共查询到20条相似文献,搜索用时 31 毫秒
1.
Yôichi Iida 《Molecular Crystals and Liquid Crystals》2013,570(3-4):195-198
Abstract Much attention has been paid to the solid anion radical salts of 7,7,8,8-tetracyanoquinodimethane (TCNQ), because of their prominent electronic properties.1–4 In particular, the salts containing mixed cations represented by [(C6H5)3PCH3]+ 1–x [(C6H5)3AsCH3]+ × (TCNQ)? 2, (0 ≤×≤ 1), are known to undergo phase transitions at 1 atm pressure in the solid state.1–4 The phase transition of pure methyltriphenylphosphonium salt, (x = 0.00), takes place at 315.7 K. Heat-capacity measurements of this phase transition have been made by Kosaki et al. 3 The transition has thus been found to be of the first order. The enthalpy and the total entropy change associated with the phase transition were experimentally determined to be 485.18 cal/mol and 1.7206 cal/deg.mol, respectively. For the solid solutions, it was found that the transition temperature (Tc ) is increased, while the magnitude of the heat of transition (δH) is decreased, progressively with an increase in the composition parameter (x) and that pure methyltriphenylarsonium salt, (x = 1.00), has no such phase transition up to the decomposition temperature of about 480 K at 1 atm pressure.1–3 Figure 1 shows the experimental relation between T c and x, together with the relation between δH and x.4 In the present paper, we attempted to explain thermodynamically the phase diagram of Figure 1 for the solid solutions of those TCNQ anion radical salts. 相似文献
2.
Single crystals of tetraethylammonium tetrachlorocuprate (II), [N(C2H5)4]2CuCl4, were grown by slow evaporation method at room temperature. The crystals were characterized through powder XRD, thermogravimetric (TG‐DTA), low temperature differential scanning calorimetric (DSC) studies and FTIR spectroscopy. While the powder XRD pattern of the compound shows sharp Bragg peaks confirming the crystallinity of the compound, the TG‐DTA studies confirm formation of the compound in the stoichiometric ratio. The thermal anomalies observed in DSC curve at ‐120°C in the heating cycle and around ‐30°C in the cooling cycle indicate a first order phase transition. The phase transition was predicted to be associated with the ordering of CuCl42‐ and successive long range orientation of [N(C2H5)4]+ ions which are disordered at high temperatures. The cationic [N(C2H5)4]+ plays a role in phase transitions at low temperatures. The sharp exothermic peak observed in high temperature DSC indicates a structural phase transition when [N(C2H5)4]CuCl3 is formed on heating the compound. The FTIR spectra of the compound characterize the various chemical bonding and water molecules adsorbed in the compound. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
3.
The N‐N dimethyl benzylammonium tetrachlorothallate (III) [C6H5CH2NH(CH3)2]TlCl4 crystallizes in the monoclinic system P21/n at room temperature with the following unit cell dimensions: a = 7.725(3) Å, b = 14.080(5) Å, c = 13.697(4) Å, β = 91.2(2)° with Z = 4. The structure shows a layer arrangement perpendicular to the b axis: planes of [TlCl4]‐ tetrahedra alternate with planes of [C6H5CH2NH(CH3)2]+ cations. The cohesion of the atomic arrangement is ensured by hydrogen bonds N‐H…Cl. Differential scanning calorimetric and optical birefringence measurements reveals a phase transition at T = 339K. Raman spectroscopic study and dielectric measurements were performed to discuss the mechanism of the phase transition. (© 2007 WILEY ‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
4.
Bo Keun Park 《Molecular Crystals and Liquid Crystals》2014,600(1):35-38
A novel C60-Os3 (carbon-metal) compound with long alkyl chain, Os3(CO)8[(C16H33O)3C6H2NC](μ3-η2:η2:η2-C60) (2), was synthesized by substituted reaction between one CO of Os3(CO)9(μ3-η2:η2:η2-C60) and (C16H33O)3C6H2NC (1). Compound 1 and 2 have been characterized by IR and 1H NMR. Cyclic voltammetry (CV) and differential scanning calorimetry (DSC) were performed to electrochemical property and phase transition of 2. 相似文献
5.
M. K. Kabir S. Kawata K. Adachi H. Tobita N. Miyazaki H. Kumagai 《Molecular Crystals and Liquid Crystals》2013,570(2):491-496
Abstract Hydrogen bond supported new iron-chloranilate assemblies, {(Hpy)[Fe(CA)2(H2O)2](H2O)}n (py = pyridine, H2CA = chloranilic acid, C6H2O4Cl2) (1), and [(phz)2[Fe(CA)2(H2O)2](H2O)2]n (phz = phenazine, C12H8N2) (2) have been synthesized and characterized. Compound 2 crystallizes in the monoclinic, space group C2/m (#12), with a= 29.135(6) Å, b= 16.886(6) Å, c = 15.017(5) Å, ß = 165.907(1)°, V= 1798(2) Å3, Z = 2. In both the compounds two chloranilate dianions and two water molecules are coordinated to the iron ion making anionic monomers [Fe(CA)2(H2O)2]?, which are the building blocks of the compounds. The coordination environment around the iron ion in the building block is a distorted octahedron, where two water molecules sit on the trans position to each other. [Fe(CA)2(H2O)2]? anions form common layer structures, supported by hydrogen bonds. Hpy+ are intercalated in between the layers of 1 by electrostatic and hydrogen bonding interactions and phz are intercalated in that of 2 by electrostatic interactions. DSC traces of 1 show anomaly at 174 K, indicating phase transition in the compound. 相似文献
6.
José A. García-Vázquez Jaime Romero Antonio Sousa-Pedrares Antonio Sousa A.D. Garnovskii Dimitri A. Garnovskii 《Journal of chemical crystallography》2000,30(1):23-26
The compound [Fe(C4H6N2)6][C5H4NSO3]2 crystallized in the monoclinic space group, P21/n with unit cell parameters: a = 13.676(3), b = 8.345(2), c = 18.663(4) Å, = 106.40(3)° and Z = 2. The title compound consists of a [Fe(C4H6N2)6]+2 hexacoordinated iron(II) cation and two C5H4NSO–
3 anions. In the cation the iron atom is coordinated to six N-methylimidazole imine nitrogen atoms in a distorted octahedral arrangement. The N1,N5,N1i,N5i atoms are coplanar and the iron lies in this plane. 相似文献
7.
Jerry L. Atwood Simon G. Bott Kerry D. Robinson Elizabeth J. Bishop Michael T. May 《Journal of chemical crystallography》1991,21(4):459-462
The title compound was synthesized by the reaction of [H3O+·18-crown-6][Cl-H-Cl–]·3.8 C6H5Me with two equivalents of H2O. Colorless crystals, which slowly deposited from the corresponding liquid clathrate, belong to the monoclinic space group P21/n witha=10.648(6),b=9.571(2),c=20.801(6) Å,=98.67(5)°, andD
c=1.24 g cm–3 forZ=4. Refinement based on 1609 observed reflections led to a finalR value of 0.072. In the crystal structure the [H3O+·18-crown-6]+ cations are packed in layers separated by puckered sheets of [(H5O
2
+
)(Cl–)2]–. 相似文献
8.
Monia Hamdouni Lamya Agengui Siwar Walha Ahlem Kabadou Abdelhamid Ben Salah 《Journal of chemical crystallography》2011,41(11):1742-1750
Abstract
In the present study we report the synthesis, crystal structure, spectroscopic and thermal analysis of mixed alkali A1−x (NH4) x (H2C2O4)(HC2O4)(H2O)2 with A = K, Rb. Single crystal refinements showed that the two compounds Rb0.86(NH4)0.14(H2C2O4)(HC2O4)(H2O)2 and K0.53(NH4)0.47(H2C2O4)(HC2O4)(H2O)2 adopt P − 1 space group. The nine fold coordination cationic sites are randomly occupied by Rb+/NH4 + and K+/NH4 + respectively for rubidium and potassium compounds. The structure consists of a three-dimensional network formed by the succession along (c) axis of corrugated sheets formed by alkali polyhedra layers in the packing of four-membered rings [A4(HC2O4)2(H2C2O4)2] linked and bridged by oxalate groups that behave as bi and tetradentate ligand under three different coordination modes. The stability of the crystal lattice is ensured by interesting hydrogen bonding contacts: N–H···O and O–H···O. The thermal behavior under air reveals two anomalies at 368 and 402 K attributed respectively to a structural phase transition probably due to the reorientation of ammonium tetrahedral and to the release of crystalline water. IR spectroscopy further confirms that this material loses crystallization water gradually in the temperature range 400–460 K. 相似文献9.
O. V. Yakubovich E. V. Yakovleva V. O. Yapaskurt O. V. Dimitrova 《Crystallography Reports》2014,59(2):160-165
The crystal structure of a new monoclinic variety of hydrous rubidium vanadyl phosphate [Rb0.24(H2O)0.76]VO(H2O)(PO4) doped with Al3+ ions is studied by X-ray (R = 0.054) diffraction: a = 6.2655(4) Å, b = 6.2712(3) Å, c = 6.8569(5) Å, β = 107.805(7)°, space group P21/m, Z = 2, and D x = 2.792 g/cm3. The new phase obtained by the hydrothermal synthesis in the V2O5-Rb2CO3-AlPO4-H2O system has a layer-type structure in which Rb atoms and water molecules are located between layers of vertexsharing [VO5(H2O)] octahedra and [PO4] tetrahedra. Rb intercalates based on VOPO4 · 2H2O are described by general formula [Rb x (H2O)1 ? x ]V 1?x V V x IV O(H2O)(PO4), where x ≤ 0.5, and the amount of reduced vanadium and interlayer water molecules is determined by the amount of introduced rubidium atoms. 相似文献
10.
Fangyong Su Baibin Zhou Zhifeng Zhao Zhanhua Su Chuncheng Zhu 《Crystal Research and Technology》2009,44(4):447-452
A new molybdenum arsenate, [Cu(imi)2]2[(CuO6)(As3O3)2Mo6O18][Cu(imi)2]2 ( 1 ) (imi = C3N2H4), has been synthesized under mild hydrothermal conditions, and characterized by elemental analysis, IR, thermogravimetric analyses, and single‐crystal X‐ray diffraction analysis. The polyanion framework derives from the Anderson structure in which the central octahedron is filled up by a copper (II), and is capped on both sides by two cyclic As3O6 groups. The countercations contain bisupported [Cu(imi)2]+ complex cations and two free [Cu(imi)2]+ complex cations. The electrochemical behavior of 1 ‐modified carbon paste electrode ( 1 ‐CPE) has been studied in detail. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
11.
Syntheses, structures, and electrochemistry of a dialkoxo‐bridged diuranyl(VI) compound [(UO2)2(L1)2(dimethylformamide)2] ( 1 ) and a mononuclear–mononuclear cocrystalline compound [(UO2)(L2)(H2O)⊂(H2O)]·[(UO2)(L2)(H2O)] ( 2 ) derived from Schiff base ligands are reported (H2L1 = Schiff base ligand obtained on condensation of 3‐ethoxysalicylaldehyde with 2‐aminoethanol; H2L2 = N,N ′‐o ‐phenylenebis(3‐ethoxysalicylaldimine)). The compounds 1 and 2 crystallize in the space groups P 21/c and P 1, respectively. Compound 1 is a dialkoxo‐bridged dinuclear compound of uranium(VI) containing two deprotonated ligands, [L]2–, two dimethylformamide (dmf) molecules and two UO22+ centers. Three C–H···O type hydrogen bonds involving one uranyl oxygen, two dmf hydrogens, and the imine hydrogen link the dinuclear units into a two‐dimensional network. Compound 2 is a cocrystal of two mononuclear units, [(UO2)(L2)(H2O)⊂(H2O)] (unit 1) and [(UO2)(L2)(H2O)] (unit 2). In unit 1, the non‐coordinated water molecule forms hydrogen bonds with oxygens of phenoxo, ethoxy, and coordinated water molecules resulting in the formation of an inclusion product. The overall supramolecular structure of compound 2 is one‐dimensional and consists of interlinked self‐assembled dimeric unit of unit 1 and unit 2. Cyclic voltammetric measurements reveal that the uranium(VI) center in [(UO2)2(L1)2(dimethylformamide)2] ( 1 ) is reduced quasireversibly at E1/2 = –773 mV with ΔEP = 121 mV, while the metal center in [(UO2)(L2)(H2O)⊂(H2O)]·[(UO2)(L2)(H2O)] ( 2 ) is reduced reversibly with E1/2 = –765 mV with ΔEP = 68 mV. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
12.
Two transition metal(II) complexes of betaine (Me3N+CH2COO–, designated as BET) and pyridine betaine (C5H5N+CH2COO–, pyBET) have been prepared and investigated by X-ray crystallography and infrared spectroscopy. [Ni(BET)2(H2O)4] (NO3)2 (1), (R
F=0.054 for 2518 observed MoK data) comprises slightly distorted octahedral [Ni(BET)2(H2O)4]2+ cations in which the Ni(II) atom is centrosymmetrically coordinated by four aqua ligands and twotrans-related unidentate BET ligands, and the uncoordinated carboxy oxygens form intramolecular hydrogen bonds with the aqua ligands. [Co(pyBET)4(H2O)2]·2[Co(pyBET)Cl3] (2) (R
F=0.029 for 4696 observed data) consists of discrete octahedral [Co(pyBET)4(H2O)2]2+ cations and tetrahedral [Co(pyBET)Cl3]– anions. In the centrosymmetric cation each of the twotrans-related aqua ligands form a pair of intramolecular hydrogen bonds with the uncoordinated oxygen atoms of two unidentate pyBET ligands. In the anion the cobalt atom is coordinated by one unidentate pyBET ligand and three chloro ligands. 相似文献
13.
C. G. Vonk 《Journal of chemical crystallography》1973,3(4):201-207
The structure of crystals of the composition Zn[Cl2Ti(C5H5)2]2·2C6H6 has been determined from Patterson and Fourier syntheses of two projections, and refined toR = 0·117 by full-matrix three-dimensional least-squares methods. The crystals are orthorhombic:Pbcn,a = 18·45(5),b = 15·40(6),c = 11·35(3) Å,Z= 4. The complex consists of a central distorted ZnCl
4
2–
tetrahedron linked along the Cl—Cl edges to two distorted TiCl2(C5H5)2
+ tetrahedra in such a way that their centres are nearly collinear The two C6H6 molecules in the formulae unit may be regarded as benzene of crystallization. 相似文献
14.
Xinwei Wu Jeremy D. Moskowitz John C. Mauro Marcel Potuzak Qiuju Zheng Rüdiger Dieckmann 《Journal of Non》2012,358(12-13):1430-1437
Sodium tracer diffusion coefficients, D*Na, have been measured using the radioactive isotope Na-22 in sodium boroaluminosilicate (NBAS) glasses containing either a small amount of As2O3 or Fe2O3. The chemical compositions of the first type of glasses are given by the formula [(Na2O)0.71(Fe2O3)0.05(B2O3)0.24]0.2[(SiO2)x(Al2O3)1 ? x]0.8 and those of the second type of glasses correspond to the formula [(Na2O)0.73(B2O3)0.24(As2O3)0.03]0.18[(SiO2)x(Al2O3)1 ? x]0.82. Tracer diffusion measurements were performed at different temperatures between 198 and 350 °C. Pre-annealing of the glass samples at their glass transition temperatures in common air was found to lead to changes in the values of sodium tracer diffusion coefficients. For the NBAS glasses containing Fe2O3, after pre-annealing for 5 h, the activation enthalpy derived for the sodium tracer diffusion increases almost linearly from 57.5 to 71.3 kJ/mol with a decrease in the alumina content while the pre-exponential factor of the sodium tracer diffusion coefficient increases from 2.1 · 10? 4 to 5.3 · 10? 4 cm2/s. For the iron-free NBAS glasses pre-annealed for 5 h, the activation enthalpy varies between 63.9 and 71.4 kJ/mol while the pre-exponential factor varies between 1.5 · 10? 4 and 1.2 · 10? 3 cm2/s. In addition, it was observed that the considered glasses take up water when annealed at 300 °C in wet air with PH2O = 474 mbar. 相似文献
15.
A novel homologous series of α-4-(4′-n-alkoxy cinnamoyloxy) phenyl β-2″-nitro, 3″–4″ di methoxy benzoyl ethylenes, H2n+1CnO?C6H4?CH?CH?COO?C6H4?CO?CH?CH?C6H2(NO2) (OCH3)2 (n = 1–8, 10, 12, 14, 16, 18) has been synthesized. All these compounds have been characterized by suitable spectroscopic techniques. C1 homologue is nonmesogenic, while C2 homologue shows enantiotropic nematogenic property and the rest of the homologous (C3?C18) displayed enantiotropically smectogenic plus nematogenic phase. Phase transition temperatures and textures of the LC phase were determined by an optical polarizing microscopy (POM) equipped with a heating stage. The mesomorphic properties of these compounds were confirmed by differential scanning calorimetry (DSC) analysis. 相似文献
16.
Wansheng You Zaiming Zhu Enbo Wang Lin Xu Changwen Hu 《Journal of chemical crystallography》2000,30(9):577-581
[(H3O)(C14H20O5)2][Me2NH2]2 [PMo12O40] · 2C14H20O5
1 was synthesized from benzo-15-crown-5 and H3PMo12O40·24H2O in N,N-dimethylformamide for the first time. 1 crystallizes in the monoclinic space group C2/c with a = 18.583(4), b = 25.510(5), c = 19.904(4) Å, = 94.66(3)° D
c = 2.124 mg/m3 for Z = 4. Refinement based on 7358 observed reflections led to a R1(wR2) = 0.0378(0.0761). The complex cation, [(H3O)(C14H20O5)2]+, exhibits a sandwich structure by hydrogen-bonding in the mean distance of 2.955 Å. The anion, PMo12O40
3–, is a -Keggin structure. 相似文献
17.
Both compounds of CuBr⋅C6H4N3(OC3H5) (sp. gr. P1, a = 7.633(1) Å, b = 9.987(1) Å, c = 14.898(2) Å, α = 104.75(1)∘, β = 94.76(1)∘, γ = 106.90(1)∘) (I) and 2CuCl⋅C6H4N3(OC3H5) (sp. gr. Cc, a = 11.2483(4) Å, b = 16.7076(6) Å, c = 7.2948(3) Å, β = 118.612(2)∘) (II) composition were prepared by alternating-current electrochemical synthesis. In I due to a bridging function of organic moieties 16-membered cycles appear which are combined into ribbons {Cu2Br2[(C6H4N3(OC3H5)]2}n. Each of two crystallographically independent copper atom possesses a trigonal-pyramidal arrangement with different degree of tetrahedral distortion. Distinctive numbers of hydrogen bonds around Br1 and Br2 atoms cause rather appreciable distinctions in copper–olefinic bond interaction effectiveness for each metal atom. In II Cu2Cl2 rhombs are joined to infinite chains oriented along [010] direction. Each ligand molecule is also coordinated through the C=C—bond of the allylic group to copper atom of one inorganic chain and through the nitrogen atom to a metal atom belonging to another copper-halide chain. Cu1 atoms is tetrahedrally surrounded by three chlorine atoms and nitrogen one, whereas a trigonal-planar arrangement of Cu2 atom is formed by two halogen atoms and slightly disordered olefinic group. 相似文献
18.
L. B. Serezhkina A. V. Vologzhanina N. A. Neklyudova V. N. Serezhkin 《Crystallography Reports》2009,54(1):59-62
Single crystals of the compound {NH2(C2H5)2}2[(UO2)2C2O4(CH3COO)4] · 2H2O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 9.210(2) ?, b = 14.321(3) ?, c = 12.659(3) ?, β = 105.465(13)°, V = 1609.2(6) ?3, space group P21/c, Z = 2, and R = 0.0198. The structural units of crystals I are binuclear groups of the composition [(UO2)2C2O4(CH3COO)4]2− with an island structure, which belong to the crystal-chemical group A
2
K
02
B
401 (A = UO22+, K
02 = C2O42−, B
01 = CH3COO−) of the uranyl complexes, diethylammonium cations, and water molecules. The uranium-containing groups are joined into a three-dimensional
framework through electrostatic interactions with diethylammonium cations and a system of hydrogen bonds, which are formed
with the participation of the atoms involved in the composition of the water molecules, oxalate ions, acetate ions, and diethylammonium
cations.
Original Russian Text ? L.B. Serezhkina, A.V. Vologzhanina, N.A. Neklyudova, V.N. Serezhkin, 2009, published in Kristallografiya,
2009, Vol. 54, No. 1, pp. 65–67. 相似文献
19.
I. V. Medrish E. V. Peresypkina A. V. Virovets L. B. Serezhkina 《Crystallography Reports》2008,53(3):462-465
Three heteroacidoligand uranyl complexes M
4[(UO2)2C2O4(SO4)2(NCS)2] (M = K+ (I), Rb+ (II)) and K4[(UO2)2C2O4(SeO4)2(NCS)2] (III) have been synthesized and their crystal structure has been determined by X-ray diffraction analysis. The compounds I–III are isostructural and crystallized in the monoclinic system, sp. gr. P21/c, Z = 2, a = 11.5548(3) ?, b = 7.0847(1) ?, c = 13.5172(3) ?, β = 93.130(1)°, V = 1104.90(4), R = 0.015 (I); a = 11.5854(9) ?, b = 7.3841(6) ?, c = 13.9072(9) ?, β = 95.754(3)°, V = 1183.74(15), R = 0.0235 (II); a = 11.6715(3) ?, b = 7.1418(2) ?, c = 13.8546(1) ?, β = 93.539(1)°, V = 1152.66(5), R = 0.0126 (III). Basic structural units of these crystals are [(UO2)2C2O4(XO4)2(NCS)2]4− chains, which belong to the crystallochemical group A
2
K
02
B
22
M
21 (A = UO22+, K
02 = C2O2−4, B
2 = SO42− or SeO42−, M
1 = NCS−) of uranyl complexes. Uranium-containing chains are connected into a 3D framework via a system of electrostatic interactions
with potassium or rubidium cations from outer spheres.
Original Russian Text ? I.V. Medrish, E.V. Peresypkina, A.V. Virovets, L.B. Serezhkina, 2008, published in Kristallografiya,
2008, Vol. 53, No. 3, pp. 495–498. 相似文献
20.
Raj Pal Sharma Rajni Sharma Ritu Bala Dip Singh Gill Sukhjinder Singh Jugal Kishor Puri Luca Russo Kari Rissanen 《Journal of chemical crystallography》2006,36(10):619-625
The cobalt(III) complex salt [(C4H9)4N][trans-Co(NH3)2(NO2)4] has been synthesized in high yield by reacting equimolar quantities of [(C4H9)4N]Br and K[trans-Co(NH3)2(NO2)4] in aqueous medium at room temperature. The product thus formed has been re-crystallised from acetone-water mixture, in the monoclinic space group P 21/n, with cell dimensions a=11.651(3) ?, b=19.005(4) ?, c=11.733(5) ?, β=90.28(3)°. The X-ray structure determination revealed the presence of discrete ions, [(C4H9)4N]+ and [trans-Co(NH3)2(NO2)4]−. The central metal ion cobalt(III) in the anion is found in octahedral environment, in trans geometry, while the organic counterion is a quaternary alkylammonium cation. The crystal lattice is stabilized by electrostatic interactions between the cations and anions.Supplementary material Crystallographic data (excluding structure factors) for the structure(s) reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC 291300. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: (44) 1223 336-033; e-mail: deposit@ccdc.cam.ac.uk. 相似文献