（0.5）]·3.5 H2 O}n （1） and {[Zn（L）（BDC）（0.5）] ·H2 O}n （2）, were solvothermally synthesized. Complex 1 is in triclinic system, space group P1 with a = 9.6456（14）, b = 11.1160（16）, c = 12.0414（18） A, α = 106.266（3）, β = 92.277（3）, γ =108.104（3）°, V = 1166.6（3） A3, Dc = 1.603 g·cm（-3）, Mr = 563.00, Z = 2, F（000） = 578, μ = 0.996 mm（-1）, the final R = 0.0575 and wR = 0.1386 for 3704 observed reflections with I ＆gt; 2σ（I）. Complex 2 crystallizes in monoclinic, space group C2/c with a = 28.607（5）, b = 8.9767（16）, c = 19.705（4） ？, β = 125.396（3）°, V = 4125.0（13） ？3, Dc = 1.674 g·cm（-3）, Mr = 519.79, Z = 8, F（000） = 2120, μ = 1.242 mm（-1）, the final R = 0.0487 and w R = 0.0907 for 2944 observed reflections with I ＆gt; 2σ（I）. Resulting from the narrower band gap and broader response to visible light, the CuII-chain exhibits better photocatalytic performance towards the degradation of rhodamine B and methylene blue than those of ZnII-chain.

4-(7-Methoxy-2,2-dimethyl-2,3-dihydrobenzo-furan-5-yl)-N-(pyridin-2-yl)thiazol-2-amine: Chiral Crystal from Achiral Molecule

The title compound 4-（7-methoxy-2,2-dimethyl-2,3-dihydrobenzofuran-5-yl）-N- （pyridin-2-yl） thiazol-2-amine was synthesized by reacting 2-bromo-1-（7-methoxy-2,2-dime- thyl-2,3-dihydrobenzofuran-5-yl）ethanone with 1-（pyridine-2-yl）thiourea, and its crystal was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, chiral space group C2 with a = 18.1328（14）, b = 5.5969（5）, c = 19.2195（15） A, β= 115.5420（10）°, V= 1759.9（2）A3, Z = 4, F（000） = 744, C19H19N3O2S, Mr= 353.43, Dc= 1.334 g/cm3, S = 1.15, μ = 0.201 mm-1, the final R = 0.035 and wR = 0.111 for 2307 observed reflections （I 〉 2σ（I））. The Flack parameter is -0.03（10）. The preliminary bioassay result indicated that the title compound exhibits strong insecticidal activity （93.75% mortality） against Mythimna separate at the concentration of 1.000 g/L.

Crystal Structure,Thermal Behavior and Luminescence of a New Dimeric Manganese(Ⅱ) Complex Constructed with 3-Carboxy-1-carboxymethyl-2-oxidopyridinium

A new dimeric Mn（Ⅱ） complex,namely,[Mn（L）（PIP）]_2·H_2O（1）,was synthesized under hydrothermal condition（H_2L = 3-carboxy-1-carboxymethyl-2-oxidopyridinium and PIP = 2-（pyridin-3-yl）-1H-imidazo[4,5-f][1,10]phenanthroline）.It crystallizes in triclinic,space group P1 with a = 9.2037（13）,b = 9.6794（13）,c = 14.649（3） A,α = 94.858（3）,β = 94.928（3）,γ = 114.468（2）o,V = 1172.9（3） A^3,Z = 1,C_（52）H_（34）Mn_2N_（12）O_（11）,Mr = 1112.79,Dc = 1.575 g/cm^3,F（000） = 568,μ（Mo Ka） = 0.618 mm^-1,R = 0.0432 and w R = 0.1151.In 1,two L anions bridge two Mn（Ⅱ） atoms to give a dimeric [Mn（L）（PIP）] unit with the Mn···Mn distance of 3.009（2） A.The two PIP ligands are located on both sides of the dimer,which provides suitable π-π stacking interactions between PIP ligands.By these π-π stacking interactions,adjacent dimers are extended into a two-dimensional supramolecular layer.Further,the strong N–H···O hydrogen bond stabilizes the supramolecular layer structure of 1.Moreover,the thermal behavior and luminescent property of 1 have been studied.

A Y(Ⅲ)-organic Coordination Polymer Constructed from 2-(Pyridine-4-yl)-1H-imidazole-4,5-dicarboxylate and Oxalate Ligands: Structure and Luminescent Property

A novel compound, {[Y（HPIDC）（OX）1/2（H2O）]·2H2O}n （1, H3PIDC = 2-（pyridin-4- yl）-1H-imidazole-4,5-dicarboxylic acid, H2OX = oxalic acid）, has been synthesized under hydrothermal conditions and characterized by thermal analysis （TGA）, powder X-ray diffraction （PXRD）, and single-crystal X-ray diffraction. Complex 1 crystallizes in monoclinic space group P21/c with a = 8.342（8）, b = 14.61（1）, c = 11.487（1）, β = 90.78（9）°, V = 1400.4（2）3, Z = 4, C11H11N3O9Y, Mr = 418.14, Dc = 1.983 g/cm3, F（000） = 836, Rint = 0.0509, T = 293（2） K, μ = 4.240 mm-1, the final R = 0.0477 and wR = 0.1125 for 2770 observed reflections with I 2σ（I）. Compound 1 exhibits a 3D framework and generates the 1D open channels filled with free water molecules. The structure of 1 can be rationalized as a diamondoid network when the atom yttrium is regarded as a 4-connected node linking four surrounding yttrium atoms. The luminescent property of compound 1 is also investigated.

Multicomponent cascade reaction of 3-formylchromones:Highly regioselective synthesis of functionalized pyridin-2(1H)-ones

A novel protocol was developed for the construction of highly functionalized pyridin-2(1H)-ones from 3-formylchromones,ethyl 2-(pyridin-2-yl)acetate derivatives and amines via a complex multicomponent cascade reaction involving targeted duplicated ring-opening and duplicated cyclization reactions which form skeleton-reorganized target compounds.A series of pyridin-2(1H)-ones were produced by this reaction accompanied by the formation of three bonds(one C–N and two C–C bonds)and the cleavage of one bond in one step.This protocol can be used in combinatorial and parallel syntheses of various pyridin-2(1H)-ones with potent biological activity.The advantages of this approach include simple and practical operation(multicomponent one-pot),high yields(up to 91%),and products with potential biological activity.

Synthesis,structure and dielectric properties of a novel Gd coordination polymer based on 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarboxylate

A new Gd coordination polymer based on 2-（pyridin-4-yl）-I H-imidazole-4,5-dicarboxylate （H3PIDC） has been synthesized under hydrothermal conditions, formulated as {[Gd3（HPIDC）3（PIDC）（H2O）4].3H2O}n （1）. The compound crystallizes in the monoclinic system, space group C2/c with a=20.951（7）, b = 9.515（3）, c = 27.483（10） A,β= 106.176（6）°, Z = 4, V= 5262（3） A3, C40 H45 Gd3 N12 O30, Dc = 2.071 g/cm3, Mr=1645.63, λ （MoKa）=0.71073A, μ=3.846mm-1, F（000）=3204, the final R=0.0390 and wR= 0.1332. Complex 1 is a two-dimensional MOF built up from T-shaped 3-connected HPIDC2 , PIDC3 and 4-connected metal nodes. Dielectric constant of complex 1 was measured at different frequencies with temperature variation.

Auxiliary Ligand-tuned Structural Variation of Cd(Ⅱ)Coordination Polymers:Synthesis,Crystal Structures and Luminescent Properties

Two new Cd（Ⅱ） coordination polymers, [Cd（PT）（1,4-BDC）0.5]n （1） and [Cd（PT） （1,3-BDC）0.5]n （2） （HPT = 3-（pyridin-2-yl）-1,2,4-triazole, 1,4-H2BDC = 1,4-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid）, have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction as well as elemental analysis and IR. Complexes 1 and 2 are both three-dimensional coordination polymers with two-dimensional sheet structures bridged by the deprotonated carboxylate ligands. In 1, 1,4-BDC2- bridges the layered network to generate a quadrangular framework, and 2 owns a sexangular framework, which was caused by the different steric hindrance between 1,4-BDC^2- and 1,3-BDC^2-. Their thermal stabilities and photoluminescent properties have been also investigated.

Synthesis and properties of novel N,C,N terdentate skeleton based on 1,3-di(pyridin-2-yl)benzene moiety-new tricks for old dogs

Utilization of intermolecular Friedel-Crafts and intramolecular condensation reaction,novel 1,3-di-(pyridine-2-yl)benzene(N,C,N terdentate)skeleton with electro-withdrawing group in 6'position of pyridyl and a cyclization between 6'position of pyridyl and 6 position of benzyl ring were firstly designed and synthesized.The structures of these novel N,C,N terdentate were confirmed by NMR,MS and X-ray single crystalanalyses.The photophysical properties of these compounds were briefly explored.

Potential anti-tubercular agents:Hexahydro-3-phenyl indazol-2-yl(pyridin-4-yl)methanones from anti-tubercular drug isoniazid and bis(substituted-benzylidene)cycloalkanones

A series of indazol-2-yl（pyridin-4-yl）methanones, 4 were acquired from 2,6-bisbenzylidene cyclohex- anones, 3 and anti-tubercular drug （isoniazid）, and their anti-tubercular impacts were screened. Among the test compounds used against Mycobacterium tuberculosis H37 Ra cell line in the microplate alamar blue assay, the compounds 4g-j revealed moderate anti-tubercular activity with MIC 12.5 μg/mL, comparable to standard drugs （streptomycin, MIC, 6.25 μg/mL, pyrazinamide, isoniazid and ciprofloxacin with MICs of 3.125 μg/mL）.

On the road towards the global analysis of human synapses

Synapses are essential units for the flow of information in the brain.Over the last 70 years,synapses have been widely studied in multiple animal models including worms,fruit flies,and rodents.In comparison,the study of human synapses has evolved significantly slower,mainly because of technical limitations.However,three novel methods allowing the analysis of molecular,morphological,and functional properties of human synapses may expand our knowledge of the human brain.Here,we briefly describe these methods,and evaluate how the information provided by each unique approach may contribute to the functional and anatomical analysis of the synaptic component of human brain circuitries.In particular,using tissue from cryopreserved human brains,synaptic plasticity can be studied in isolated synaptosomes by fluorescence analysis of single-synapse long-term potentiation（FASS-LTP）,and subpopulations of synapses can be thoroughly assessed in the ribbons of brain tissue by array tomography（AT）.Currently,it is also possible to quantify synaptic density in the living human brain by positron emission tomography（PET）,using a novel synaptic radio-ligand.Overall,data provided by FASS-LTP,AT,and PET may significantly contribute to the global understanding of synaptic structure and function in both healthy and diseased human brains,thus directly impacting translational research.

New Ligands for Copper-Catalyzed C-N Coupling Reactions at Gentle Temperature

Pyridin-2-ol-N-oxide was designed as an efficient ligand for the coupling reaction of aryl iodides,aryl bromides and aryl chlorides,respectively,with primary amines,cyclic secondary amines or N-containing heterocycles at room or moderate temperature.The catalytic system showed great functional groups tolerance and excellent selective reactivity.