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1.
The solid-state coordination reaction: Nd(NO3)3·6H2O(s)+4Ala(s) → Nd(Ala)4(NO3)3·H2O(s)+5H2O(l) and Er(NO3)3·6H2O(s)+4Ala(s) → Er(Ala)4(NO3)3·H2O(s)+5H2O(l) have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products in 2 mol L–1 HCl solvent of these two solid-solid coordination reactions have been measured using a calorimeter. From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(Ala)4(NO3)3·H2O, s, 298.2 K] and[Er(Ala)4(NO3)3·H2O, s,298.2 K] at 298.2 K have been determined to be Δf H m 0 [Nd(Ala)4(NO3)3·H2O,s, 298.2 K]=–3867.2 kJ mol–1, and Δf H m 0 [Er(Ala)4(NO3)3·H2O, s, 298.2 K]=–3821.5 kJ mol–1. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

2.
The constant-volume combustion energies of the lead salts of 2-hydroxy-3,5-dinitropyridine (2HDNPPb) and 4-hydroxy-3,5-dinitropyridine (4HDNPPb), ΔU c (2HDNPPb(s) and 4HDNPP(s)), were determined as –4441.92±2.43 and –4515.74±1.92 kJ mol–1 , respectively, at 298.15 K. Their standard enthalpies of combustion, Δc m H θ(2HDNPPb(s) and 4HDNPPb(s), 298.15 K), and standard enthalpies of formation, Δr m H θ(2HDNPPb(s) and 4HDNPPb(s), 298.15 K) were as –4425.81±2.43, –4499.63±1.92 kJ mol–1 and –870.43±2.76, –796.65±2.32 kJ mol–1 , respectively. As two combustion catalysts, 2HDNPPb and 4HDNPPb can enhance the burning rate and reduce the pressure exponent of RDX–CMDB propellant.  相似文献   

3.
Single crystals of Cs4[(UO2)2(C2O4)(SO4)2(NCS)2] · 4H2O (I) and (NH4)4[(UO2)2(C2O4)(SO4)2(NCS)2] · 6H2O (II) have been synthesized and studied by X-ray diffraction. The crystals of both compounds are orthorhombic with the space group Pbam, Z = 2, and unit cell parameters a = 12.0177(3) ?, b = 18.6182(5) ?, c = 6.7573(10) ?, R = 0.0376 (I); a = 11.6539(9) ?, b = 18.3791(13) ?, c = 6.7216(5) ?, R = 0.0179 (II). The main structural units of crystals I and II are [(UO2)2(C2O4)(SO4)2(NCS)2]4− chains belonging to the crystal-chemical group A2K02B22M21 (A = UO22+, K02 = C2O42−, B2 = SO42−, M1 = NCS) of the uranyl complexes. The uranium-containing chains are joined into a three-dimensional framework due to a system of electrostatic interactions with the cesium or ammonium ions in the structure of I. In the structure of II, this framework is additionally stabilized by hydrogen bonds involving the outer-sphere water molecules and ammonium ions. Original Russian Text ? I.V. Medrish, A.V. Virovets, E.V. Peresypkina, L.B. Serezhkina, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 7, pp. 1115–1120.  相似文献   

4.
Thermal and structural properties of model silicate-phosphate glasses containing the different amounts of the glass network modifiers, i.e. Mg2+ and Ca2+ were studied. To explain the changes of the parameters characterizing the glass transition effect (Tg, Δcp) and the crystallization process (Tc, ΔH) depending on the cations modifiers additions, analysis of the bonds and chemical interactions of atoms in the structure of glasses was used. 31P MAS-NMR spectra of SiO2–P2O5–MgO(CaO)–K2O glasses show that the phosphate complexes are mono- and diphosphate. It has been found that increasing amounts of Mg2+ or Ca2+ cations in the structure of glasses causes the reduction of the degree of polymerization of the phosphate framework (Q1→Q0). The influence of increasing of modifiers in the structure of silicate- phosphate glasses on the number of non-bridging oxygens per SiO4 tetrahedron and density of glasses was presented.  相似文献   

5.
Single crystals of (CN3H6)2[(UO2)2(C2O4)(SeO3)2] were synthesized and studied by IR spectroscopy and X-ray diffraction. The compound crystallizes in the triclinic system with the unit cell parameters a = 7.1169(12) ?, b = 7.4874(10) ?, c = 8.9748(14) ?, α = 88.243(6)°, β = 74.546(6)°, γ = 81.445(6)°, space group P[`1]P\bar 1, Z = 1, R = 0.0304. The main structural units of the crystals are layers of the [(UO2)2(C2O4)(SeO3)2]2− composition; the layers belong to the crystal chemical group A 2 K 02 T 23 (A = UO22+ K 02 = C2O42−, T 3 = SeO3) of uranyl complexes. Uranium-containing complex groups are linked by electrostatic interactions and a network of hydrogen bonds with CN3H6+ guanidinium ions to form a three-dimensional framework.  相似文献   

6.
Low-temperature heat capacities of a solid complex Zn(Val)SO4·H2O(s) were measured by a precision automated adiabatic calorimeter over the temperature range between 78 and 373 K. The initial dehydration temperature of the coordination compound was determined to be, T D=327.05 K, by analysis of the heat-capacity curve. The experimental values of molar heat capacities were fitted to a polynomial equation of heat capacities (C p,m) with the reduced temperatures (x), [x=f (T)], by least square method. The polynomial fitted values of the molar heat capacities and fundamental thermodynamic functions of the complex relative to the standard reference temperature 298.15 K were given with the interval of 5 K. Enthalpies of dissolution of the [ZnSO4·7H2O(s)+Val(s)] (Δsol H m,l 0) and the Zn(Val)SO4·H2O(s) (Δsol H m,2 0) in 100.00 mL of 2 mol dm–3 HCl(aq) at T=298.15 K were determined to be, Δsol H m,l 0=(94.588±0.025) kJ mol–1 and Δsol H m,2 0=–(46.118±0.055) kJ mol–1, by means of a homemade isoperibol solution–reaction calorimeter. The standard molar enthalpy of formation of the compound was determined as: Δf H m 0 (Zn(Val)SO4·H2O(s), 298.15 K)=–(1850.97±1.92) kJ mol–1, from the enthalpies of dissolution and other auxiliary thermodynamic data through a Hess thermochemical cycle. Furthermore, the reliability of the Hess thermochemical cycle was verified by comparing UV/Vis spectra and the refractive indexes of solution A (from dissolution of the [ZnSO4·7H2O(s)+Val(s)] mixture in 2 mol dm–3 hydrochloric acid) and solution A’ (from dissolution of the complex Zn(Val)SO4·H2O(s) in 2 mol dm–3 hydrochloric acid).  相似文献   

7.
The alkylation of ethylenediamine with allyl bromide in the presence of a fourfold (with respect to ethylenediamine) molar amount of NaHCO3 in acetone with an ethanol admixture (15: 1) affords LBr2 · 2H2O (I), where L2+ is the N,N,N,N′,N′,N′-hexaallylethylenediaminium cation. Single crystals of complexes L[CuII(Br0.45Cl3.55)] (II), L[Cu4I(Br4.55Cl1.45)] (III), and L[Cu4IBr6] (IV) are prepared by ac electrochemical synthesis from an ethanolic solution of LBr2 · 2H2O, CuCl2 · 2H2O (or CuBr2) at copper wire electrodes. The crystal structures of compounds I–IV are determined by X-ray diffraction analysis. The crystals of complex I are monoclinic: space group P21/n, a = 8.544(3), b = 10.404(3), c = 13.350(4) ?, β = 97.29(3)°, V = 1177.2(6) ?3, Z = 2. The bromine anions in compound I are bonded to the L2+ cations and water molecules through hydrogen contacts (E)H…Br (E = O, C) of 2.57(3)–2.86(3) ?. The crystals of compounds II–IV are triclinic: space group P . For II: a = 8.762(4), b = 9.163(4), c = 16.500(6) ?, α = 95.62(4)°, β = 96.39(4)°, γ = 111.46(4)°, V = 1211.4(9) ?3, Z = 2; for III: a = 9.074(4), b = 9.435(4), c = 9.829(5) ?, α = 116.12(4)°, β = 104.14(4)°, γ = 100.22(4)°, V = 692.3(6) ?3, Z = 1; for IV isostructural III: a = 9.084(4), b = 9.404(4), c = 9.869(4) ?, α = 116.31(3)°, β = 104.00(3)°, γ = 100.37(3)°, V = 692.1(5) ?3, Z = 1. Unlike the isolated tetrahedral CuX42− anion in structure II, an original chain anion (Cu4X62−) n is observed in the structures of π complexes III and IV. Original Russian Text ? M.M. Monchak, A.V. Pavlyuk, V.V. Kinzhibalo, M.G. Mys’kiv, 2009, published in Koordinatsionnaya Khimiya, 2009, Vol. 35, No. 6, pp. 414–419.  相似文献   

8.
The conformational behavior of 1,2-difluoroethane (1), 1,2-dichloroethane (2), 1,2-dibromoethane (3), and 1,2-diiodoethane (4) have been analyzed by means of complete basis set CBS-QB3, hybrid-density functional theory (B3LYP/Def2-TZVPP) based methods and natural bond orbital (NBO) interpretation. Both methods showed the expected greater stability of the gauche conformation of compound 1 compared to its anti conformation. Contrary to compound 1, the anti conformations of compounds 24 are more stable than their gauche conformation. The stability of the anti conformation compared to the gauche conformation increases from compound 1 to compound 4. The NBO analysis of donor–acceptor (σ → σ*) interactions showed that the generalized anomeric effect (GAE) is in favor of the gauche conformation of compound 1. Contrary to compound 1, GAE is in favor of the anti conformations of compounds 24. The GAE values calculated (i.e., GAEanti − GAEgauche) increase from compound 1 to compound 4. On the other hand, the calculated dipole moment values for the gauche conformations decrease from compound 1 to compound 4. In the conflict between the GAE and dipole moments, the former succeeded in accounting for the increase of the anti conformation stability from compound 1 to compound 4. There is a direct correlation between the calculated GAE, ∆[r c–c(G) − r c–c(A)] and ∆[r c–x(A) − r c–x(G)] parameters. The correlations between the GAE, bond orders, total steric exchange energies (TSEEs), ΔG Anti–Gauche, ΔG (Gauche → Gauche′, C 2v), ΔG (Anti → Gauche, C 2), dipole–dipole interactions, structural parameters, and conformational behaviors of compounds 14 have been investigated.  相似文献   

9.
The structure and conducting properties of a new radical cation salt of dibenzotetrathiafulvalene (DBTTF),viz., (DBTTF)11(TeCl6)4 (1), were studied. According to the X-ray diffraction data, the crystal of1 contains six crystallographically independent DBTTF radical cations alternating with stacks of the (TeCl6)2− anions. At room temperature, the conductivity of the crystals is 15 S cm−1 and it changes exponentially as the temperature decreases. It was found that an increase in the size of the anion in compounds of type1 results in the appearance of interactions between the stacks and in an enhancement of the two-dimensional character of the conductivity. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 370–372, February, 2000.  相似文献   

10.
A series of trichlorogermyl-substituted dicarboxylic acids of general formula HOOC–R′–COOH where R′=–CH2CH(GeCl3)CH21, –CH(CH2GeCl3)CH22, –CH(GeCl3)CH23 and –CH(CH3)CH(GeCl3)– 4 were synthesized by the hydrogermylation reaction of unsaturated acids, such as trans-glutaconic (2-pentenedioic acid), itaconic (methylenebutanedioic acid), fumaric (2-butenedioic acid), and citraconic (2-methyl-2-butenedioic acid) acids with HGeCl3, which was produced in situ by the reaction of GeO2 with 37% HCl in presence of NaH2PO2 · H2O. All these compounds were characterized by melting point, CHN analysis, FTIR, and multinuclear NMR (1H; 13C; H,H-COSY). X-Ray crystal structures of 1 and 2 were analyzed to show supramolecular structures in which central Ge atom in each of these structures is four-coordinated with a slightly distorted tetrahedral geometry. Structurally, both compounds adopt supramolecular forms via strong intermolecular O–H–O interactions through 8-membered and 22-membered hydrogen bonded rings. Supplementary material to this paper is available in electronic form at Correspondence: Muhammad Mazhar, Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan.  相似文献   

11.
The kinetics of protonation of tungsten hydrides WH(CO)2(NO)L2 (1, L = PMe3, PEt3, P(OPri)3, PPh3) by weak OH-acids (PhOH, (CF3)2CHOH, (CF3)3COH) in hexane was studied by IR spectroscopy. The study of the reactions of compounds 1 with OH-acids at 190–270 K revealed that the first step involves the formation of dihydrogen-bonded W(CO)2(NO)L2(H)...HOR complexes. When the temperature increases to ambient, the proton transfer and evolution of molecular hydrogen occur, affording the final products: organyloxy derivatives W(OR)(CO)2(NO)L2. The study of the kinetics at 298 K found that the proton transfer is the rate-determining step. The rate constants k app are 2.2·10−5–6.3·10−4 s−1, and the free activation energies are ΔG 298K = 22–23 kcal mol−1. The rate constants depend on the proton-accepting properties of the hydride and the acidic properties of the OH-proton donor and increase in the same order as the enthalpy of hydrogen bond formation. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 837–841, May, 2007.  相似文献   

12.
1H and 13C NMR chemical shifts have been determined and assigned based on PFG 1H, 13C HMQC, and HMBC experiments for 3-(4′-X-benzyl)-4-chromenones (Ia, X = CN and Ib, X = NO2), 3-(4′-X-benzyl)-4-thiochromenones (IIa, X = Cl and IIb, X = Br), (E)-3-(4′-X-benzylidene)-4-chromanones (IIIaIIIe, X = OCH3, CH3, Cl, N(CH3)2, Br), (Z)-3-(4′-X-benzylidene)4-thiochromanones (IVaIVd, X = Cl, Br, F, OCH3), 2-benzyl-1,2,3,4-tetrahydro-1-naphthol (V), 2-benzyl- and (E)-2-benzylidene-1-tetralones (VI and VII), and (E)-2-benzylidene-1-benzosuberol (VIII). The crystal structures have been determined for the following seven compounds: derivatives of 4-chromanones (IIIaIIId), 1-tetrahydronaphtol (V), and 1-tetralones (VI and VII). The molecular features and intermolecular interactions in crystal state have been discussed.  相似文献   

13.
Two binuclear cadmium(II) iodide compounds of the types [Cd2(L1)(I)4] (1) and [(L2)Cd(μ-I)CdI3] (2) [L1 = N,N′-(bis(pyridine-2-yl)formylidene)triethylenetetramine and L2 = tris(2-aminoethyl)amine] are synthesized and characterized. X-ray structural study shows that each cadmium(II) in 1 has a distorted square pyramidal geometry with a CdN3I2 chromophore and that L1 behaves as a binucleating bis(tridentate) ligand bridging the metal centers with iodides remaining as terminals. In 2, one cadmium(II) adopts a distorted tetrahedral geometry with a CdI4 chromophore surrounded by four iodides, while the other has a distorted trigonal bipyramidal environment with CdN4I chromophore bound by four N atoms of L2 and one bridging iodide. Weak C–H···π interactions in 1 result in an infinite 1D chain; however, such weak non-covalent interactions are absent in 2. The Schiff base complex, 1, shows high-energy intraligand 1(π–π*) fluorescence in DMF solution at room temperature, whereas compound 2 containing tripodal amine is fluorescent-inactive.  相似文献   

14.
The microstructure of the normal micelles formed by dimeric surfactants with long spacers, [Br(CH3)2N+(C m H2 m +1)-(CH2) S  -(C m H2 m +1)N+(CH3)2Br, m = 10 and s = 8, 10 and 12], has been investigated by small-angle neutron scattering and compared with previously reported results for micelles of the same dimeric surfactants with shorter spacers (m = 10 and s = 2, 3, 4 and 6). It was found that for dimeric surfactants with long spacers (s = 8 and 10), both micellar growth and variation in shape occur to only a small extent, if at all, compared with dimeric surfactants with short spacers. However, for the dimeric surfactant with the longest spacer, s = 12, the extent of micellar growth and shape variation is also large. These results are due to the differences in conformation of dimeric surfactants with short spacers (s = 2–6) compared with that of the surfactants with long spacers (s = 8–12). Received: 15 June 1998 Accepted: 22 July 1998  相似文献   

15.
X-ray phase and X-ray spectral analyses are performed for newly synthesized M(Aet)2·11H2O compounds, where M(II) = Mn, Mg, and Mg0.5Mn0.5, (Aet) = (C10H11N4O2S2), the anion of ethazol (2-(paraaminobenzene sulfanilamide)-5-ethyl-1,3,4-thiadiazole). It is found that these compounds are isostructural. In the third compound, Mg and Mn statistically substitute for each other and the substitution takes place at any ratio of these metals. The structure of crystals of the [Mn(OH2)6](Aet)2·5H2O compound is studied: a = 17.160(2) ?, b = 14.115(1) ?, c = 15.130(2) ?, β = 98.23(3)°, P21/n, Z = 4, R(F) = 0.045. The compound consists of complex [Mn(OH2)6]2+ hexaaqua cations, (Aet) anions, and five water molecules. Original Russian Text Copyright ? 2009 by é. B. Miminoshvili, K. é. Miminoshvili, and L. A. Beridze __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 1, pp. 177–182, January–February, 2009.  相似文献   

16.
Two long-chain multidentate ligands: 2,9-di-(n-2′,5′,8′-triazanonyl)-1,10-phenanthroline (L1) and 2,9-di-(n-4′,7′,10′-triazaundecyl)-1,10-phenanthroline (L2) were synthesized. The hydrolytic kinetics of p-nitrophenyl phosphate (NPP) catalyzed by complexes of L1 and L2 with La(III) and Gd(III) have been studied in aqueous solution at 298 K, I = 0.10 mol · dm−3 KNO3 at pH 7.5–9.1, respectively. The study shows that the catalytic effect of GdL1 was the best in the four complexes for hydrolysis of NPP. Its kLnLH−1, k LnL and pK a are 0.0127 mol−1 dm3 s−1, 0.000022 mol−1 dm3 s−1 and 8.90, respectively. This paper expounds the result from the structure of the ligands and the properties of the metal ions, and deduces the catalysis mechanism.  相似文献   

17.
The kinetics and mechanism of photodehydrogenation of the phosphine hydride complexes MH4L4 (M = Mo, W; L are phosphine ligands) and the formation of coordinatively unsaturated species ML4 were studied by the absorbance of long-wavelength bands with λmax at 450–460 nm appeared in the absorption spectra of the photoproducts. The rate constants of the reactions of the coordinatively unsaturated M(DPPE)2 species (M = Mo, W; DPPE = Ph2PCH2CH2PPh2) with molecular nitrogen in benzene were determined (k W = 200 s−1, k Mo = 8700 s−1). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 282–284, February, 2008.  相似文献   

18.
Thermodynamic stability of CdMoO4 was determined by measuring the vapor pressures of Cd and MoO3 bearing gaseous species. Th vaporization reaction could be described as CdMoO4(s)+MoO2(s) =Cd(g)+2/n(MoO3)n (n=3, 4 and 5). The vapor pressures of the cadmium (p Cd) and trimer (p (MoO3)3) measured in the temperature range 987≤T/K≤1111 could be expressed, respectively, as ln (p Cd/Pa) = –32643.9/T+29.46±0.08 and ln(p (MoO3)3/Pa) = –32289.6/T+29.28±0.08. The standard molar Gibbs free energy of formation of CdMoO4(s), derived from the vaporization results could be expressed by the equations: °f G CdMoO4 (s) 0= –1002.0+0.267T±14.5 kJ mol–1 (987≤T/K≤1033) and °f G CdMoO4 (s) 0 = –1101.9+0.363T±14.4 kJ mol–1 (1044≤T/K≤1111). The standard enthalpy of formation of CdMoO4(s) was found to be –1015.4±14.5 kJ mol–1 .  相似文献   

19.
The structures of rare earth dichalcogenides are investigated. The symmetry and unit cell parameters are considered, and their relationship with those of the PbFCl and anti-Cu2Sb structural prototypes is analyzed. The interatomic distances in the Ln3+, X2−, and (X2)2− layers and the compatibility factors are examined. It is discussed how the degree of polymerization of the chalcogen ions in the (X2)2− layers and the compatibility of the latter with the Ln3+ and X2− layers affect the symmetry and the twinning and polymorhism abilities of the compounds. Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 6, pp. 1140–1170, November–December, 1996. Translated by L. Smolina  相似文献   

20.
Mixed-ligand complexes CdPhen(i-BuOCS2)2 (I) and CdPhen(n-BuOCS2)2 (II) have been synthesized. Their structures were solved using X-ray diffraction data (X8 APEX diffractometer, MoK α radiation, 1641 and 2497 F hkl , R = 0.0359 and 0.0389). Crystals I are orthorhombic with unit cell parameters a = 6.5883(3) Å, b = 19.7123(10) Å, c = 20.1936(11) Å, V = 2622.6(2) Å3; Z = 4, space group Pbcn; crystals II are monoclinic, a = 6.5845(2) Å, b = 19.1522(6) Å, c = 20.7091(7) Å, β = 97.106(1), V = 2591.5(1) Å3, Z = 4, space group C2/c. The structures consist of discrete mononuclear molecules in which the coordination polyhedron of the Cd atom is a distorted N2S4 octahedron. Molecular packing and interactions in the structures are discussed. Original Russian Text Copyright ? 2007 by R. F. Klevtsova, T. G. Leonova, L. A. Glinskaya, and S. V. Larionov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 48, No. 2, pp. 274–281, March–April, 2007.  相似文献   

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