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1.
Infrared and Raman spectra have been collected and analyzed for n-pentane and n-pentane-d12. The real (n) and imaginary (k) refractive index spectra for each compound have been calculated from the experimental infrared spectra after determining the refractive indices of n-pentane across the visible region of the electromagnetic spectrum. To further aid in the study, the imaginary polarizability (IP) spectrum for each compound was calculated from the n and k spectra, then curvefit to separate intensities. Computational DFT calculations were performed to create theoretical spectra of each compound, which in turn aid in assigning vibrations in the experimental spectrum. Barriers to rotation for n-pentane were explored to determine the dominant conformations. 相似文献
2.
With various concentrations of CaCl2 and MgCl2 aqueous solution below 1.0 mol/l, Raman spectra of water in the OH stretch region of 2500-4000 cm−1 and 17O NMR chemical shift of water are measured and the Raman spectra are deconvoluted. Both Raman spectra and 17O NMR of water show that the effect of Ca2+ on water structure is stronger than that of Mg2+. CaCl2 and MgCl2 destroy four hydrogen bonded water structure, but promote median water cluster size. 相似文献
3.
B. Sieklucka W.
asocha L. M. Proniewicz R. Podgajny H. Schenk 《Journal of Molecular Structure》2000,520(1-3):155-163
The bimetallic [Pt(NH3)4]2[W(CN)8][NO3]·2H2O is characterised by single-crystal X-ray diffraction [S.G.P21/m(11), a=8.0418(7), b=19.122(2), c=9.0812(6) Å, Z=2]. All platinum centres have the square-plane D4h geometry with average dimensions Pt(1)–N 2.042(2) and Pt(2)–N 2.037(10) Å. The octacyanotungstate anion has the square-antiprismatic D4d configuration with average dimensions W(1)–C 2.164(13), C–N 1.140(12), W(1)–N 3.303(5) Å. The structure exhibits two different mutual orientations of Pt versus W units resulting in Pt(2)–W(1), W(1)* separations of 4.77(2), 4.55(2)* and Pt(1)–W(1) of 6.331(8) Å. A centrosymmetric structure reveals groups of two distinct columns: the first is formed by intercalated NO3− between parallel [Pt(1)(NH3)4]2+ planes and the second consists of [W(CN)8]3− interlayered by, parallel to square faces of W-antiprisms, [Pt(2)(NH3)4]2+. The structure is stabilised through a three-dimensional hydrogen bond network via nitrogen atoms of cyanide ligands, hydrogen atoms of NH3 ligands, water molecules and oxygen atoms of NO3− counteranions. The vibrational pattern and the range of ν(CN) frequencies attributable to the electronic environment of W(V) and W(IV) are consistent with the ground state Pt(II)↔W(V) charge transfer. 相似文献
4.
G. Haxhillazi 《Journal of solid state chemistry》2004,177(9):3045-3051
The compounds (NH4)3[Ta(O2)4], K3[Ta(O2)4], Rb3[Ta(O2)4] and Cs3[Ta(O2)4] have been prepared and investigated by X-ray powder methods as well as Raman- and IR-spectroscopy. In the case of Rb3[Ta(O2)4] the structure has been solved from single crystal data. It is shown that all these compounds are isotypic and crystallize in the K3[Cr(O2)4] type (SG , No. 121). The infrared- and Raman spectra (recorded on powdered samples) are discussed with respect to the internal vibrations of the peroxo-group and the dodecahedral [Ta(O2)4]3− ion. Symmetry coordinates for the [Ta(O2)4]3− ion are given from which the vibrational modes of the O-O stretching vibrations of the O22− groups, the Ta-O stretching vibrations and the Ta-O bending vibrations are deduced. 相似文献
5.
Mehmet Karabacak Dilek Karagz Mustafa Kurt 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,72(5):1076-1083
In this work, the experimental and theoretical vibrational spectra of 2-chloro-4-methylaniline (2Cl4MA, C7H8NCl) were studied. FT-IR and FT-Raman spectra of 2Cl4MA in the liquid phase have been recorded in the region 4000–400 cm−1 and 3500–50 cm−1, respectively. The structural and spectroscopic data of the molecule in the ground state have been calculated by using Hartree-Fock (HF) and density functional method (B3LYP) with the 6-31G(d), 6-31G(d,p), 6-31+G(d,p), 6-31++G(d,p) and 6-311G(d), 6-311G(d,p), 6-311+G(d,p), 6-311++G(d,p) basis sets. The vibrational frequencies have been calculated and scaled values have been compared with experimental FT-IR and FT-Raman spectra. The observed and calculated frequencies are found to be in good agreement. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The DFT-B3LYP/6-311++G(d,p) calculations have been found more reliable than the ab initio HF/6-311++G(d,p) calculations for the vibrational study of 2Cl4MA. The optimized geometric parameters (bond lengths and bond angles) were compared with experimental values of aniline and p-methylaniline molecules. 相似文献
6.
The reaction of Cu(OH)2 and 2-hydrazino-2-imidazoline hydrobromide surprisingly resulted in complex compound where Cu(II) ions are chelated by a new ligand, namely bisimidazoline (biz). As has been found in the X-ray analysis, the [Cu(biz)2]2+ cations are accompanied by [Cu2Br4]2− anions, which makes the whole compound of metal-mixed-valency type. Both ions are centrosymmetric and quasi-planar. The Cu(II) coordination environment is a rectangle with almost equal Cu–N bond lengths (1.984(3), 1.987(3) Å). The electrostatic interaction of both complex ions is strengthened by two strong N–H···Br and four weaker (C–H···Br, C–H···N) hydrogen bonds. The relatively simple IR and Raman spectra were interpreted with help of quantum calculations carried out at the B3LYP/LanL2DZ level. The characterization of computed normal vibrations and correlating observed bands is given in terms of approximate D2h symmetry. The most intense band resulting from the Cu–N stretching vibration (B3u) was located at 342 cm−1, by 63Cu and 65Cu isotope substitution. The chemical reactions leading to the formation of presented compound are also proposed. 相似文献
7.
The core-shell structural (BaTiO(C2O4)2/NH2CONH2) samples of giant electrorheological (ER) activity have been synthesized by a sol-gel method and studied by TEM, X-ray diffraction and IR spectroscopy. From the analysis of the X-ray diffraction, it is found that the component of samples is (BaTiO(C2O4)2/NH2CONH2) with a different content of urea. The observations of the TEM morphology show that (BaTiO(C2O4)2/NH2CONH2) particles are spheral with a size of around 80 nm and a surface coating with 5-10 nm thickness consisting of urea. The samples show an increasing tend of ER effect as the addition of urea increasing. Moreover, by IR spectroscopy study, it is revealed that some peaks of CO band and C-O band vibrations of BaTiO(C2O4)2 are split into two peaks after urea added. The extent of the splits increase with the increase of urea content, which is resulted by the interaction between the chemical bonds of urea and oxalate of BaTiO(C2O4)2. It is evident that the giant ER activity of the sample has a close relationship with the interfacial polarization between the core and the shell of (BaTiO(C2O4)2/NH2CONH2). 相似文献
8.
[Co(amp)2Cl2]2[ZnCl4]体系中两对称异构体的2D NMR研究 总被引:7,自引:0,他引:7
The two symmetrical isomers in [Co(amp)2Cl2]2[ZnCl4](amp=2-(Aminomethyl)pyridine) system were syn-thesized by general oxidation method and were separated by chromatography and recrystallization method. Their configurations were assigned by using 2D NMR techniques, particularly the NOESY NMR spectra. Solvent used was Me2SO-d6 with the central peak of the CD3 septet as the reference ( 13C,δ 39.37; 1H,δ 2.49 relative to SiMe4). Cation exchange media used was Dowex 50Wx 2(H+ form, 200~400mesh; Biorad). 相似文献
9.
Yu Yang 《Journal of fluorine chemistry》2004,125(12):1825-1828
A stable carbocation was prepared by reacting bis(2-chloro-2,2-difluoroethyl) difluoroformal with SbF5. The carbocation's structure was confirmed by 19F, 1H and 13C NMR measurements. The carbocation is stable at room temperature for more than 2 weeks and was converted into the corresponding carbonate when reacted with water. 相似文献
10.
Mohamed El Masloumi Inhar Imaz Jean-Pierre Chaminade Michel Couzi Mohamed Maazaz 《Journal of solid state chemistry》2005,178(11):3581-3588
The single crystals of lanthanum metaphosphate MLa(PO3)4 (M=Na, Ag) have been synthesized and studied by a combination of X-ray crystal diffraction and vibrational spectroscopy. The sodium and silver compounds crystallize in the same monoclinic P21/n space group ( factor group) with the following respective unit cell dimensions: a=7.255(2), b=13.186(3), , β=90.40(2)°, , Z=4 and a=7.300(5), b=13.211(9), , β=90.47(4)°, , Z=4. This three-dimensional framework is built of twisted zig-zag chains running along a direction and made up of PO4 tetrahedra sharing two corners, connected to the LaO8 and NaO7 or AgO7 polyhedra by common oxygen atoms to the chains. The infrared and Raman vibrational spectra have been investigated. A group factor analysis leads to the determination of internal modes of (PO3)− anion in the phosphate chain. 相似文献
11.
J.R. Durig M.G. Griffin P.J. Cooper A.J. Zozulin J.D. Odom 《Journal of Molecular Structure》1978,44(2):133-141
The IR spectra of gaseous and solid (PF2)2O has been recorded from 80 to 1200 cm?1. The Raman spectra of gaseous, liquid and solid (PF2)2O have also been obtained (30–1000 cm?1). The spectra of the fluid phases indicate the presence of at least two conformers. The spectrum of the solid phase can readily be interpreted on the basis of a single conformer possessing a symmetry lower than C2v. A vibrational assignment is proposed for all normal modes except the PF2 torsions. The results are compared with similar data of related compounds. There appear to be two molecules per primitive cell based upon the low-frequency Raman data. 相似文献
12.
Rajni Sharma Raj Pal Sharma Paloth Venugopalan Miguel Quirs Juan M. Salas J. Yu Y. Du 《Journal of Molecular Structure》2008,885(1-3):7-14
[cis-Co(en)2(N3)2]C7H3ClNO4·1.25H2O (Cocnb) was synthesised and detailed packing analyses were undertaken to delineate the topological complementarity of [cis-Co(en)2(N3)2]+ and a 2-chloro-4-nitro benzoate anion (cnb) for second sphere coordination in the crystal lattice. The complex was completely characterised by elemental analyses, spectroscopic studies (IR, UV/visible, 1H and 13C NMR). The compound crystallizes in the monoclinic (space group C2/c) with a = 21.9843(18), b = 8.7959(7), c = 23.0121(18) Å, β = 116.426(1)°, V = 3984.9(6) Å3, and Z = 8. In the crystal lattice, discrete ions of [cis-Co(en)2(N3)2]+ and cnb are arranged in A–B–A–B pattern (in both a and c directions of the lattice) forming columns of anions and cations. The anionic columns are π stacked and are involved in extensive hydrogen bonding interaction. It appears that the topological feature of [cis-Co(en)2(N3)2]+ is conducive for generating second sphere interactions with aromatic carboxylates. This strategy may be used as a viable method for the capture of aromatic carboxylate anions. 相似文献
13.
Binary vapor–liquid equilibrium data were measured for the carbon dioxide (CO2) + 2,2-dichloro-1,1,1-trifluoroethane (R123) system and the carbon dioxide (CO2) + 1-chloro-1,2,2,2-tetrafluoroethane (R124) system at temperature from 313.15 to 333.15 K. These experiments were carried out with a circulating-type apparatus with on-line gas chromatography. The experimental data were correlated well by Peng–Robinson equation of state using the Wong–Sandler mixing rules. 相似文献
14.
M. Maczka W. Paraguassu P.T.C. Freire F.E.A. Melo 《Journal of solid state chemistry》2004,177(6):2002-2006
A high-pressure Raman scattering study of the tungstate Al2(WO4)3 is presented. This study showed the onset of two reversible phase transitions at 0.28±0.07 and 2.8±0.1 GPa. The pressure evolution of Raman bands provides strong evidences that both the transitions involve rotations/tilts of nearly rigid tungstate tetrahedra and that the structure of the stable phase in the 0.28-2.8 GPa range may be the same as the structure of the ambient pressure, low-temperature monoclinic (C2h5) ferroelastic phase of Al2(WO4)3. 相似文献
15.
V.N. Naumov M.A. Bespyatov T.V. Basova P.A. Stabnikov I.K. Igumenov 《Thermochimica Acta》2006,443(2):137-140
The heat capacity of Cr(C5H7O2)3 has been measured by the adiabatic method within the temperature range 5-320 K. An anomaly with a maximum at ∼60 K has been discovered which points to the phase transformation of the compound. Anomalous contributions to entropy and enthalpy have been revealed. The thermodynamic functions (entropy, enthalpy and reduced Gibbs energy) at 298.15 K have been calculated using the obtained experimental heat capacity data. The Raman spectra have been measured in the frequency range 60-400 cm−1 and in the temperature range 5-220 K. It has been discovered that a new line (109 cm−1) appears at ∼60 K. The nature of these peculiarities in heat capacity and in Raman spectra is discussed. 相似文献
16.
Molecular structure, ionic mobility and phase transitions in six- and seven-coordinated ammonium oxofluoroniobates (NH4)2NbOF5 and (NH4)3NbOF6 were studied by 19F, 1H NMR and DFT calculations. Equatorial fluorine atoms (Feq) in [NbOF5]2− and [NbOF6]3− are characterized by high 19F NMR chemical shifts while axial fluorine atoms (Fax) have those essentially lower. The high-temperature ionic mobility in (NH4)2NbOF5 does not stimulate the ligand exchange Feq ↔ Fax, whereas it is observed in (NH4)3NbOF6 as pseudorotation typical for seven-coordinated polyhedra. The transformation of pentagonal bipyramidal structure (BP) of [NbOF6]3− into capped trigonal prismatic (CTP) one takes place during the phase transition (PT) at 260 K. The PT of order-disorder type in (NH4)2NbOF5 is accompanied by transition of anionic sublattice to a rigid state. The 19F and 1H NMR data corroborate the independent motions of NH4 groups and anionic polyhedra in (NH4)2NbOF5 while they are coordinated in (NH4)3NbOF6. 相似文献
17.
S. V. Larionov L. A. Glinskaya T. G. Leonova R. F. Klevtsova 《Journal of Structural Chemistry》2005,46(6):1023-1030
Mixed-ligand complexes Cd(2,2′-Bipy)(i-PrOCS2)2 (I) and Cd(2,2′-Bipy)(i-BuOCS2)2 (II) have been prepared. Their structures were solved using the X-ray diffraction technique (X8 APEX diffractometer, MoK
α radiation, 1941 and 4244 F
hkl
, R = 0.0188 and 0.0379). The crystals are orthorhombic with unit cell parameters a = 18.1404(4) Å, b = 6.9513(1) Å, c = 17.5835(4) Å; V = 2217.27(8) Å3, Z = 4, space group Pccn (for complex I) and a = 11.7890(3) Å, b = 12.1859(3) Å, c = 17.5335(5) Å; V = 2518.9(1) Å3, Z = 4, space group P212121 (for complex II). The structures consist of isolated mononuclear molecules. The cadmium atoms have distorted octahedral N2S4 environments. Molecular packings and intermolecular interactions in the structures are considered.
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 6, pp.1064–1071, November–December, 2005.
Original Russian Text Copyright ? 2005 by S. V. Larionov, L. A. Glinskaya, T. G. Leonova, and R. F. Klevtsova 相似文献
18.
Panicker CY Varghese HT Philip D Nogueira HI Castkova K 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,67(5):1313-1320
Methyl(2-methyl-4,6-dinitrophenylsulfanyl)ethanoate was prepared by nucleophilic substitution. FT-IR and FT-Raman spectra of methyl(2-methyl-4,6-dinitrophenylsulfanyl)ethanoate were recorded and analyzed. Surface-enhanced Raman scattering (SERS) spectrum was recorded on a silver colloid. The vibrationl wavenumbers were computed by density functional theoretical (DFT) computations at the B3LYP/6-31G* level and they were found to be in good agreement with the experimental values. The molecule is adsorbed on the silver surface with the benzene ring in a 'tilted orientation'. 相似文献
19.
Annamma John Daizy Philip Keith R. Morgan S. Devanarayanan 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2000,56(14):386
The FT IR and FT Raman spectra of Co(en)3Al3P4O16 · 3H2O (compound I) and [NH4]3[Co(NH3)6]3[Al2(PO4)4]2 · 2H2O (compound II) are recorded and analysed based on the vibrations of Co(en)33+, Co(NH3)63+, NH4+, Al---O---P, PO3, PO2 and H2O. The observed splitting of bands indicate that the site symmetry and correlation field effects are appreciable in both the compounds. In compound I, the overtone of CH2 deformation Fermi resonates with its symmetric stretching vibration. The NH4 ion in compound II is not free to rotate in the crystalline lattice. Hydrogen bonding of different groups is also discussed. 相似文献
20.
James R. Durig Savitha S. Panikar Keith A. GlennYa Ying Zheng Gamil A. Guirgis 《Vibrational Spectroscopy》2011,55(2):250-257
Infrared and Raman spectra (3500-60 cm−1) of gas and/or liquid and solid 1-chloro-1-silacyclopentane (c-C4H8SiClH) have been recorded and the vibrational data indicate the presence of a single conformer with no symmetry which is consistent with the twisted form. Ab initio calculations with a variety of basis sets up to MP2(full)/aug-cc-pVTZ predict the envelope-axial and envelope-equatorial conformers are saddle points with nearly the same energies but much lower in energy than the planar conformer. Density functional theory calculations by the B3LYP method predicts slightly lower energies for the two envelope forms and considerably lower for the planar form. By utilizing the MP2(full)/6-31G(d) calculations the force constants, frequencies, infrared intensities, band contours, Raman activities, and depolarization values have been obtained to support the vibrational assignment. Estimated r0 structural parameters have been obtained from adjusted MP2(full)/6-311 + G(d, p) calculations. These experimental and theoretical results are compared to the corresponding quantities of some other five-membered rings. 相似文献