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1.
The combination of N‐heterocyclic and multicarboxylate ligands is a good choice for the construction of metal–organic frameworks. In the title coordination polymer, poly[bis{μ2‐1‐[(1H‐benzimidazol‐2‐yl)methyl]‐1H‐tetrazole‐κ2N3:N4}(μ4‐butanedioato‐κ4O1:O1′:O4:O4′)(μ2‐butanedioato‐κ2O1:O4)dicadmium], [Cd(C4H4O4)(C9H8N6)]n, each CdII ion exhibits an irregular octahedral CdO4N2 coordination geometry and is coordinated by four O atoms from three carboxylate groups of three succinate (butanedioate) ligands and two N atoms from two 1‐[(1H‐benzimidazol‐2‐yl)methyl]‐1H‐tetrazole (bimt) ligands. CdII ions are connected by two kinds of crystallographically independent succinate ligands to generate a two‐dimensional layered structure with bimt ligands located on each side of the layer. Adjacent layers are further connected by hydrogen bonding, leading to a three‐dimensional supramolecular architecture in the solid state. Thermogravimetric analysis of the title polymer shows that it is stable up to 529 K and then loses weight from 529 to 918 K, corresponding to the decomposition of the bimt ligands and succinate groups. The polymer exhibits a strong fluorescence emission in the solid state at room temperature.  相似文献   

2.
Reaction of cadmium nitrate with diphenylphosphinic acid in dimethylformamide solvent yielded the one‐dimensional coordination polymer catena‐poly[[bis(dimethylformamide‐κO)cadmium(II)]‐bis(μ‐diphenylphosphinato‐κ2O:O′)], [Cd(C12H10O2P)2(C3H7NO)2]n, (I). Addition of 4,4′‐bipyridine to the synthesis afforded a two‐dimensional extended structure, poly[[(μ‐4,4′‐bipyridine‐κ2N:N′)bis(μ‐diphenylphosphinato‐κ2O:O′)cadmium(II)] dimethylformamide monosolvate], {[Cd(C12H10O2P)2(C10H8N2)]·C3H7NO}n, (II). In (II), the 4,4′‐bipyridine molecules link the CdII centers in the crystallographic a direction, while the phosphinate ligands link the CdII centers in the crystallographic b direction to complete a two‐dimensional sheet structure. Consideration of additional π–π interactions of the phenyl rings in (II) produces a three‐dimensional structure with channels that encapsulate dimethylformamide molecules as solvent of crystallization. Both compounds were characterized by single‐crystal X‐ray diffraction and FT–IR analysis.  相似文献   

3.
We present the study on the sample transfer characteristics of two different microfluidic interfaces for 2D‐CE . These interfaces were manufactured using two different microfabrication technologies: one was obtained via the classical photolithography—wet etching—anodic‐bonding process; and the other was obtained via the selective laser‐induced etching process. The comparison of the two interfaces, and an intact capillary as a reference, was made via the CE separation of amino acids (arginine and lysine) under different bulk flow conditions, with and without applying bias potential to the secondary channels. The influence on peak shapes, migration times, and repeatabiliy were evaluated.  相似文献   

4.
The title compound, poly[μ3‐bromido‐(pyridine‐3‐carboxylato‐κN)copper(I)], [CuBr(C6H5NO2)]n, is a novel coordination polymer based on a copper–bromide net and nicotinic acid ligands. The asymmetric unit contains one copper(I) ion, one bromide ligand and one nicotinic acid ligand, all on general positions. The CuI atom is tetrahedral and coordinated by three bridging Br atoms and the N atom from the nicotinic acid ligand. The Cu–Br units form alternating six‐membered chair‐patterned rings in net‐like layers. The attached nicotinic acid units point alternately up and down. The layers are assembled into a three‐dimensional network via intermolecular O—H...O and C—H...Br hydrogen‐bonding interactions.  相似文献   

5.
To take into account static correlation effects in the quasi‐two‐dimensional electron gas a screened Coulombic interaction between particles is studied. The Thomas–Fermi approximation is used and the potential screening appears as a function of the Wigner–Seitz density parameter rs and the effective width t of the system. With the self‐consistent field theory applied to the modified deformable jellium, the ground‐state energy per particle and the conditions for electron localization are obtained in terms of the interparticle distance and the screening parameter μ. A critical minimum characteristic width tc is obtained; below tc no long‐range order is obtained. For larger widths a stable localized state is predicted at finite densities. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 82: 269–276, 2001  相似文献   

6.
We report a novel crystalline supramolecular polybenzobisimidazole (SP‐PBBI) capable of providing a two‐dimensional polymer (2DSP‐PBBI) by liquid‐phase exfoliation. A regular arrangement of rigid rod‐like polybenzobisimidazole (PBBI) chains is achieved by interchain hydrogen bonding. Titration of 2DSP‐PBBI with cobalt chloride (CoCl2) using UV‐Vis spectroscopy demonstrates the presence of bidentate NO ligands on the PBBI backbone and NO–Co(II) complexation. Imaging analysis using atomic force microscopy (AFM) reveals the planar surface morphology of exfoliated 2DSP‐PBBI sheets with lateral dimensions of <1 μm and thickness of <30 nm. The size of the polymer crystal growth is tuned by employing condensation/precipitation polymerization under nonisothermal conditions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1095–1101  相似文献   

7.
Application of Tris‐N‐[Tris(hydroxymethyl)methyl]glycine gels for 2DE is hampered by formation of mixed CHAPS–SDS micelles resulting in typical swirling pattern in the low mass range, which makes reliable quantitative and qualitative gel evaluation impossible. Modification of 2DE strip equilibration procedure prevented the direct interaction between both detergents during equilibration process, thus substantially improving gel separation.  相似文献   

8.
Reaction of biotin {C10H16N2O3S, HL; systematic name: 5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoic acid} with silver acetate and a few drops of aqueous ammonia leads to the deprotonation of the carboxylic acid group and the formation of a neutral chiral two‐dimensional polymer network, poly[[{μ3‐5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}silver(I)] trihydrate], {[Ag(C10H15N2O3S)]·3H2O}n or {[Ag(L)]·3H2O}n, (I). Here, the AgI cations are pentacoordinate, coordinated by four biotin anions via two S atoms and a ureido O atom, and by two carboxylate O atoms of the same molecule. The reaction of biotin with silver salts of potentially coordinating anions, viz. nitrate and perchlorate, leads to the formation of the chiral one‐dimensional coordination polymers catena‐poly[[bis[nitratosilver(I)]‐bis{μ3‐5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}] monohydrate], {[Ag2(NO3)2(C10H16N2O3S)2]·H2O}n or {[Ag2(NO3)2(HL)2]·H2O}n, (II), and catena‐poly[bis[perchloratosilver(I)]‐bis{μ3‐5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}], [Ag2(ClO4)2(C10H16N2O3S)2]n or [Ag2(ClO4)2(HL)2]n, (III), respectively. In (II), the AgI cations are again pentacoordinated by three biotin molecules via two S atoms and a ureido O atom, and by two O atoms of a nitrate anion. In (I), (II) and (III), the AgI cations are bridged by an S atom and are coordinated by the ureido O atom and the O atoms of the anions. The reaction of biotin with silver salts of noncoordinating anions, viz. hexafluoridophosphate (PF6) and hexafluoridoantimonate (SbF6), gave the chiral double‐stranded helical structures catena‐poly[[silver(I)‐bis{μ2‐5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}] hexafluoridophosphate], {[Ag(C10H16N2O3S)2](PF6)}n or {[Ag(HL)2](PF6)}n, (IV), and catena‐poly[[[{5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}silver(I)]‐μ2‐{5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}] hexafluoridoantimonate], {[Ag(C10H16N2O3S)2](SbF6)}n or {[Ag(HL)2](SbF6)}n, (V), respectively. In (IV), the AgI cations have a tetrahedral coordination environment, coordinated by four biotin molecules via two S atoms, and by two carboxy O atoms of two different molecules. In (V), however, the AgI cations have a trigonal coordination environment, coordinated by three biotin molecules via two S atoms and one carboxy O atom. In (IV) and (V), neither the ureido O atom nor the F atoms of the anion are involved in coordination. Hence, the coordination environment of the AgI cations varies from AgS2O trigonal to AgS2O2 tetrahedral to AgS2O3 square‐pyramidal. The conformation of the valeric acid side chain varies from extended to twisted and this, together with the various anions present, has an influence on the solid‐state structures of the resulting compounds. The various O—H...O and N—H...O hydrogen bonds present result in the formation of chiral two‐ and three‐dimensional networks, which are further stabilized by C—H...X (X = O, F, S) interactions, and by N—H...F interactions for (IV) and (V). Biotin itself has a twisted valeric acid side chain which is involved in an intramolecular C—H...S hydrogen bond. The tetrahydrothiophene ring has an envelope conformation with the S atom as the flap. It is displaced from the mean plane of the four C atoms (plane B) by 0.8789 (6) Å, towards the ureido ring (plane A). Planes A and B are inclined to one another by 58.89 (14)°. In the crystal, molecules are linked via O—H...O and N—H...O hydrogen bonds, enclosing R22(8) loops, forming zigzag chains propagating along [001]. These chains are linked via N—H...O hydrogen bonds, and C—H...S and C—H...O interactions forming a three‐dimensional network. The absolute configurations of biotin and complexes (I), (II), (IV) and (V) were confirmed crystallographically by resonant scattering.  相似文献   

9.
In poly[[μ3‐2,2′‐(disulfanediyl)dibenzoato‐κ5O:O,O′:O′′,O′′′](1,10‐phenanthroline‐κ2N,N′)cadmium(II)], [Cd(C14H8O4S2)(C12H8N2)]n, the asymmetric unit contains one CdII cation, one 2,2′‐(disulfanediyl)dibenzoate anion (denoted dtdb2−) and one 1,10‐phenanthroline ligand (denoted phen). Each CdII centre is seven‐coordinated by five O atoms of bridging/chelating carboxylate groups from three dtdb2− ligands and by two N atoms from one phen ligand, forming a distorted pentagonal–bipyramidal geometry. The CdII cations are bridged by dtdb2− anions to give a two‐dimensional (4,4) layer. The layers are stacked to generate a three‐dimensional supramolecular architecture via a combination of aromatic C—H...π and π–π interactions. The thermogravimetric and luminescence properties of this compound were also investigated.  相似文献   

10.
A cadmium–thiocyanate complex, poly[[bis(nicotinic acid‐κN)di‐μ‐thiocyanato‐κ2N:S2S:N‐cadmium(II)] monohydrate], {[Cd(NCS)2(C6H5NO2)2]·H2O}n, was synthesized by the reaction of nicotinic acid, cadmium nitrate tetrahydrate and potassium thiocyanide in aqueous solution. In the crystal structure, each CdII cation is in a distorted octahedral coordination environment, coordinated by the N and S atoms of nicotinic acid and thiocyanate ligands. Neighbouring CdII cations are linked together by thiocyanate bridges to form a two‐dimensional network. Hydrogen‐bond interactions between the uncoordinated solvent water molecules and the organic ligands result in the formation of the three‐dimensional supramolecular network.  相似文献   

11.
As part of an exploration of new coordination polymers, a cadmium‐dicyanamide complex, namely poly[benzyltriethylammonium [tri‐μ‐dicyanamido‐κ6N 1:N5‐cadmium(II)]], {(C13H22N)[Cd(C2N3)3]}n , has been synthesized by the reaction of benzyltriethylammonium bromide, cadmium nitrate tetrahydrate and sodium dicyanamide in aqueous solution, and characterized by single‐crystal X‐ray diffraction at room temperature. In the crystal structure, each CdII cation is coordinated by six nitrile N atoms from six anionic dicyanamide (dca) ligands to furnish a slightly distorted octahedral geometry. Neighbouring CdII cations are linked by dicyanamide bridges to construct a two‐dimensional anionic layer coordination polymer. One amide N atom in the bridging dca ligand is disordered over two sites. The cations lie between the anionic frameworks and there are no hydrogen‐bond interactions between the cations and anions. The organic cations are not involved in the formation of the supramolecular network.  相似文献   

12.
An organic–inorganic hybrid compound, catena‐poly[bis(3H‐imidazol‐1‐ium) [[tetracyanido‐κ4C‐cobalt(III)]‐μ‐cyanido‐κ2C:N‐[diaqualithium(I)]‐μ‐cyanido‐κ2N:C]], {(C3H5N2)2[CoLi(CN)6(H2O)2]}n, was synthesized by the reaction of Li3[Co(CN)6] with imidazolium chloride in aqueous solution. The compound crystallizes in the monoclinic space group C2/c (data collected at 273 K). In the crystal structure, neighbouring [Co(CN)6]3− anionic units are linked by Li+ cations through the cyanide groups in a trans mode, forming a one‐dimensional zigzag chain structure extending along the c axis. A three‐dimensional supramolecular network is formed through hydrogen‐bonding interactions and is further stabilized by weak CN...π interactions between the cyanide groups and the imidazolium cations.  相似文献   

13.
In the coordination compound poly[diaqua(μ2‐4,4′‐bipyridine)(μ2‐4‐carboxylatocinnamato)nickel(II)], [Ni(C10H6O4)(C10H8N2)(H2O)2]n, both the 4‐carboxylatocinnamate and 4,4′‐bipyridine (4,4′‐bpy) ligands act as bidentate bridges, connecting the NiII centres in an octahedral coordination geometry into a two‐dimensional (4,4) layer. Each layer polycatenates two other identical layers, thus giving a rare 2D → 3D polycatenating network (2D and 3D are two‐ and three‐dimensional, respectively), with a mutually parallel arrangement of the layers. The chiral 4,4′‐bpy ligands link the NiII centres into chiral chains, thus introducing chirality into the layer and the resulting 3D network.  相似文献   

14.
Bisindoles (BIMs) were modulated as powerful N,N′ donor ligands for the copper‐catalyzed Sonogashira reaction. Ligand screening experiments on 11 BIM compounds found that 3,3′‐(4‐chlorophenyl)methylenebis(1‐methyl‐1H‐indole) (10%) efficiently accelerated CuCl (5%)‐catalyzed cross‐coupling of aryl iodides with terminal alkynes. A wide range of substituted aryl iodides and/or alkyl‐ and aryl‐substituted terminal alkynes were examined, leading to the corresponding coupling products with yields up to 99%. An efficient and scalable protocol for the synthesis of BIM ligands on a gram scale, with extremely low catalyst loading of o‐ClC6H4NH3+Cl?, was also developed with a reaction time of 20 min with yields up to 93%. This novel N,N′ ligand was air‐stable, easily available and highly modulated with low copper loading. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

15.
The title complex, poly[bis(μ6‐pyridine‐2,6‐dicarboxylato N‐oxide)nickel(II)disilver(I)], [Ag2Ni(C7H3NO5)2]n or [Ag2Ni(pydco)2]n (H2pydco = pyridine‐2,6‐dicarboxylic acid N‐oxide), has a two‐dimensional sheet structure. The two carboxylate groups adopt two coordination modes. The NiII ion displays a distorted octahedral geometry, bonded to two carboxylate O atoms of two different pydco ligands and four O donors from another two ligands, i.e. two carboxylate O atoms and two N‐oxide O atoms. The AgI ion adopts a tetrahedral coordination, linked by three O atoms of three different carboxylate groups and an N‐oxide O atom.  相似文献   

16.
When {2,2′‐[(2‐methyl‐2‐nitropropane‐1,3‐diyl)diimino]diacetato}copper(II), [Cu(C8H13N3O6)], (I), was crystallized from a binary mixture of methanol and water, a monoclinic two‐dimensional water‐ and methanol‐solvated metal–organic framework (MOF) structure, distinctly different from the known orthorhombic one‐dimensional coordination polymer of (I), was isolated, namely catena‐poly[[copper(II)‐μ3‐2,2′‐[(2‐methyl‐2‐nitropropane‐1,3‐diyl)diimino]diacetato] methanol 0.45‐solvate 0.55‐hydrate], {[Cu(C8H13N3O6)]·0.45CH3OH·0.55H2O}n, (II). The monoclinic structure of (II) comprises centrosymmetric dimers stabilized by a dative covalent Cu2O2 core and intramolecular N—H...O hydrogen bonds. Each dimer is linked to four neighbouring dimers via symmetry‐related (opposing) pairs of bridging carboxylate O atoms to generate a `diamondoid' net or two‐dimensional coordination network. Tight voids of 166 Å3 are located between these two‐dimensional MOF sheets and contain a mixture of water and methanol with fractional occupancies of 0.55 and 0.45, respectively. The two‐dimensional MOF sheets have nanometre‐scale spacings (11.2 Å) in the crystal structure. Hydrogen‐bonding between the methanol/water hydroxy groups and a Cu‐bound bridging carboxylate O atom apparently negates thermal desolvation of the structure below 358 K in an uncrushed crystal of (II).  相似文献   

17.
The proliferation of increasingly more sophisticated analytical separation systems, often incorporating increasingly more powerful detection techniques, such as high‐resolution mass spectrometry, causes an urgent need for highly efficient data‐analysis and optimization strategies. This is especially true for comprehensive two‐dimensional chromatography applied to the separation of very complex samples. In this contribution, the requirement for chemometric tools is explained and the latest developments in approaches for (pre‐)processing and analyzing data arising from one‐ and two‐dimensional chromatography systems are reviewed. The final part of this review focuses on the application of chemometrics for method development and optimization.  相似文献   

18.
A novel infinite one‐dimensional silver cylinder, namely poly[μ‐ethylenediamine‐μ5‐(2‐sulfanidylbenzoato)‐μ4‐(2‐sulfanidylbenzoato)‐tetrasilver(I)], [Ag4(C7H4O2S)2(C2H8N2)]n, has been synthesized by one‐pot reaction of equivalent molar silver nitrate and 2‐mercaptobenzoic acid (H2mba) in the presence of ethylenediamine (eda). One Ag atom is located in an AgS2NO four‐coordinated tetrahedral geometry, two other Ag atoms are in an AgS2O three‐coordinated T‐shaped geometry and the fourth Ag atom is in an AgSNO coordination environment. The two mba ligands show two different binding modes. The μ2N:N′‐eda ligand, acting as a bridge, combines with mba ligands to extend the AgI ions into a one‐dimensional silver cylinder incorporating abundant Ag...Ag interactions ranging from 2.9298 (11) to 3.2165 (13) Å. Interchain N—H...O hydrogen bonds extend the one‐dimensional cylinder into an undulating two‐dimensional sheet, which is further packed into a three‐dimensional supramolecular framework by van der Waals interactions; no π–π interactions were observed in the crystal structure.  相似文献   

19.
The three‐dimensional coordination polymer poly[[bis(μ3‐2‐aminoacetato)di‐μ‐aqua‐μ3‐(naphthalene‐1,5‐disulfonato)‐hexasilver(I)] dihydrate], {[Ag6(C10H6O6S2)(C2H4NO2)4(H2O)2]·2H2O}n, based on mixed naphthalene‐1,5‐disulfonate (L1) and 2‐aminoacetate (L2) ligands, contains two AgI centres (Ag1 and Ag4) in general positions, and another two (Ag2 and Ag3) on inversion centres. Ag1 is five‐coordinated by three O atoms from one L1 anion, one L2 anion and one water molecule, one N atom from one L2 anion and one AgI cation in a distorted trigonal–bipyramidal coordination geometry. Ag2 is surrounded by four O atoms from two L2 anions and two water molecules, and two AgI cations in a slightly octahedral coordination geometry. Ag3 is four‐coordinated by two O atoms from two L2 anions and two AgI cations in a slightly distorted square geometry, while Ag4 is also four‐coordinated by two O atoms from one L1 and one L2 ligand, one N atom from another L2 anion, and one AgI cation, exhibiting a distorted tetrahedral coordination geometry. In the crystal structure, there are two one‐dimensional chains nearly perpendicular to one another (interchain angle = 87.0°). The chains are connected by water molecules to give a two‐dimensional layer, and the layers are further bridged by L1 anions to generate a novel three‐dimensional framework. Moreover, hydrogen‐bonding interactions consolidate the network.  相似文献   

20.
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