Effect of pH/Auxiliary Ligand on the Structures of Coordination Compounds Based on a Novel Ligand 2,6-Bis(pyrazin-2-yl)pyridine-4-carboxylate

Four new coordination compounds, [Zn(bppc)_2(H_2O)_2]·3 H_2O(1), [Zn2(bppc)2(mbdc)(H_2O)4]·7 H_2O(2), [Zn(bppc)2(H_2O)2]n·n(m-Hbdc)·n(H_2O)(3), [Zn2(bppc)(btc)(H_2O)3]n·5 n H_2O(4)(Hbppc = 2,6-bis(pyrazin-2-yl)pyridine-4-carboxylate, H2(m-bdc) = 1,3-benzenedicarboxylic acid, H3 btc = 1,3,5-benzene-tricarboxylic acid), have been hydrothermally synthesized and structurally characterized. Compound 1 shows a mononuclear structure and 2 shows a dinuclear structure. Compound 3 is a one-dimensional chain structure, which is extended into a 3D supramolecular network by intermolecular hydrogen interactions. In 4, a 1D loop-like chain is connected by(btc)3-anions to generate a 2D layer structure. The structure differences of 1~4 show that the p H and aromatic acid as auxiliary ligand have important influence on the final structures.iAdditionally, the luminescent properties of 1~4 have been investigated with fluorescent spectra in the solid state, and 1~4 display a strong fluorescent emission at room temperature and have potential applications as fluorescent-emitting materials.     

Synthesis,Crystal Structure and Luminescent Property of a Ag(Ⅰ) Coordination Polymer with a 3D Sandwich-like Framework

A new coordination polymer,{[Ag_2(bpp)_2(H_2O)_2]·bpdc·3H_2O}_n,derived from the ligand biphenyl-4,4'-dicarboxylic acid(H_2bpdc),has been obtained through a hydrothermal technique(bpp = l,3-bis(4-pyridyl)propane).Its single-crystal structure has been characterized by single-crystal X-ray diffraction,powder XRD,FT-IR,TGA and elemental analysis techniques.The single-crystal X-ray diffraction reveals that complex 1 consists of 1D infinite[Ag(bpp)(H_2O)]_n~(n+)cationic chains,2D anionic layer constructed by bpdc anions and free water which provide charge compensation in the crystal structure.The 1D infinite[Ag(bpp)(H_2O)]_n~(n+) cationic chains and 2D anionic layer are further stacked in-ABAB- fashion through intermolecular H-bonding to form a 3D sandwich-like framework.In addition,the luminescent property of complex 1 in the solid state at room temperature was investigated.     

Three Complexes Based on Synthetic-condition Strategy Involving a Universal Mixed-ligand System

Three coordination polymers([Zn(H_2biim)_2(H_2O)_2]_2·2(HO-BDC)·x(H_2O)(1)[Cd(H_2biim)_2(H_2O)_2]_2·2(HO-BDC)·x(H_2O)(2) and [Co(HO-BDC)(bbi)]n(3)) are obtained by using synthetic-condition strategy in the mixed-ligand system 5-hydroxyisophthalic acid(OH-BDC)together with bisimidazole ligands(2,2?-biimidazole(H2 biim) and 1,1?-(1,4-butanediyl)bis(imidazole)(bbi)). The structure determination reveals that complexes 1 and 2 are zero-dimensional(0 D) structures, and complex 3 is a dinuclear two-dimensional(2D) layer structure. They are all 3D supramolecular networks. The comparisons of the synthetic-condition effects and structure differences among 1 ～3 and our previous work complexes 4([Co_2(HO-BDC)_2(bbi)_2]·H_2O) and 5([Zn(HO-BDC)(bbi)]) have been discussed in detail. Furthermore, the luminescent properties and thermal stabilities of compounds 1～3 in the solid state have been studied.     

A 3D Nickel(Ⅱ) Complex Constructed by Bis(2-dimethylaminoethyl) Ether: Solvothermal Synthesis,Crystal Structure and Catalytic Properties

Treatment of bis(2-dimethylaminoethyl) ether(BDMAE) with nickel acetate afforded a novel 3D nickel(Ⅱ) complex [Ni(BDMAE)(H_2O)_3·(CH_3COO)_2·(H_2O)_2] under solvothermal conditions. Its crystal structure was characterized by elemental analysis, IR spectrum, PXRD and single-crystal X-ray diffraction analysis. The complex belongs to the orthorhombic system, space group C2221 with a=8.823(2), b=13.932(3), c=17.563(4) ?, V=2158.9(8) ?~3, Z=4, C_(12)H_(36)N_2NiO_(10), Mr=427.14, Dc=1.314 g/cm~3, F(000)=920 and μ=0.944 mm~(-1). Single-crystal X-ray diffraction reveals that the mononuclear nickel(Ⅱ) ion is six-coordinated to one oxygen, two nitrogen atoms of the BDMAE ligand and three oxygen atoms of coordinated water molecules. The complex exhibits a 3D supramolecular structure through a variety of intermolecular and intramolecular hydrogen bonding interactions. In addition, the complex has been investigated for catalytic properties towards the Henry reaction of nitromethane with p-nitrobenzaldehyde, and the results indicated that the 1-p-nitrophenyl-2-nitroethanol product was obtained in excellent yield under optimum conditions with the complex as the catalyst.     

Synthesis,Characterization and Molecular Structure of a Diiron Complex(μ-SCH_2CH_2CH_2S-μ)Fe_2(CO)_5(Ph_2PCH_3)

The title complex,(μ-pdt)Fe_2(CO)_5(Ph_2PCH_3)(pdt = SCH_2CH_2CH_2S),was obtained by the reaction of the parent complex(μ-pdt)Fe_2(CO)_6 with Ph_2PCH_3 and Me_3NO·2H_2O in good yield(90%). The title complex was characterized by IR,~1H NMR,~(31)P{~1H} NMR and ~(13)C{~1H} NMR spectroscopy as well as by single-crystal X-ray diffraction analysis. The molecular structure shows that the title complex contains a butterfly diiron propanedithiolate cluster with five terminal carbonyls and a monophosphine ligand Ph_2PCH_3. The crystal packing diagram reveals that intermolecular C H···O hydrogen bonds between CH_2 and carbonyls,π-π stacking interactions and van der Waals' interactions stabilize the solid state to form a three-dimensional network.     

Four Complexes of Mn(Ⅱ), Co(Ⅱ), Ni(Ⅱ) and Cu(Ⅱ) Based on 2-Morpholine-4-yl-4,6-di-pyrazol-1-yl-1,3,5-triazine

Three azide bridged complexes, namely, [Mn_2L_2(N_3)_4(H_2O)_2](1), [Co_2L_2(N_3)_4]·(H_2O)_3(2) and [Ni_2L_2(N_3)_3(H_2O)]N_3·(H_2O)_4(3)(L = 2-morpholine-4-yl-4,6-di-pyrazol-1-yl-1,3,5-triazine), were synthesized by the reaction of L ligand, sodium azide with Mn(Ⅱ), Co(Ⅱ) and Ni(Ⅱ) chlorides. The copper(Ⅱ) chloride combined with thiocyanate and L ligand to form a mononuclear complex [CuL(CH_3OH)(SCN)(NCS)](4). Complexes 1~4 were characterized by IR, elemental analysis and X-ray crystallographic analysis. It was worth noting that two Mn(Ⅱ) atoms were connected by the end-to-end mode in 1, while Co(Ⅱ) and Ni(Ⅱ) atoms were connected by the end-on mode in 2 and 3. In complex 4, the central copper atom was coordinated with a sulfur atom and a nitrogen atom of the two thiocyanate ligands, respectively. Hydrogen bonds, π-π stacking interactions, thermogravimetric analysis and fluorescence properties of 1~4 were studied.     

Cobalt(Ⅱ) and Cadimium(Ⅱ) Metal-organic Frameworks Supported by a Multicarboxylate Ligand

Two metal-organic frameworks(MOFs) of formulae [Co_7(L)_3(4,4?-BPy)_2(OH)_2(H_2O)_6]·-4 H_2O(1) and [Cd_2(L)(2,2?-BPy)2]n(2, H_4L = 5-(3,5-dicarboxybenzyloxy)-isophthalic acid,2,2?-BPy = 2,2?-bipyridine, 4,4?-BPy = 4,4?-bipyridine) were synthesized under solvothermal conditions. The structures of 1 and 2 were characterized by X-ray single-crystal diffraction analysis.In complex 1, six cobalt atoms were connected by oxygen atoms to form a defect dicubane structure. The defect dicubane structures were further linked by Co(4,4?-BPy) units to generate a3-D network structure. Compound 2 displays a 2-D chain structure. The photoluminescent property of complex 2 is investigated. The results show the exclusive luminescence emission bands being originated from intraligand π-π* transitions.     

Two New Copper(Ⅱ) Complexes with p-Cyanobenzoic Acid: Synthesis,Crystal Structures and Properties

The complexes of [Cu(bpy)(H2O)(CBA)2]n 1 and [Cu(phen)(H2O)(CBA)2]·H2O 2 based on p-cyanobenzoic acid(HCBA) have been synthesized in aqueous ethanolic solution at room temperature. The single-crystal X-ray diffraction studies demonstrated that complex 1 crystallizes in orthorhombic and complex 2 is of triclinic system. The results indicate the complex 1 shows a 1D chain structure bridged by two carboxylic oxygen atoms from CBA–, and complex 2 is a mononuclear structure. Through intermolecular hydrogen bonding and π...π stacking interactions, the complexes are assembled into supramolecular structures. Complex 1 has been characterized by magnetic measurements. The magnetic measurement indicates that weak ferromagnetic interaction(zJ= 0.038(5)) between the Cu2+ ions is dominant in the structure. The IR spectrum and results of thermal and elemental analyses are also presented.     

Synthesis,Characterization and Electrochemistry of 1,2-Bis(diphenylphosphino)benzene-chelated Diiron Ethane-1,2-dithiolate Tetracarbonyl Complex

In this paper, a novel diiron ethane-1,2-dithiolate complex [Fe_2(CO)_4{κ~2-(Ph_2P)_2(1,2-C_6H_4)}(μ-SCH_2CH_2S)] has been prepared and structurally characterized. Treatment of the parent complex [Fe_2(CO)_6(μ-SCH_2CH_2S)] with 1 equivalent of 1,2-bis(diphenylphosphino)benzene and Me_3NO?2H_2O as the oxidative agent gave the title complex in good yield. The title complex has been characterized by elemental analysis, IR, ~1H NMR, ~(31)P{~1H} NMR, ~(13)C{~1H} NMR spectroscopy, and X-ray crystallography. X-ray crystal structure of the title complex contains a butterfly diiron cluster with a bridging ethane-1,2-dithiolate, four terminal carbonyls, and a chelating 1,2-bis(diphenylphosphino)benzene. In addition, electrochemical studies revealed that the title complex can catalyze the reduction of protons to H_2 in the presence of acetic acid.     

Synthesis,Structure and Fluorescent Property of a New Isolated Zn_6Co_9 Heteronuclear Cluster Constructed by Four Kinds of Ligands

A novel zero-dimensional heteronuclear cluster based on N-(phosphonomethyl)imino-diacetic acid(H4PMIDA) and Phen(1,10-phenanthroline), [Zn_6Co_9(PMIDA)_6(Phen)_6(NO_3)_4(H_2O)6]· 2NO_3·16H_2O, has been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectrum, thermal analysis, and single-crystal X-ray diffraction. The isolated 15-nuclearity cluster [Zn_6Co_9(PMIDA)_6(Phen)_6(NO_3)_4(H_2O)6]~(2+) was constructed by four kinds of ligands, and its charges are balanced by NO–3. Each isolated cluster is further extended into a 3D supramolecular network through π···π interaction and C–H···O hydrogen bonds. Moreover, the solid-state fluorescent property of this complex has also been investigated at room temperature.     

A Novel Three-dimensional Mn(Ⅱ) Coordination Polymer Constructed from Biphenyl-3,3?,5,5?-tetracarboxylic Acid and Water

The title Mn(Ⅱ) coordination polymer,poly{[heptaaqua-(μ4-bi-phenyl-3,3?,5,5?-tetracarboxylate)-bimanganese(Ⅱ)] pentahydrate},[Mn_2(bpta)(H_2O)_7]_n·5n H_2O(I),is crystallized from a mixture of biphenyl-3,3?,5,5?-tetracarboxylic acid(H_4bpta) and MnCl_2·4H_2O in waterethanol under room temperature. Its asymmetric unit consists of one and two halves of crystallographically independent Mn(Ⅱ) cations,one fully deprotonated H4 bpta ligand,seven coordinated water molecules and five solvent water as guest molecules. In I,each Mn(Ⅱ) atom is octahedrally coordinated by six oxygen atoms from bpta~(4-) anions and coordinated water molecules. In the Mn(Ⅱ) cations,one half Mn(Ⅱ) ion of them located at a 2-fold axis generating a trinuclear [Mn_3(H_2O)_2(RCOO)_2] linker by μ1,1-O(water) and μ1,3-O,O?(carboxylate) bridges and another half Mn(Ⅱ) ion with an inversion is a mononuclear linker. These neighbouring trinuclear and mononuclear Mn(Ⅱ) cations are linked together by biphenyl-3,3?,5,5?-tetracarboxylates to form a three-dimensional framework with a(42.84) topology of a(4,4)-connected net,in which the positions of the trinuclear [Mn_3(H_2O)_2(R-COO)_2] linker as a 4-connector linking four bpta~(4-) ligands in I reproduce an eagle-shaped arrangement. The polymeric structure exhibits a water channel with an accessible void of 797.1 ?~3,amounting to 15.7% of the total unit-cell volume. Each of the cavities in the network is occupied by solvent water molecules.     

Synthesis,Crystal Structure and Antitumor Activity of a Novel Zn(Ⅱ) Complex with 2-(Nicotinoyloxy)acetic Acid Ligand

A novel Zn(Ⅱ) complex, [ZnL_2(H_2O)_4]·H_2O(1, HL = 2-(nicotinoyloxy)acetic acid), was synthesized using Zn(OAc)_2·2H_2O and 2-(nicotinoyloxy)acetic acid as raw materials. Its structure has been elucidated by elemental analysis, IR and single-crystal X-ray diffraction. The structural analysis revealed that complex 1 crystallizes in triclinic, space group P1 and the Zn(Ⅱ) atom is six-coordinated with two N atoms from two different 2-(nicotinoyloxy)acetate anion ligands and four O atoms from coordinated water molecules. Complex 1 forms a 3D network structure by O–H···O hydrogen bonds. The antitumor activities of 2-(nicotinoyloxy)acetic acid ligand and its Zn(Ⅱ) complex were evaluated against human lung adenocarcinoma A549 cells, human hepatoma SMMC-7721 cells and human colon carcinoma Wi Dr cells.     

Synthesis,Structure and Characterization of a New Complex: [Mn(C_6H_(12)N_4)_2(H_2O)_4][Mn(H_2O)_6][SO_4]_2·6H_2O

A novel complex,[Mn(C_6H_(12)N_4)_2(H_2O)_4][Mn(H_2O)_6][SO_4]_2·6H_2O,was synthesized and hexagonal single crystals with centimeter-scale sizes were obtained by the method of solvent evaporation.It was characterized by elemental analysis,infrared spectrum,thermogravimetric analysis and X-ray single-crystal diffraction.The complex belongs to triclinic crystal system,space group P■ with a=9.3390(8),b=13.3520(13),c=16.3207(13)?,α=100.7160(3)°,β=90.1020(10)°,γ=109.9490(5)°,V=1874.9(3)?~3,Z=2,D_c=1.542 g/cm~3,M_r=870.64,μ=0.876 mm~(-1),T=293(2) K,F(000)=916 and S=0.990.The crystal structure determination displayed a distorted octahedral geometry around the manganese atom,which is bound to two nitrogen atoms from hexamethylenetetramine,acting as monodentate ligands,and to four aqua ligands.Variable-temperature magnetic measurements of the complex indicate the presence of weak antiferromagnetic interaction between manganese centers.     

A N-tripodal Ligand Cu-Based Coordination Polymer with Good Catalytic Activity for the Reduction of 4-Nitrophenol

A complex {[Cu(tib)_2(H_2O)_2]·(NO_3)_2}n(1) has been synthesized under N,N-dimethylacetamide(DMA) and water conditions. The structure of complex 1 was characterized by single-crystal X-ray crystallography. It crystallizes in monoclinic, space group P2_1/n with a = 10.6273(7), b = 11.4184(7), c = 13.4215(8) ?, β = 108.290(2)°, V = 1546.38(17) ?~3, Z = 2, F(000) = 798, D_c = 1.667 g/cm~3 and m = 0.786 mm~(-1). Complex 1 exhibits a 3D network due to the existence of O–H···O interaction between coordinated water and nitrate anions. Furthermore, complex 1 has a good catalytic activity for the reduction of 4-nitrophenol in Na BH4 solution.     

Synthesis,Crystal Structure and Fluorescent Properties of Silver and Cadmium Complexes

Two new complexes [Ag(bix)]n·n NAA·n H_2O(1) and [Cd(NAA)(phen)_2(H_2O)]2· 2CH_3COO-·H_2O(2)(bix = 1,4-bis(imidazol-1-ylmethyl)benzene,HNAA = α-naphthylacetic acid,phen = 1,10-phenanthroline) have been successfully synthesized under hydrothermal conditions.Their structures have been determined by elemental analyses,IR spectroscopy,TG and single-crystal X-ray diffraction analysis.The intermolecular hydrogen bonding or π-π stacking interactions extend the complexes into a 3D supramolecular structure.Moreover,the luminescent properties of complex 2 have been investigated in the solid state.     

Refinement of the Crystal Structure of Aconitine

The crystal of aconitine has been obtained through an unexpected spontaneous change of the solid power of aconitine in air and characterized by single-crystal X-ray diffraction analysis and elemental analysis. Crystallographic data: orthorhombic, space group P2_12_12_1 with a = 17.0745(6), b = 15.5990(6), c = 12.2443(6) ?, V = 3261.2(2) ?~3, Z = 4, C_(34)H_(47)NO_(11), M_r = 645.73, D_c = 1.315 g/cm~3, F(000) = 1384, μ(MoKa) = 0.098 mm~(-1), R = 0.0605 and wR = 0.1311. Aconitine is diester diterpenoid alkaloid, and its main structure is composed of four six-membered and two five-membered rings. The intramolecular and intermolecular O–H···O and C–H···O hydrogen bonds extend the adjacent molecules into a one-dimensional chain and a two-dimensional framework, which may be the essential reason for the change.     

Synthesis,Crystal Structure,Fluorescence, Thermal Stability and Magnetic Properties of the Dinuclear Manganese(Ⅱ) Complex [Mn_2(L)_2(2,2'-bipy)_2(H_2O)_5]_2·3H_2O

A new dinuclear manganese complex [Mn2(L)2(2,2'-bipy)2(H2O)5]2·3H2O has been synthesized with Mn SO4·H2O, 2,2'-bibenzoic acid(H2L) and 2,2'-bipyridine(2,2'-bipy) in the mixed solvent ethanol and water. It crystallizes in monoclinic, space group P1 with a = 9.9944(10), b = 21.939(2), c = 25.628(3) ?, α = 108.429(3), β = 100.613(4), γ = 102.821(3)o, V = 4997.9(9) ?3, Dc = 1.355 g/cm3, Z = 2, F(000) = 2108, GOOF = 1.074, the R = 0.0626 and w R = 0.1531. The structure of the complex contains two [Mn2(L)2(2,2'-bipy)2] units, ten coordinated H2 O molecules and three uncoordinated H2 O molecules. The fluorescence, thermal stability and magnetic properties of the complex were investigated.     

Syntheses,Structures, and Properties of Two Cobalt(Ⅱ) Coordination Complexes Based on(Fluorene-9,9-diyl) dipropanoic Acid and 1,3-Bis(imidazol-1-yl)butane Ligands

Two new cobalt(II) coordination complexes, namely [Co(HL)_2(biim)(H_2O)_2]_n·n H_2O(1) and [Co(Et L)_2(biim)]_n·3 n(H_2O)·2 n(Et HL)(2)(H_2L =(fluorene-9,9-diyl)dipropanoic acid, biim = 1,3-bis(imidazol-1-yl)butane), have been synthesized using the same starting reactants but different solvent medium. The two complexes exhibit distinctly different structures. Compound 1 exhibits a one-dimensional linear chain structure. However, complex 2 reveals a one-dimensional zigzag chain structure. Thermogravimetric analyses(TGA) and luminescent properties of these two complexes have been discussed.     

Syntheses and Structures of Three Hybrid Materials Using Vanadium Polyoxoanions and Macrocyclic Copper Complex as Building Blocks

The reactions of the four-coordinated macrocyclic copper complex [CuL](ClO_4)_2(L = 1,4,8,11-tetraazacyclotetradecane) with NH_4VO_3 under different conditions gave three inorganic-organic hybrid materials of [CuL][VO_3]_2·2.33H_2O(1), [CuL]_3[V_(10)O_(28)]·8H_2O(2) and [Cu L]3[V_6O_(18)]·8H_2O(3). Single-crystal X-ray diffraction analyses reveal that three diverse vanadium polyoxoanions, [V_6O_(18)]6- ring, [V_(10)O_(28)]6- cluster, and [V_(12)O_(35)]~(10-) ring, were isolated from the same reactant NH_4VO_3 under different conditions. The [CuL]~(2+) bridges the [V10O28]6- clusters to form a two-dimensional sheet in 2, and link the [V_6O_(18)]~(6-) rings in 1 and [V_(12)O_(35)]~(10-) rings in 3 into three-dimensional frameworks, respectively.     

Synthesis,crystal structure,magnetic properties and second harmonic generation of a new noncentrosymmetric coordination compound:Triaqua(4-amino-6-methoxypyrimidine) cuprate(Ⅱ)sulfate

The chemical preparation, crystal structure and infrared spectroscopic characterization of the triaqua(4-amino-6-methoxypyrimidine) cuprate(II) sulfate, [Cu(C_5H_7N_3)(H_2O)_3]SO_4, is reported. The compound crystallizes in the noncentrosymmetric orthorhombic space group P2_12_12_1 with lattice parameters a = 7.9025(3), b = 11.1189(4), c = 12.9720(4) , V = 1139.81(7) ~3 and Z = 4. The Cu(II) cation is fivecoordinated, in an early half-way between square pyramidal and trigonal bipyramidal fashion, by two nitrogen atoms of the 4-amino-6-methoxypyrimidine ligand and three water oxygen atoms. In the atomic arrangement, the organic ligands and the 5-connected Cu centers are linked with each other to give a 1-D corrugated hybrid chain running along the b-axis direction. The chains are interconnected by the SO_4~(2-) anions via O–H...O, O–H...S, C–H...O and N–H...O hydrogen bonds to form layers spreading parallel to the(011) plane. The vibrational absorption bands were identified by infrared spectroscopy. Quantitative measurements of the second harmonic generation(SHG) of a powdered sample at 1064 nm were performed and a relative efficiency of 5.2 times the KDP standard was observed. Magnetic properties were also defined to characterize the complex. Magnetic measurements revealed that this material had a onedimensional antiferromagnetic character. The magnetic parameters were g = 2.11 and 2J/k B = -36 K.