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1.
This article reports a simple self‐assembly process for facile one‐step synthesis of novel electromagnetic functionalized polypyrrole (PPy)/Fe3O4 composite nanotubes using p‐toluenesulfonic acid (p‐TSA) as the dopant and FeCl3 as the oxidant. The key trick of the present method is to use FeCl3 as the oxidant for both PPy and Fe3O4 in the same time to synthesize PPy/Fe3O4 composite nanotubes in one‐step. This facile one‐step method is much simpler than the conventional approach using the Fe3O4 nanoparticles as the additives. Compared to the similar composites synthesized using the conventional method, the as‐prepared PPy‐p‐TSA/Fe3O4 composite nanotubes using the facile one‐step self‐assembly process show much higher room‐temperature conductivity. Moreover, the composite nanotubes display interesting ferromagnetic behavior. The electrical properties of the PPy‐p‐TSA/Fe3O4 composite nanotubes are dominated by the amount of FeCl3 while their magnetic properties are controlled by the amount of FeCl2. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 320–326, 2010  相似文献   

2.
The fact that molecular crystals exist as different polymorphic modifications and the identification of as many polymorphs as possible are important considerations for the pharmaceutic industry. The molecule of N‐benzyl‐4‐hydroxy‐1‐methyl‐2,2‐dioxo‐1H‐2λ6,1‐benzothiazine‐3‐carboxamide, C17H16N2O4S, does not contain a stereogenic atom, but intramolecular hydrogen‐bonding interactions engender enantiomeric chiral conformations as a labile racemic mixture. The title compound crystallized in a solvent‐dependent single chiral conformation within one of two conformationally polymorphic P212121 orthorhombic chiral crystals (denoted forms A and B). Each of these pseudo‐enantiomorphic crystals contains one of two pseudo‐enantiomeric diastereomers. Form A was obtained from methylene chloride and form B can be crystallized from N,N‐dimethylformamide, ethanol, ethyl acetate or xylene. Pharmacological studies with solid–particulate suspensions have shown that crystalline form A exhibits an almost fourfold higher antinociceptive activity compared to form B.  相似文献   

3.
Two novel binuclear nickel(II) and cobalt(III) complexes with two or three dissimilar bridges, [Ni2(tacn)2(μ‐N3)2(μ‐O2CPh)](ClO4)?H2O ( 1 ) and [Co2(tacn)2(μ‐N3)(μ‐OH)(μ‐O2CPh)](ClO4)3 ( 2 ) (tacn=1,4,7‐triazacyclononane), were synthesized and structurally as well as magnetically characterized. Both compounds have a discrete binuclear structure, bridged by two N3? ions and one carboxylato group of the benzoate ion for 1 and one N3? ion, one carboxylato group of the benzoate ion, and one hydroxy group for 2 ; the macrocyclic ligand tacn acts as terminal ligand. The magnetic data of compound 1 were analyzed by means of ? = ?2J?1?2?D(?12+?22), leading to J = 19.6 cm?1, g=2.07, D = 4.01 cm?1, and zJ′ = 0.32 cm?1. The ferromagnetic interaction is discussed on the basis of the structural features.  相似文献   

4.
The structure of the title compound, {[Mg(C4H7O2)2(H2O)3]·H2O}n, features one‐dimensional ...(μ2‐ib)Mg(μ2‐ib)Mg... zigzag chains (ib is isobutyrate) parallel to the c axis. The octahedral Mg environment is completed by three fac‐oriented terminal water ligands, as well as one further monodentate end‐on coordinated ib ligand. In the crystal structure, the hydrophobic ib groups are all oriented within one half of the coordination perimeter of each chain, whereas the water ligands, together with hydrogen‐bonded noncoordinated solvent water molecules, define the other half. Along the a axis, neighbouring strands are oriented so that both the hydrophilic and hydrophobic sides are adjacent to each other. This results in an extensive hydrogen‐bonding network within the hydrophilic areas, also involving an additional solvent water molecule per formula unit. There are van der Waals contacts between the aliphatic isopropyl groups of the hydrophobic areas.  相似文献   

5.
The derivatives of pyrimidin‐4‐one can adopt either a 1H‐ or a 3H‐tautomeric form, which affects the hydrogen‐bonding interactions in cocrystals with compounds containing complementary functional groups. In order to study their tautomeric preferences, we crystallized 2,6‐diaminopyrimidin‐4‐one and 2‐amino‐6‐methylpyrimidin‐4‐one. During various crystallization attempts, four structures of 2,6‐diaminopyrimidin‐4‐one were obtained, namely solvent‐free 2,6‐diaminopyrimidin‐4‐one, C4H6N4O, (I), 2,6‐diaminopyrimidin‐4‐one–dimethylformamide–water (3/4/1), C4H6N4O·1.33C3H7NO·0.33H2O, (Ia), 2,6‐diaminopyrimidin‐4‐one dimethylacetamide monosolvate, C4H6N4O·C4H9NO, (Ib), and 2,6‐diaminopyrimidin‐4‐one–N‐methylpyrrolidin‐2‐one (3/2), C4H6N4O·1.5C5H9NO, (Ic). The 2,6‐diaminopyrimidin‐4‐one molecules exist only as 3H‐tautomers. They form ribbons characterized by R22(8) hydrogen‐bonding interactions, which are further connected to form three‐dimensional networks. An intermolecular N—H...N interaction between amine groups is observed only in (I). This might be the reason for the pyramidalization of the amine group. Crystallization experiments on 2‐amino‐6‐methylpyrimidin‐4‐one yielded two isostructural pseudopolymorphs, namely 2‐amino‐6‐methylpyrimidin‐4(3H)‐one–2‐amino‐6‐methylpyrimidin‐4(1H)‐one–dimethylacetamide (1/1/1), C5H7N3O·C5H7N3O·C4H9NO, (IIa), and 2‐amino‐6‐methylpyrimidin‐4(3H)‐one–2‐amino‐6‐methylpyrimidin‐4(1H)‐one–N‐methylpyrrolidin‐2‐one (1/1/1), C5H7N3O·C5H7N3O·C5H9NO, (IIb). In both structures, a 1:1 mixture of 1H‐ and 3H‐tautomers is present, which are linked by three hydrogen bonds similar to a Watson–Crick C–G base pair.  相似文献   

6.
The combination of the experimental (microcalorimetric and X-ray diffraction) methods and thermodynamic analyses enabled us to determine the phase diagram of the system hexacosane (n-C26H54)/octacosane (n-C28H58). Isothermal X-ray measurements performed on mixed samples at `low temperature' (T 308 K) revealed three crystalline forms: two monoclinic (M011 and Mdci) and one orthorhombic (Op). Four of the five rotator phases were observed at `high temperature': RI, RII, RIV, and RV. Fourteen solid-solid and two solid-liquid two-phase regions were observed, as well as one peritectic, one eutectoid, one metatectoid, and five peritectoid three-phase equilibria. The thermodynamic calculations of the phase-equilibrium relations, carried out with the polynomial functions described in a previous paper and new ones given here, showed full consistency with the experimental data, evidencing the reliability of these polynomial functions.  相似文献   

7.
 This second part of a systematic study of the properties of crosslinked-oriented gelatin involves the effects of orientation and water content on the glass transition temperature T g and on the melting behavior. The samples were the same as those in the preceding study, and their transition temperatures were determined by both differential scanning calorimetry and dynamic mechanical thermal analysis. The crosslinked gelatin which had been room-conditioned showed two transition temperatures: the lower one was attributed to T g of the water-plasticized gelatin, and the higher one was interpreted as T g of dried gelatin superimposed by melting. A rather unusual situation arose because of the fact that the T g and melting temperatures T m (217 and 230 °C, respectively) are so similar. Using water as plasticizer not only decreases T g but produces imperfect crystallites which melt below the T g of the system. The presence of the amorphous phase in the glassy state would presumably make it essentially impossible to define a melting point or crystallization temperature in the normal manner, as an equilibrium between crystalline and amorphous phases. Received: 8 October 1996 Accepted: 2 November 1995  相似文献   

8.
Two copper(II) complexes, [Cu(L)2](ClO4)2] and [Cu(L)(bipy)](ClO4)2, were prepared and characterized by the spectroscopic and analytic methods, where L is N-butylbenzimidazole and bipy is 2,2′-bipyridine. Single crystals of [Cu(L)(bipy)](ClO4)2 suitable for X-ray diffraction study were obtained by slow diffusion of diethyl ether into a DMF solution of the complex and the complex was found to crystallize as [Cu(L)(bipy)](ClO4)2·DMF. The asymmetric unit contains one [Cu(L)(bipy)]2+, two uncoordinated perchlorates, and one DMF solvate. Coordination geometry around Cu(II) is distorted square pyramidal with τ value of 0.31. Thermal properties of the complexes were examined by thermogravimetric analysis, indicating that the complexes are thermally stable to 310?°C. The metal complexes were screened for their in vitro antibacterial and antifungal activities Bacillus subtilis and Bacillus cereus (as Gram(+) bacteria), Escherichia coli, Enterobacter aerogenes, and Klebsiella pneumoniae (as Gram(–) bacteria), and Saccharomyces cerevisiae, Candida utilis, and Candida albicans (as yeasts). The complexes show antibacterial and antifungal activities against bacteria and yeasts.  相似文献   

9.
The title compound, C6H15N2+·C2H6NO4S2, crystallizes as a 0.11‐hydrate, (I), in the space group C2; the asymmetric unit consists of two cations (one of each enantiomer), one anion on a general position, two half anions, each with the N atom on a twofold axis, and approximately one fifth of a water molecule. The general anion departs significantly from the usual conformation: it lacks one of the typical `W'‐shaped sequence of O—S—N—S—O atoms. The compound also crystallizes in the solvent‐free form, (II), in the space group P21/c, with one formula unit in the asymmetric unit. Both compounds form ribbons of hydrogen‐bonded cation dimers parallel to the b axis. In (I), there are two independent ribbons of opposite chirality, each involving one anion on a special position, and these ribbons are connected by hydrogen bonds to the anion on a general position, resulting in a layer structure parallel to (100). In (II), the chains are connected by hydrogen bonds, and again a layer structure parallel to (100) results.  相似文献   

10.
The curing process of hexamethylene diisocyanate‐based polyurethane has been monitored by applying FTIR and DSC methods. A general relationship between glass‐transition temperature (Tg) and conversion of curing process has been obtained. This suggests that the reaction path and the relative reaction rates are independent of the curing temperature. The reaction kinetics of the system is analyzed using the Tg data converted to the conversion of the curing process. A set of experimental data and one theoretical model of Tg versus chemical conversion are presented to prove the assumption where a direct one‐to‐one relationship between the Tg (as measured) and the chemical conversion is obtained. Apparent activation energies (Ea) obtained by applying three different methods suggest good agreement. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2213–2220, 2000  相似文献   

11.
The title compound, C48H36N2S4, can be crystallized as two polymorphic structures, (I) and (II), both of which are in the triclinic space group P and possess Ci symmetry. In the crystal structure of polymorph (I), the adjacent naphthalene moieties are orientated towards one another and are inclined to one another by 78.7 (1)°, resulting in weak C—H⋯π interactions. In polymorph (II), the adjacent substituents are orientated away from one another, enclosing the pyrazine N atoms. In this way, the S atom of one substituent sits below the plane of the naphthalene ring of the other substituent.  相似文献   

12.
Molecular Aggregates of Donorsolvent-Free Lithiumsilylphosphanides with the Triphenylsilyl- and Triisopropylsilyl-Substituent at Phosphorus The lithiumphosphanides 6 and 7 were formed by lithiation of the bulky disilylphosphanes 1 a and 1 b with nBuLi in toluene as solvent. 1 a and 1 b are accessible in high yield by simple salt-elimination reactions, following a one-pot procedure. X-ray crystal structure determinations revealed that 6 exists as an donorsolvent-free dimer, whereas, surprisingly, 7 is a mixed tetrameric aggregate bearing three molecules LiP(SiiPr3)2 and one molecule LiPH(SiiPr3). The aggregate building block LiPH(SiiPr3) is obviously formed upon a nucleophilic Si? P bond cleavage in 1 b under the reaction conditions used for the lithiation. The tetramer 7 shows a unprecedented structure of a lithiumphosphanide: The lithium atoms are twofold-coordinated and exhibit extremely large endocyclic angles (153.4–164.5°). Furthermore the P4Li4 heterocyclooctane framework ist strongly flattened and the bulky silyl groups obviously suppress a rearrangement to a normal ladder-like structure. The flattened pyramidal coordination of the P atom, which bears one SiiPr3 group and one H atom, is probably due to steric effects.  相似文献   

13.
To further investigate the relationship between the structures of benzotriazol‐1‐yl‐based pyridyl ligands and their complexes, a new linear one‐dimensional HgII coordination polymer, [HgCl2(C12H10N4)]n, with the 1‐(2‐pyridylmethyl)‐1H‐benzotriazole (L) ligand was obtained through the reaction of L with HgCl2. In this complex, each HgII center within the one‐dimensional chain is coordinated by two chloride anions as well as by one pyridine and one benzotriazole N‐atom donor of two distinct L ligands in a distorted tetrahedral geometry, forming a linear one‐dimensional chain running along the [010] direction. Weak C—H...π and π–π stacking interactions link the one‐dimensional motifs to generate an overall two‐dimensional network parallel to the (100) plane. Comparison of the structural differences with previous findings suggests that the presence of different metal centers may plays an important role in the construction of such supramolecular frameworks.  相似文献   

14.
Crystal Structures of Acid Hydrates and Oxonium Salts. 36 [1]. Selenic Acid Tetrahydrate. Ionic as (H5O2)2SeO4 in an Orthorhombic as well as a Tetragonal Form Low-melting selenic acid tetrahydrate has been studied for the first time by crystal structure analysis. Two forms have been observed, an orthorhombic one with space group Pnma and Z = 4 and a tetragonal one with space group P4 21c and Z = 2. The lattice parameters at ?150°C are a = 6.130(3), b = 12.776(6) and c = 9.299(5) Å for the orthorhombic and a = 7.676(4) and c = 6.378(3) Å for the tetragonal form. Both forms are oxonium salts, corresponding to (H5O2)2SeO4. The ions are hydrogen-bonded into a three-dimensional array. The bonds within the diaquahydrogen cations have O ?O distances of 2.422(5) and 2.425(4) Å. The tetragonal form is isotypic to the tetrahydrate of sulfuric acid.  相似文献   

15.
The synthesis of some fluorescent 2,6‐dicyano‐3,5‐disubstituted anilines using cellulose sulfuric acid (Cellulose‐SA) as an environmentally benign catalyst in H2O is described. The one‐pot reaction of 1,3‐diketone and three equiv. of malononitrile was carried out in the presence of one equiv. of a secondary amine, Cellulose‐SA as catalyst, and H2O as solvent. The photophysical properties (λAbs., λFlu.) of the synthesized compounds in CH2Cl2, MeCN, and MeOH have been measured. The emission spectra of the new compounds in the solid state are also reported.  相似文献   

16.
The asymmetric unit of the title compound, poly[{μ4‐4‐[(carboxylatomethyl)sulfanyl]benzoato}(N,N‐dimethylformamide)zinc], [Zn(C9H6O4S)(C3H7NO)]n, consists of one crystallographically independent ZnII cation, one 4‐[(carboxylatomethyl)sulfanyl]benzoate (L2−) ligand and one coordinated dimethylformamide (DMF) molecule. The zinc ion is coordinated by five O atoms from four separate L2− ligands and one DMF molecule, and the ZnO5 unit displays a distorted square‐based‐pyramidal geometry. Two ZnO5 units form a binuclear zinc–tetracarboxylate paddlewheel cluster, and these are bridged by L2− ligands to generate an intersecting helical chain (Zn2+ ions as nodes), which is composed of right‐handed (P) and left‐handed (M) helices. Weak C—H...O hydrogen bonds extend the one‐dimensional coordinated chain into a weakly bound three‐dimensional supramolecular architecture.  相似文献   

17.
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   

18.
Salts of 3d, 4d, and 5d metals in the presence of the ligands 1,1,1,-tris(diphenylphosphinomethyl)ethane (triphos) or tris (2-diphenylphosphinoethyl) amine (np3) react with white phosphorus P4 (or yellow As4) to produce several mononuclear sandwich and dinuclear triple-decker sandwich complexes, which contain the unprecedented cyclo-triphosphorus (or cyclo-triarsenic) unit acting as a trihapto-ligand. In these complexes the metal atoms are bonded to the there phosphorus atoms of the phosphane ligand and to the three atoms of the cyclo-P3 or cyclo-As3 unit. The complexes are diamagnetic or have μeff-values corresponding to one or two unpaired electrons. The cyclo-P3 ligand is coordinatively unsaturated as proved by the fact that the mononuclear sandwich compounds may form Lewis-base adducts with electron-acceptor fragments. Reaction of the complexes (np)3M (M = Ni, Pd) with white P4 leads to formation of diamagnetic compounds [(np3)M(η1-P4)], in which the metal atom is bonded to the three phosphorus atoms of the np3-ligand and in addition to one P atom of the intact P4 molecule, which behaves as a monohapto-ligand. This article contains a review of the syntheses and structures of these complexes as well as a unified, albeit qualitative, approach to their bonding and properties.  相似文献   

19.
The question of whether or not fluorine substitution produces charge alternation is examined for CH4 and CH3F. Two sets of ab initio LCAO SCF MO wavefunctions (one a 3 G STO based one, the other a double zeta based one) are analyzed via charge density, localized CH bond moment, and population analysis calculations. Although both sets of wavefunctions show a slightly more negative H region in CH3F relative to CH4, in qualitative agreement with earlier work by Pople et al., the differences are small, and their sources are not clear. For example, in the 3 G calculations the CH localized orbital is the essential source of the increased density in CH3F, while for the double zeta calculations the increased density is due to the tail of an F lone-pair orbital trans to the CH bond. Consideration of details of these studies as well as those from large STO based SCF MO wavefunctions by Arrighini et al., suggests that one will need very accurate wavefunctions to resolve the problem unambiguously.The Radiation Laboratory is operated under contract with the U.S. Atomic Energy Commission. This is AEC document no. COO-38-847.  相似文献   

20.
Tetrameric [{RZn(NHNMe2)}4] (R = Me, Et), the first organometallic zinc hydrazides to be described, have been prepared by alkane elimination from dialkylzinc solutions and N,N‐dimethylhydrazine. They were characterised by 1H and 13C NMR and IR spectroscopy, mass spectrometry, elemental analysis and X‐ray crystallography. The compounds form asymmetric aggregates containing the novel Zn4N8 core; tetrahedra of Zn atoms bear the alkyl groups at Zn, with the triangular faces bridged by NHNMe2 substituents. The NH groups are connected to two Zn atoms, and the NMe2 groups to one. Hydrolysis of the compounds with water gives [(RZn)4(OH)(NHNMe2)3] as products, which also were characterised as described above. Higher yields of these hydroxo clusters were achieved in one‐pot syntheses by reaction of dialkylzinc solutions with mixtures of N,N‐dimethylhydrazine and water. They contain Zn4N6O cages, in which one hydroxide in the tetrameric hydrazides described above replaces one NHNMe2 group. Similar products can be prepared with alkoxy instead of hydroxy groups, in analogous one‐pot syntheses with alcohols. Alcoholysis of [EtZn(NHNMe2)]4 with methanol or ethanol gave zinc trishydrazide monoalkoxides, [(EtZn)4(OR)(NHNMe2)3] (R = Me, Et), which have constitutions analogous to the monohydroxides. The organozinc bishydrazide bisalkoxides [(MeZn)4(NHNMe2)2(OEt)2] and [(EtZn)4(NHNMe2)2(OEt)2] were obtained in one‐pot reactions from dialkylzinc solutions with mixtures of the hydrazine and alcohol, and their crystal structures, confirmed by spectroscopic methods in solution, show an unsymmetrical aggregation with the novel Zn4N4O2 cage structure.  相似文献   

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