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111.
M.Tahir Güllüo?lu?enay Yurdakul 《Journal of Molecular Structure》2002,641(1):93-100
New Hofmann-type complexes and clathrates of the forms M(piperidine)2Ni(CN)4 and M(piperidine)2Ni(CN)4·1.5G (M=Cd, Co, Ni or Cu; G=benzene) were prepared in powder form and their infrared and Raman spectra are reported. The spectral features suggest that these compounds are similar in structure to the Hofmann-type clathrates except for the copper compounds. The complex and clathrate of Cu have different spectral features in comparison with its analogues due to the Jahn-Teller effect. 相似文献
112.
Sambhu Bhadra 《European Polymer Journal》2007,43(10):4332-4343
In situ synthesis of polyaniline (PAni) coated pyrogenic or fumed silica (PCFS) and precipitated silica (PCPS) were carried out by the oxidative polymerization of aniline in presence of fumed silica (FS) and precipitated silica (PS). Both uncoated and PAni coated silica fillers were characterized through scanning electron microscope (SEM), infrared spectroscopy and thermo-gravimetric analysis (TGA) to evaluate particle morphology and physico-chemical character of coated and uncoated silica particles. Semi-conducting composites made from two different types of PAni coated silica fillers with NBR exhibit different trend in the variation of electrical properties under different temperature and pressure. These differences in electrical properties of two types of composites are mainly due to physico-chemical characteristics of filler particles as well as their distribution in the polymer matrix. This type of composites may be used as semi-conducting and ESD (electrostatic discharge) material. 相似文献
113.
The vibrational frequencies of the N–H stretching modes of aniline after forming a strong doubly H-bonded complex with tetrahydrofuran (THF) are measured with infrared depletion spectroscopy that uses cluster-size-selective resonance-enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry. Two strong infrared absorption features observed at 3355 and 3488 cm−1 are assigned to the symmetric and antisymmetric N–H stretching vibrations of the 1:2 aniline–THF complex, respectively. The red-shifts of the N–H stretching vibrations of aniline agree with the ab initio calculated (MP2/6-31G**) aniline-(THF)2 structure in which both aniline N–H bonds interact with the oxygen atom of THF through two hydrogen bonds. The calculated binding energy is found to be 29.6 kJ mol−1 after corrections for basis set superposition error (BSSE) and zero-point energy. The calculated structure revealed that the angle between the N–H bonds in the NH2 group increased to 112.5° in the aniline–(THF)2 complex from that of 109.8° in the aniline. The electronic 0–0 band origin for the S1 ← S0 transition is observed at 32,900 cm−1 in the aniline–(THF)2 complex, giving a red-shift of 1129 cm−1 from that of the aniline molecule. 相似文献
114.
11 and 12 molar reactions of dioxouranium(VI) acetate dihydrate with the monobasic bidentateSchiff bases,o-HOC6H4CH=NR oro-HOC10H6CH=NR (R=C2H5,n-C3H7,n-C4H9 or C6H5) and bibasic tridentateSchiff bases,o-HOC6H4CH=NR(OH) oro-HOC10H6CH=NR(OH) (R=–CH2CH(CH3)- or —CH2CH2CH2–) have been studied and derivates of the type UO2(OAc)2(SBH), UO2(OAc)2(SBH)2, UO2(OAc)2(SBH
2) and UO2(OAc)2(SBH
2)2 (whereSBH andSBH
2 represent monobasic bidentate and bibasic tridentateSchiff base molecules respectively) have been isolated. These have been characterized by elemental analysis, conductance measurements and IR spectral studies.
UO2 2+-Komplexe von Schiff-Basen. VII. Uranylacetat-Komplexe mit monobasischen zweizähnigen und bibasischen dreizähnigen Schiff-Basen
Zusammenfassung Es wurden in 1:1- und 1:2-molaren Reaktionen von UO2(OAc)2·2H2O mitSchiff-Basen (L) Komplexe des Typs UO2(OAc)2 L bzw. UO2(OAc)2 L 2 isoliert. Die Komplexe wurden mittels Elementaranalyse, Leitfähigkeitsmessungen und IR-Spektren untersucht.相似文献
115.
D. Mihrin Dr. P. W. Jakobsen A. Voute Dr. L. Manceron Prof. R. Wugt Larsen 《Chemphyschem》2019,20(23):3238-3244
The high-resolution infrared absorption spectrum of the donor bending fundamental band ν of the homodimer (HCN)2 has been collected by long-path static gas-phase Fourier transform spectroscopy at 207 K employing the highly brilliant 2.75 GeV electron storage ring source at Synchrotron SOLEIL. The rovibrational structure of the ν transition has the typical appearance of a perpendicular type band associated with a Σ–Π transition for a linear polyatomic molecule. The total number of 100 assigned transitions are fitted employing a standard semi-rigid linear molecule Hamiltonian, providing the band origin ν0 of 779.05182(50) cm−1 together with spectroscopic parameters for the degenerate excited state. This band origin, blue-shifted by 67.15 cm−1 relative to the HCN monomer, provides the final significant contribution to the change of intra-molecular vibrational zero-point energy upon HCN dimerization. The combination with the vibrational zero-point energy contribution determined recently for the class of large-amplitude inter-molecular fundamental transitions then enables a complete determination of the total change of vibrational zero-point energy of 3.35±0.30 kJ mol−1. The new spectroscopic findings together with previously reported benchmark CCSDT(Q)/CBS electronic energies [Hoobler et al. ChemPhysChem. 19 , 3257–3265 (2018)] provide the best semi-experimental estimate of 16.48±0.30 kJ mol−1 for the dissociation energy D0 of this prototypical homodimer. 相似文献
116.
Analysis of alpha-amino acids, proteins, and phenolic compounds was simultaneously performed using three capillaries in capillary electrophoresis with chemiluminescence detection, taking advantage of the micro-space area for reaction/detection at the tip of the capillary. The three capillaries included usual, polymer-containing, and sodium docley sulfate (SDS)-containing migration buffers for separation. The eluted samples from the capillaries, which were inserted into the chemiluminescence detection cell, were mixed with chemiluminescence reagent at the tips of the capillaries to generate visible light. The specific micro-space area for reaction/detection at the tips of the capillaries enabled the simultaneous operation of the three separation modes in the present system. 相似文献
117.
Stephen Bell Xiaodong Zhu Gamil A. Guirgis James R. Durig 《Journal of Molecular Structure》2002,616(1-3):135-158
The infrared spectra (3500–50 cm−1) of the gas and solid and the Raman spectra (3500–50 cm−1) of the liquid and solid have been recorded for 2-hexyne, CH3–CC–CH2CH2CH3. Variable temperature studies of the infrared spectrum (3500–400 cm−1) of 2-hexyne dissolved in liquid krypton have also been recorded. Utilizing four anti/gauche conformer pairs, the anti(trans) conformer is found to be the lower energy form with an enthalpy difference of 74±8 cm−1 (0.88±0.10 kJ/mol) determined from krypton solutions over the temperature range −105 to −150 °C. At room temperature it is estimated that there is 42% of the anti conformer present. Equilibrium geometries and energies of the two conformers have been determined by ab initio (HF and MP2) and hybrid DFT (B3LYP) methods using a number of basis sets. Only the HF and DFT methods predict the anti conformer as the more stable form as found experimentally. A vibrational assignment is proposed based on the force constants, relative intensities, depolarization ratios from the ab initio and DFT calculations and on rotational band contours obtained using the calculated equilibrium geometries. From calculated energies it is shown that the CH3 group exhibits almost completely free rotation which is in agreement with the observation of sub-band structure for the degenerate methyl vibrations from which values of the Coriolis coupling constants, ζ, have been determined. The results are compared to similar properties of some corresponding molecules. 相似文献
118.
In this paper, the levels and the torsional microstates of hydrogen peroxide are determined from fully optimized ab initio calculations using a nuclear model in one dimension. Calculations have been performed at the MP2 level with the 6-311 G(2df,2pd), 6-31 1+G(2df,2pd), cc-pVTZ and AUG-cc-pVTZ basis sets including polarization orbitals and diffuse functions. The most stable conformation, calculated with the MP2/AUG-cc-pVTZ approach, is a trans–gauche conformer lying at 67.5° from the trans structure. By using the same level of calculations, the heights of the trans and cis barriers have been determined to be 386.5 and 2643.8 cm−1 in a good agreement with the experimental data. The variational torsional levels split into four components by the tunnelling effect of the barriers. The splitting of the fundamental level caused by the trans barrier has been found to be 11.8683 cm−1, whereas the splitting caused by the cis barrier is insignificant under n=2. Current ab initio energies confirm the experimental assignments and verify the separability of the torsion from the rest of the vibrations. However, the experimental relation of dependence on the torsion of the rotational constants cannot be reproduced in one-dimension and depends on several additional vibrational effects. 相似文献
119.
Samples of orthoferrites La1−xCaxFeO3 (0.15≤x≤0.45) were synthesized by double sintering ceramic technique. X-ray diffraction and infrared spectroscopy experiments were carried out and discussed for the investigated samples. The data showed the formation of single-phase orthorhombic structure of space group Pbnm. The FTIR spectra were performed in the region (1200–200 cm−1). Four main absorption bands were present with some side bands and shoulders in the range (1200–400 cm−1). Another four bands were appeared in the range (400–200 cm−1). The positions, intensities and values of the absorptions bands vary depending on the Ca content in the samples. The first absorption band appeared at about 920 cm−1 was assigned to the La–O stretching vibration. 相似文献
120.
《Journal of Molecular Structure》2002,616(1-3):259-264
The molecular structure of the title complex [ZnBr2(C7H6N2)2] was investigated by X-ray diffraction and IR spectroscopy methods. Molecules of zinc(II) complex crystallize in the triclinic crystal system with cell constants a=7.526(2) Å, b=7.8971(8) Å, c=13.431(1) Å, Z=2 and V=791.3(2) Å3. In the molecular structure, the Zn atom is coordinated tetrahedrally by two Br− anions and two benzimidazole ligands. Intramolecular steric repulsions between Br− anions and benzimidazole groups have been caused to cis configuration around the central metal atom. 相似文献