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1.
The Cu2+ ions in the title compounds, namely bis[1,3‐bis(pentafluorophenyl)propane‐1,3‐dionato‐κ2O,O′]copper(II) p‐xylene n‐solvate, [Cu(C15HF10O2)2nC8H10, with n = 1, (I), n = 2, (II), and n = 4, (III), are coordinated by two 1,3‐bis(pentafluorophenyl)propane‐1,3‐dionate ligands. The coordination complexes of (I) and (II) have crystallographic inversion symmetry at the Cu atom and the p‐xylene molecule in (I) also lies across an inversion centre. The p‐xylene molecules in (I) and (II) interact with the pentafluorophenyl groups of the complex via arene–perfluoroarene interactions. In the crystal of (III), two of the p‐xylene molecules interact with the pentafluorophenyl groups via arene–perfluoroarene interactions. The other two p‐xylene molecules are located on the CuO4 coordination plane, forming a uniform cavity produced by metal...π interactions.  相似文献   

2.
Mn(bzimpy)2(1)[bzimpy=2,6-bis(benzimidazol-2-yl)pyridine],a mononuclear manganese(Ⅱ)complex,was synthesized by the reaction of Mn(OOCMe)2 with bzimpy in absolute ethanol.The complex was structurally characterized by elemental analysis,cyclic voltammetry,and X-ray crystallography.In the complex,the manganese-nitrogen distances were different,and the geometry and the metal ion environment showed the distortion.The cyclic voltammetric measurements have been performed to assess its redox characteristics.The presence of oxidation wave at 0.62V and 0.081V vs.SCE or 0.8V and 1.0v vs.NHE suggested that this complex could catalyze the oxidation of water,therefore,simulate the water-oxidizing complex(WOC) of photosystem Ⅱ (PS Ⅱ).The measurements of photoreduction of 2,6-dichlorophenolindophenol (DCPIP),and oxygen evolution in the manganess-depleted and the comples 1-reconstituted PS Ⅱ preparations just support our conjecture.  相似文献   

3.
The crystal engineering of coordination polymers has aroused interest due to their structural versatility, unique properties and applications in different areas of science. The selection of appropriate ligands as building blocks is critical in order to afford a range of topologies. Alkali metal cations are known for their mainly ionic chemistry in aqueous media. Their coordination number varies depending on the size of the binding partners, and on the electrostatic interaction between the ligands and the metal ions. The two‐dimensional coordination polymer poly[tetra‐μ‐aqua‐[μ4‐4,4′‐(diazenediyl)bis(5‐oxo‐1H‐1,2,4‐triazolido)]disodium(I)], [Na2(C4H2N8O2)(H2O)4]n, (I), was synthesized from 4‐amino‐1H‐1,2,4‐triazol‐5(4H)‐one (ATO) and its single‐crystal structure determined. The mid‐point of the imino N=N bond of the 4,4′‐(diazenediyl)bis(5‐oxo‐1H‐1,2,4‐triazolide) (ZTO2−) ligand is located on an inversion centre. The asymmetric unit consists of one Na+ cation, half a bridging ZTO2− ligand and two bridging water ligands. Each Na+ cation is coordinated in a trigonal antiprismatic fashion by six O atoms, i.e. two from two ZTO2− ligands and the remaining four from bridging water ligands. The Na+ cation is located near a glide plane, thus the two bridging O atoms from the two coordinating ZTO2− ligands are on adjacent apices of the trigonal antiprism, rather than being in an anti configuration. All water and ZTO2− ligands act as bridging ligands between metal centres. Each Na+ metal centre is bridged to a neigbouring Na+ cation by two water molecules to give a one‐dimensional [Na(H2O)2]n chain. The organic ZTO2− ligand, an O atom of which also bridges the same pair of Na+ cations, then crosslinks these [Na(H2O)2]n chains to form two‐dimensional sheets. The two‐dimensional sheets are further connected by intermolecular hydrogen bonds, giving rise to a stabile hydrogen‐bonded network.  相似文献   

4.
The crystal structures of the title compounds, [Mo{(C4H8NO)2P(C2F5)}(CO)5], (1a), and [Mo{(C5H10N)2P(C2F5)}(CO)5], (2a), were determined as part of a larger project that focuses on the synthesis and coordination chemistry of phosphane ligands possessing moderate (electroneutral, i.e. neither electron‐rich nor electron‐deficient) electronic characteristics. Both complexes feature a slightly distorted octahedral geometry at the metal center, due to the electronic and steric repulsions between two of the four equatorial CO groups and the pentafluoroethyl group attached to the phosphane ligand. Bond length and angle data for (1a) and (2a) support the conclusion that the free phosphane ligands are electroneutral. For complex (1a), the Mo—P, Mo—Cax and Mo—Ceq(ave) bond lengths are 2.5063 (5), 2.018 (2) and 2.048 (2) Å, respectively, and for complex (2a) these values are 2.5274 (5), 2.009 (3) and 2.050 (3) Å, respectively. Geometric data for (1a) and (2a) are compared with similar data reported for analogous Mo(CO)5 complexes.  相似文献   

5.
Photocatalysis is a green technology for the treatment of all kinds of contaminants and has advantages over other treatment methods. Recently, much effort has been devoted to developing new photocatalytic materials based on metal–organic frameworks for use in the degradation of many kinds of organic contaminants. With the aim of searching for more effective photocatalysts, the title three‐dimensional coordination polymer, [Cd2(C8H4O4)2(C18H16N2O2)]n, was prepared. The asymmetric unit contains one CdII cation, one benzene‐1,2‐dicarboxylate anion (denoted L2−) and half of a centrosymmetric 1,4‐bis(pyridin‐3‐ylmethoxy)benzene ligand (denoted bpmb). Each CdII centre is five‐coordinated by four carboxylate O atoms from two L2− ligands and by one N atom from a bpmb ligand, forming a disordered pentagonal pyramidal coordination geometry. The CdII centres are interlinked by L2− ligands to form a one‐dimensional [Cd2L2]n chain. Adjacent chains are further connected by bpmb linkers, giving rise to a two‐dimensional network, and these networks are pillared by bpmb to afford a three‐dimensional framework with a 33.42.63.71.81 topology. Each grid in the framework has large channels which are filled mainly by the two other equivalent frameworks to form a threefold interpenetrating net. The compound exhibits relatively good photocatalytic activity towards the degradation of methylene blue in aqueous solution under UV irradiation.  相似文献   

6.
Three dinuclear copper(I) complexes, [Cu2(µ‐Cl)2(1,2‐(PPh2)2‐1,2‐C2B10H10)2]·2CH2Cl2 ( 1 ), [Cu2(µ‐Br)2(1,2‐(PPh2)2‐1,2‐C2B10H10)2]·2THF ( 2 ) and {Cu2(µ‐I)2[1,2‐(PPh2)2‐1,2‐C2B10H10]2} ( 3 ) have been synthesized by the reactions of CuX (X = Cl, Br and I) with the closo ligand 1,2‐(PPh2)2‐1,2‐C2B10H10. All these complexes were characterized by elemental analysis, FT‐IR, 1H and 13C NMR spectroscopy and X‐ray structure determination. Single crystal X‐ray structure determinations show that every complex contained di‐µ‐X‐bridged structure involving a crossed parallelogram plane formed by two Cu atoms and two X atoms (X = Cl, Br, I). The geometry at the Cu atom was a distorted tetrahedron, in which two positions were occupied by two P atoms of the PPh2 groups connected to the two C atoms of carborane (Cc), and the other two resulted from two X atoms which bridged the other Cu atom at the same time. To the best of our knowledge, this is the first example of copper(I) complexes with 1,2‐diphenylphosphino‐1,2‐dicarba‐closo‐dodecaborane as ligand characterized by X‐ray diffraction. The catalytic property of the complex 3 for the amination of iodobenzene with aniline was also investigated. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

7.
Two Ag(I) complexes, [Ag2(bobb)2]⋅(NO3)2 ( 1 ) and [Ag2(crotonate)2(aobb)]n ( 2 ) (bobb =1,3‐bis(1‐benzylbenzimidazol‐2‐yl)‐2‐oxapropane; aobb =1,3‐bis(1‐allylbenzimidazol‐2‐yl)‐2‐oxopropane), have been synthesized and characterized using elemental analysis, electrical conductivities, infrared and UV–visible spectral measurements and single‐crystal X‐ray diffraction. Complex 1 is binuclear and three‐coordinated by two N atoms from two bobb ligands, while complex 2 is a unique metal organic compound with diamond‐like multinuclear Ag centers with each Ag bridged by two aobb ligands and two crotonate ions to form one‐dimensional single polymer chain structures and extended into two‐dimensional frameworks through π–π and intermolecular C─H⋅⋅⋅O hydrogen bonds. The adjacent Ag(I) centers are bridged by allyl from aobb which is not only a σ‐bonding ligand, but also a π‐acid ligand. The DNA binding modes of complexes 1 and 2 were investigated using electronic absorption titration, fluorescence spectra and viscosity measurements. The results suggest that the two complexes bind to DNA via an intercalative mode, and their binding affinity for DNA follows the order 2  >  1 . This is due to the chelating effects which can enhance the planar functionality of the metal complexes.  相似文献   

8.
《Electroanalysis》2006,18(4):417-422
In dimethylformamide containing tetramethylammonium tetrafluoroborate, cyclic voltammograms for reduction of 4,4′‐(2,2,2‐trichloroethane‐1,1‐diyl)bis(chlorobenzene) (DDT) at a glassy carbon cathode exhibit five waves, whereas three waves are observed for the reduction of 4,4′‐(2,2‐dichloroethane‐1,1‐diyl)bis(chlorobenzene) (DDD). Bulk electrolyses of DDT and DDD afford 4,4′‐(ethene‐1,1‐diyl)bis(chlorobenzene) (DDNU) as principal product (67–94%), together with 4,4′‐(2‐chloroethene‐1,1‐diyl)bis(chlorobenzene) (DDMU), 1‐chloro‐4‐styrylbenzene, and traces of both 1,1‐diphenylethane and 4,4′‐(ethane‐1,1‐diyl)bis(chlorobenzene) (DDO). For electrolyses of DDT and DDD, the coulometric n values are essentially 4 and 2, respectively. When DDT is reduced in the presence of a large excess of D2O, the resulting DDNU and DDMU are almost fully deuterated, indicating that reductive cleavage of the carbon–chlorine bonds of DDT is a two‐electron process that involves carbanion intermediates. A mechanistic scheme is proposed to account for the formation of the various products.  相似文献   

9.
In catena‐poly[[aqua[1,3‐bis(pyridine‐3‐ylmethoxy)benzene‐κN]zinc(II)]‐μ2‐benzene‐1,4‐dicarboxylato‐κ2O1:O4], [Zn(C8H4O4)(C18H16N2O2)(H2O)]n, each ZnII centre is tetrahedrally coordinated by two O atoms of bridging carboxylate groups from two benzene‐1,4‐dicarboxylate anions (denoted L2−), one O atom from a water molecule and one N atom from a 1,3‐bis[(pyridin‐3‐yl)methoxy]benzene ligand (denoted bpmb). (Aqua)O—H...N hydrogen‐bonding interactions induce the formation of one‐dimensional helical [Zn(L)(bpmb)(H2O)]n chains which are interlinked through (aqua)O—H...O hydrogen‐bonding interactions, producing two‐dimensional corrugated sheets.  相似文献   

10.
The quasi‐living cationic copolymerization of 3,3‐bis(chloromethyl)oxetane (BCMO) and ε‐caprolactone (ε‐CL), using boron trifluoride etherate as catalyst and 1,4‐butanediol as coinitiator, was investigated in methylene chloride at 0°C. The resulting hydroxyl‐ended copolymers exhibit a narrow molecular weight polydispersity and a functionality of about 2. The reactivity ratios of BCMO (0.26) and ε‐CL (0.47), and the Tg of the copolymers, indicate their statistical character. The synthesis of poly(3,3‐bis(azidomethyl)oxetane‐co‐ε‐caprolactone) from poly(BCMO‐co‐ε‐CL) via the substitution of the chlorine atoms by azide groups, using sodium azide in DMSO at 110°C, occurs without any degradation, but the copolymers decompose at about 240°C. All polymers were characterized by vapor pressure osmometry or steric exclusion chromatography, 1H‐NMR and FTIR spectroscopies, and DSC. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1027–1039, 1999  相似文献   

11.
A novel diamine, 4,4‐bis(p‐aminophenoxymethyl)‐1‐cyclohexene (CHEDA), was synthesized from 4,4‐bis(hydroxymethyl)‐1‐cyclohexene and p‐chloronitrobenzene by nucleophilic aromatic substitution and subsequent catalytic reduction of the intermediate dinitro compound. A series of aromatic polyimides were prepared from CHEDA and commercial dianhydrides with varying flexibility and electronic character in two‐step direct polycondensation reactions. High molecular weight polyimides with intrinsic viscosities between 0.57 and 10.2 dL/g were obtained. Most of these polyimides, excluding those from PMDA and BPDA, were soluble in polar aprotic solvents such as NMP and DMAc, and many were also soluble in CHCl3 and THF. DSC analysis revealed glass transitions in the range of 190 to 250°C. No significant weight losses occurred below 450°C in nitrogen and 350°C in air. Bromination and epoxidation of cyclohexene double bond in CHDEA–6FDA (3e) were investigated as examples of possible polymer modifications. Qualitative epoxidation and selective bromination of the double bond were demonstated. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1189–1197, 1999  相似文献   

12.
Crystal and Molecular Structure of Bis(pyridine)bis(trifluoromethyl)zinc Bis(pyridin)bis(trifluoromethyl)zinc 1 has been isolated and characterized by means of single-crystal X-ray diffraction techniques. The title compound represents the first structure determination of a fully fluorinated alkylzinc compound (monoclinic, space group P21/c, Z = 4, a = 8.856(3), b = 18.158(3), c = 8.979(3) Å, β = 98.14(2)°, R = 0.054, Rw = 0.035). The zinc atom is in a distorted tetrahedral environment. The molecular structure of [ClZn(CCl2CF3) η2O]2 2 was solved, but is not included in a structural comparison due to crystallographic disorder.  相似文献   

13.
Many factors, such as temperature, solvent, the central metal atom and the type of coligands, may affect the nature of metal–organic frameworks (MOFs) and the framework formation in the self‐assembly process, which results in the complexity of these compounds and the uncertainty of their structures. Two new isomeric ZnII metal–organic frameworks (MOFs) based on mixed ligands, namely, poly[[μ‐1,5‐bis(2‐methyl‐1H‐imidazol‐1‐yl)pentane‐κ2N 3:N 3′](μ‐5‐methylisophthalato‐κ2O 1:O 3)zinc(II)], [Zn(C9H6O4)(C13H20N4)]n , (I), and poly[[μ‐1,5‐bis(2‐methyl‐1H‐imidazol‐1‐yl)pentane‐κ2N 3:N 3′](μ3‐5‐methylisophthalato‐κ3O 1:O 1′:O 3)(μ3‐5‐methylisophthalato‐κ4O 1:O 1′:O 3,O 3′)dizinc(II)], [Zn2(C9H6O4)2(C13H20N4)]n , (II), have been synthesized under hydrothermal conditions and characterized by single‐crystal X‐ray diffraction, IR spectroscopy, elemental analysis and thermogravimetric analysis. Complex (I) displays a two‐dimensional layer net, while complex (II) exhibits a twofold interpenetrating three‐dimensional framework. Both complexes show high stability and good fluorescence in the solid state at room temperature.  相似文献   

14.
New 1,4‐naphthyl and 2,6‐naphthyl‐containing polyarylates having inherent viscosities up to 1.28 dL/g were synthesized by the high‐temperature solution polycondensation from the acid chloride of 1,4‐bis(4‐carboxyphenoxy)naphthyl or 2,6‐bis(4‐carboxyphenoxy)naphthyl and various bisphenols. Most of the resulting polyarylates showed amorphous characteristics and were readily soluble in common organic solvents such as N,N‐dimethylacetamide (DMAc), N‐methyl‐2‐pyrrolidone (NMP), o‐chlorophenol, and chloroform. Transparent, flexible, and colorless films of these polymers could be cast from the DMAc solutions. Their cast films had tensile strengths ranging from 54.9 to 84.2 MPa, elongations at break from 5.3% to 19.0%, and initial modulus from 2.0 to 2.8 GPa. These polymers had glass transition temperatures in the range of 172–280°C and began to lose weight around 400°C, with 10% weight loss being recorded at about 450°C in air. Dynamic mechanical analysis (DMA) reveals that the polyarylates containing isopropylidene linkages have three transitions on the temperature scale between −100 and 300°C. However, only two transitions were observed in the other polyarylates without isoproylidene linkage. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 645–652, 1999  相似文献   

15.
The cadmium atom is coordinated in distorted pentagonal bipyramidal geometry by the pyridine‐nitrogen atom of the 4‐[N,N‐bis(2‐cyanoethyl)amino]pyridine ligand, two oxygen atoms of two methanol molecules and four oxygen atoms of two acetate groups. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

16.
The tin atom in (4‐Cl‐C6H4CH2)2Sn[S2CN(CH2CH2)2NCH3]2 is in a C2S4 skew‐trapezoidal bipyramidal geometry with the two carbon atoms being disposed over the weaker Sn? S bonds. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

17.
Assemblies of pyrazine‐2,3‐dicarboxylic acid and CdII in the presence of bis(1,2,4‐triazol‐1‐yl)butane or bis(1,2,4‐triazol‐1‐yl)ethane under ambient conditions yielded two new coordination polymers, namely poly[[tetraaqua[μ2‐1,4‐bis(1,2,4‐triazol‐1‐yl)butane‐κ2N4:N4′]bis(μ2‐pyrazine‐2,3‐dicarboxylato‐κ3N1,O2:O3)dicadmium(II)] dihydrate], {[Cd2(C6H2N2O4)2(C8H12N6)(H2O)4]·2H2O}n, (I), and poly[[diaqua[μ2‐1,2‐bis(1,2,4‐triazol‐1‐yl)ethane‐κ2N4:N4′]bis(μ3‐pyrazine‐2,3‐dicarboxylato‐κ4N1,O2:O3:O3′)dicadmium(II)] dihydrate], {[Cd2(C6H2N2O4)2(C6H8N6)(H2O)2]·2H2O}n, (II). Complex (I) displays an interesting two‐dimensional wave‐like structure and forms a distinct extended three‐dimensional supramolecular structure with the help of O—H...N and O—H...O hydrogen bonds. Complex (II) has a three‐dimensional framework structure in which hydrogen bonds of the O—H...N and O—H...O types are found.  相似文献   

18.
The kinetics of the polycondensation and copolycondensation reactions of bis(3‐hydroxypropyl) terephthalate (BHPT) and bis(4‐hydroxybutyl) terephthalate (BHBT) as monomers were investigated at 270 °C in the presence of titanium tetrabutoxide as a catalyst. BHPT was prepared by the ester interchange reaction of dimethyl terephthalate and 1,3‐propanediol (1,3‐PD). Through the same method adopted for BHPT synthesis, BHBT was prepared with 1,4‐butanediol instead of 1,3‐PD. With second‐order kinetics applied for polycondensation, the rate constants of the polycondensation of BHPT and BHBT, k11 and k22, were calculated to be 4.08 and 4.18 min?1, respectively. The rate constants of the cross reactions in the copolycondensation of BHPT and BHBT, k12 and k21, were calculated with results obtained from proton nuclear magnetic resonance spectroscopy analysis. The rate constants during the copolycondensation of BHPT and BHBT at 270 °C decreased in the order k12 > k22 > k11 > k21, indicating that the reactivity of BHBT was larger than that of BHPT at 270 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2435–2441, 2002  相似文献   

19.
In (C11H12N4)2ZnCl2, the zinc(II) center is coordinated by the pyridine nitrogen atoms of two 4‐[N,N‐bis(2‐cyanoethyl)amino]pyridine ligands and two chlorine atoms in a tetrahedral geometry. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

20.
A two‐dimensional MnII coordination polymer (CP), poly[bis[μ2‐2,6‐bis(imidazol‐1‐yl)pyridine‐κ2N3:N3′]bis(thiocyanato‐κN)manganese] [Mn(NCS)2(C11H9N5)2]n, (I), has been obtained by the self‐assembly reaction of Mn(ClO4)2·6H2O, NH4SCN and bent 2,6‐bis(imidazol‐1‐yl)pyridine (2,6‐bip). CP (I) was characterized by FT–IR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction. The crystal structure features a unique two‐dimensional (4,4) network with one‐dimensional channels. The luminescence and nitrobenzene‐sensing properties were explored in a DMF suspension, revealing that CP (I) shows a strong luminescence emission and is highly sensitive for nitrobenzene detection.  相似文献   

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