Infrared Spectra of the Square Planar Rhodium(I) Complexes cis-[Rh(CO)2(pyridine) (X)] (X = Cl,Br): Isotopic Labelling Studies and Normal Coordinate Analysis

Abstract

The infrared spectra (4000 - 50 cm^?1) of the square planar rhodium(I) complexes cis-[Rh(CO)₂ (pyridine) (X)] (X = Cl, Br) and their isotopomers with pyridine-d ₅ and ¹³CO have been determined. Assignments are based on earlier studies on pyridine and its complexes and on the shifts in infrared bands which are caused by the isotopic substitutions employed. Normal coordinate analysis following the procedure of Becher and Mattes has been used to confirm the empirical assignments. The two v(RhC) bands are observed near 490 and 450 cm^?1. v(RhN) is found near 210 cm^?1 and v(RhX) occurs at 310 (X = Cl) and 235 (X = Br) cm^?1. At frequencies below 200 cm^?1, the bands are assigned to bending modes in the following sequence: δ (RhN) > δ (CRhC) > δ (RhCl) > γ (RhCl) > γ (RhN).     

Experimental and theoretical FT‐IR and FT‐Raman spectroscopic analysis of N1‐methyl‐2‐chloroaniline

In this work, the experimental and theoretical vibrational spectra of N1‐methyl‐2‐chloroaniline (C₇H₈NCl) were studied. FT‐IR and FT‐Raman spectra of the title molecule in the liquid phase were 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 were calculated by using density functional method (B3LYP) with the 6‐311++G(d,p) basis set. The vibrational frequencies were calculated and scaled values were 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. ¹³C and ¹H NMR chemical shifts results were compared with the experimental values. The optimized geometric parameters (bond lengths and bond angles) were given and are in agreement with the corresponding experimental values of aniline and p‐methyl aniline. Copyright © 2008 John Wiley & Sons, Ltd.     

Infrared Spectra of the Copper(II), Nickel(II) and Palladium(II) Complexes of 4-amino-3-pentene-2-one

Abstract

The infrared spectra of the metal complexes of 4-amino-3-pentene-2-one were measured from 4000 - 20 cm^?1. The absorption bands were assigned by comparison to other similar molecules: The Cu(II) complex of 4-methylamino-3-pentene-2-one, and complexes of acetylacetone. Force constants for the molecules were calculated using the A_xsm matrix method. The spectra were measured at 298^oK and 77^oK.     

Vibration-rotation bands in ethane

The absorption spectrum of ethane was recorded at 0.014 cm^?1 resolution in the range 4500–6500 cm^?1 using a Fourier transform spectrometer and at room temperature. Eighteen bands could be identified and their type assigned. Upper state rotational constants are provided for the band at 5948.338 cm^?1 and Coriolis constants are obtained for most perpendicular bands. Vibrational assignments are suggested for the bands at 5948 cm^?1 (v7 + v10), 5914 cm^?1(v8 + v ₁₀+ v ₁₁), and 5852cm^?1 (v ₅+v ₁₀). All vibrational bands reported in the literature are gathered.     

Infrared and Raman Spectra of Sulfur-Nitride Complexes of Nickel(II) and Palladium(II)

Abstract

The infrared and Raman spectra of trans-Ni(S₂N₂CH₃)₂ and Pd(S₃N)₂ were measured from 4000-200 cm^?1. The absorption bands were assigned by comparison to the sulfur nitride complexes of nickel(II), palladium(II) and platinum(II). Normal coordinate analyses on these complexes were carried on these data using molecular parameters taken from X-ray data. To aid in band assignments, isotope shift data on trans-⁶²Ni(S₂N₂CH₃)₂ have also been carried out.     

Infrared Spectra of Morfolonium (mpH)2Mo2Cl6(H20)2(I),(mpH)2Mo2ClxBr6-x(H2O)2(II)/ (mpH)2Mo2Br6(H2O)2(III) and the Pyridinium (PyH)2Mo2I6(H2O)2(IV)Hexahalo-di(aquo): dimolybdate(II) Complexes,Containing Quadruple Metal-Metal Bounds

Abstract

The electronic (800–400 nm), infrared (4000–200,400–20 cm^?1), ordinary Raman (400–200 cm^?1) spectra of morpholinium and the pyridium hexahalo-di(aquo) dimolybdate(II) complexes, containing quadruple metal-metal bonds were investigated. The electronic spectra of the solid compounds at various temperatures (25,100 and 300K) demonstrate intense and structured bands in the visible region (510–582 nm) attributed to the expected δ→δ? transitions.

From the infrared and Raman spectra, the skeletal stretching modes in these complexes have been localized, and the charectenstic bands of these ions were observed in the expected regions.

Finally, the ionic interections were relatively weak, but the existance of phenomena was perceptible and the result was obtained in agreement with X-ray data.     

Infrared Spectra of Some Metal (II) Complexes of 2-Aminomethylpyridine

Abstract

Band assignments in the IR spectra (700–150 cm^?1) of [M(amp)₃] (ClO₄)₂ (amp = 2-aminomethylpyridine; M = Mn(II), Fe(II), Co(II), Ni(II), Zn(II), [Zn(amp)₂Cl₂] and [Pt(amp)Cl₂] derived from amp-ND₂, their unlabelled analogues, [Zn(amp)₂X₂] (X = Br, I) and [Pt(amp)Br₂] are discussed.     

Infrared Spectroscopic Study of Neyveli Lignite Samples from Mine Cut-I and II

Abstract

Infrared spectra of Neyveli Lignite samples at different depths from mine cut-I and II were recorded in the region 4000–200 cm^?1. Probable assignments of the bands were made with respect to the components present in the samples. The Lignite samples collected at 80m, 82m, 87m and 90m from minecut-I and 52m, 56m and 58m from minecut - II shows distinctly a band at 1500cm^?1 indicating that these belong to pleistocene—miocene period, while the absence of this band in the samples at deeper depths 92m and 94m from minecut-I and 62m and 65 m from minecut-II indicate that these belong to Oligocene to Palaeocene period.     

An Infrared Study of Conformational Isomerism in Cyclohexyl Iodide

Abstract

A comprehensive solvent, concentration, and temperature study has been made of the 850 to 400 cm^?1 region of the infrared spectrum of cyclohexyl iodide. This causes us to reject the assignment of Larnaudie and of Chiurdoglu and Reisse of v(C-I)_eq at 654 cm^?1 and v(C-I)^ax at 638 cm^?1, and to suggest that the two modes are almost coincident in n-hexane solution at 656.2 cm^?1 (eq) and 655.6 cm^?1 (ax).     

Contribution to the research on cellulose diacetate as a solid state track detector

Abstract

While having a similar composition to Cellulose Triacetate, Cellulose Diacetate is a less sensible heavy ions detector. With a 0.9 N potash etching at 20°C, ions which have higher Z than Carbon are not recorded and the Etch Rate Ratio is about 1 to 2 for Cu and Kr ions. The study of the infrared absorption spectra shows a decrease of the v(O-H) band intensity at 3500 cm^?1 for CDA, when it increases for CTA.     

The infrared spectrum of isothiazole in the range 600–1500 cm−1, including a high-resolution study of the v 11(A′) band at 818 cm−1 and the v 16(A″) band at 727 cm−1, together with ab initio studies of the full spectrum

Abstract

The gas-phase high-resolution infrared spectrum of isothiazole in the range 600–1500 cm^?1 has been recorded, and revised band centres obtained for a number of vibrations. An analysis of the v ₁₁(A′) band at 818 cm^?1 and the v ₁₆(A″) band at 727 cm^?1 has been performed, using the Watson Hamiltonian, A-reduction, III^r representation. These were combined with previous microwave spectral data to provide combined analyses for rotational constants and quartic centrifugal distortion constants Δ _J , Δ _JK , Δ _K , δ _j and δ _K . These extend the knowledge derived from previous microwave and IR spectral studies. The equilibrium structures and the derived harmonic frequencies were calculated by ab initio methods, using a variety of basis sets with MP2, MP4 and CCSD(T) methods, and a comparison of these with experimental data is discussed. At a pragmatic level, the closest correlation of the rotational constants with experiment is not obtained with the most sophisticated methodology. Similarly, the vibration frequencies and intensities also vary strongly with the procedure. In particular, we found that the cc-pVTZ+MP2 results probably provide the best numerical comparison with experimental IR data for this molecule.     

The Raman Spectrum of Mercury (II) Iodide in High Temperature Solvents

Abstract

The Raman spectrum of mercury(II) iodide was observed in cesium nitrate at 430°C and in meta- and para-terphenyl at 235 and 240°C, respectively. A single strong polarized line was found at 148. 5 cm^?1, width at half height 15 cm^?1 in cesium nitrate, and a single line at 154. 0 cm^?1 width at half height 7 cm^?1 in the terphenyls. The observed spectra are not consistent with interactions of the solute and the solvents involving bonds of highly covalent character, but do not exclude other interactions.

In the course of an investigation on the nature of mercury (II) iodide species in solution in molten alkali metal nitrates, by its distribution between the salt melts and terphenyl melts^{1, 2}, it became of interest to study by means of Raman spectroscopy the mercury (II) iodide species formed. Several such studies at lower temperatures have already been made: in the gas phase³, in a krypton matrix⁴, in alcohols⁵, tributy phosphate⁶ and dioxame⁷, and in molten mercury(II) iodide⁸, chloride⁹, and bromide⁹. The reason for looking at the Raman spectrum in yetfurther media was the suggestion made on the basis of thermodynamic and kinetic data^2,10 that the mercury(II) iodide species in the alkali mitrate melts are solvated by nitrate anions, and that possiby the mixed anion terrahedral species HgI₂(NO₃)₂ is formed. Recent Ranan sepctrophotometric data on mixed halide anionic complexes of mercury₁₁ identified prominent lines of the spectrum of the species HgBr_nI^2– _4–n, including HGBr₂I₂ ^2–, so that a comparison could be made. The solubility of mercury (II) iodide in molten alkali metal nitrates is rather small, expect for cesium nitrate¹², Where the solubility should be sufficent for the Raman spectrum to be recorded. Also, it was comcluded from vapor pressure osmometric data in aromatic solvents that demiric species of mercury(II) halides (even a trimeric species of the iodide) are found, in which the mercury has a distorted octahedral coordination, with three halogen atoms bonded to a mercury atom in the dimer¹³. In terphenyl melts, the solubility     

The effect of pressure on ftir spectra of ammonium halides

Abstract

FTIR spectra of NH₄Cl, NH₄Br and NH₄I have been measured in the range of 600 - 4800 cm^?1 at pressures up to 30 GPa at 135 K. The spectra show significant changes at the phase transition IV - V, particularly the splitting of v₄ in phase V is clearly demonstrated.     

Spectroscopic and E. P. R Studies of the Crystal and Molecular Structure of Cu(2-Benzoylpyridine)2(NO3)2.H2O

Abstract

Solid Cu(2-Benzoylpyridine)₂(NO₃)₂ has been studied by UV-Vis, IR, and EPR (X-band, Q-band) techniques. Monoclinic crystal symmetry was determined with two molecules per unit cell. Copper (II) is coordinated by two benzoylpyridine ligands and a single NO₃ group in the chromophore CuN₂O₃ of distorted trigonal bypiramidal stereochemistry. Exchange coupling values were determined from EPR spectra as |J| = 0.0026(2) cm^?1 between magnetically nonequivalent copper (II) sites, and |J| < O.3 cm^?1 between equivalent sites.

Results are discussed by a comparison with Cu(II)-benzoyl-pyridine complexes coordinated with azide N₃ ^? anions.     

Presence of Jahn-Teller distortions in a novel six-coordinate Ag(II) complex: temperature dependent EPR,optical and magnetic susceptibility measurements

Single-crystal variable temperature EPR, optical and polycrystalline magnetic susceptibility studies have been made on a novel six-coordinate Ag(II) complex. Temperature dependent EPR studies on pure single crystals of this compound reveal that dynamic Jahn-Teller distortion operates above 230 K, between 230 K and 120K static Jahn-Teller distortion sets in and below 110 K there is evidence of exchange interaction. Crystal g values were obtained by least-squares fitting with the data obtained from the orientation dependent EPR spectra of the undiluted single crystal of this complex at 300 K and 77 K. From an optical study the Jahn-Teller stabilization energy is found to be ～2250cm^?1. Comparison of Abs_max values for other silver(II) compounds enables us to conclude that the formal geometry of this complex is a tetragonally distorted octahedral. Infrared spectra of this complex were also recorded over a wide range of temperature. Magnetic susceptibility measurements over a wide range of temperature on the powder sample of this compound reveal that the complex is antiferromagnetically coupled in the temperature range 5–40 K with 2J = 0.906cm^?1, and above 40K it is ferromagnetically coupled with 2J = +7.4cm^?1. The effective magnetic moment (μ_eff) of this complex has been compared with that of a series of other silver(II) complexes available in the literature. Finally, the spectral and magnetic data of this complex have been compared with those of a corresponding isostructural and isomorphous copper(II) complex.     

The infrared spectrum of DCCF in the 320–850 cm−1 region: bending states up to υ4+υ5 = 3

Infrared spectra of deuterated monofluoroacetylene, DCCF, have been recorded in the region between 320 and 850 cm^?1 at an effective resolution ranging from 0.0024 to 0.0031 cm^?1. In total, 6650 rotation vibration transitions were assigned to 37 bands involving the bending states with v₄ + v₅ and |l₄+l₅|, respectively, up to 3, allowing the characterisation of the ground state and of 18 vibrationally excited states. The vν₅ bending fundamental has been studied for the first time. In addition, the difference band v₃ ← v₄ has been detected and analysed. All the assigned transitions have been fitted simultaneously by adopting a model Hamiltonian that takes into account the vibration and rotation l?type resonances. Rotational transitions in the ground and in bending excited states reported in the literature have been included in the global analysis. The set of 57 derived spectroscopic parameters reproduces 6130 infrared and 90 microwave and millimetre?wave transitions satisfactorily with root mean square values of 5.3 × 10^?4 cm^?1 and 77 kHz, respectively.     

Mössbauer and infrared studies of the Cu-Cr ferrites

Ferrites of the system CuCr_xFe_2–x O₄, wherex=0,0.2,0.4, 0.6 and 0.8, have been studied by Mössbauer and IR absorption spectra. Mössbauer spectra were recorded at room temperature. The spectra of all samples showed two well defined Zeeman patterns corresponding to A and B sites. The effect of the variation of chromium substitution on the various hyperfine interactions has been discussed. The cationic distribution makes clear that all Cr³⁺ ions occupy octahedral sites. The IR spectra in the range 200–4000 cm^–1 showed the presence of four bands. The high and low frequency bandsv ₁ andv ₂ belong to the tetrahedral and octahedral sites, respectively. Small bandsv ₃ andv ₄are observed around v₂ and are assigned to the octahedral divalent metal-oxygen ion complexes and the lattice vibrations of the system, respectively.     

High-resolution rovibrational analysis of vibrational states of A2 symmetry of the dideuterated methane CH2D2: the levels ν 5 and ν 7 + ν 9

The infrared spectrum of the CH₂D₂ molecule has been measured in the region 900–1500?cm^?1 on a Bomem DA002 Fourier transform spectrometer with a resolution of 0.0024?cm^?1 (FWHM, unapodized). Transitions belonging to the hot bands ν ₇?+?ν₉?ν ₇, ν₇?+?ν₉? ν ₉, ν₅?+?ν₇?ν₅, and ν₅?+?ν₉?ν₅ were extracted from the recorded spectra to determine the rovibrational energies of the A₂ symmetry vibrational states (v ₇?=?v ₉?=?1) at 2329.698?cm^?1 and (v ₅ ?=?1) at 1331.409?cm^?1. Vibrational energies as well as rotational and centrifugal distortion parameters of the (v ₇?=?v ₉=1) and (v ₅?=?1) states were determined that reproduce the experimental rovibrational energy levels of the (v ₇?=?v ₉?=?1) and (v ₅?=?1) vibrational states with a d _rms deviation of 0.0017 and 0.0006?cm^?1, respectively. The results are discussed in relation to the equilibrium structure of methane, which is redetermined here from the experimental data, and in relation to its potential hypersurface and anharmonic vibrational dynamics.     

The effect of resonance interactions on the absorption spectra of (SF6)2 dimers in low-temperature matrices: Calculations and experiment

The IR absorption spectra of (SF₆)₂ dimers in Ar and N₂ matrices are investigated at 11 K. As a result of the resonance dipole-dipole interaction, the band of the triply degenerate vibration v ₃ is split into two components v _{X, Y} and v _Z. In comparison with the gaseous state, the splitting Δv = v _{X, Y} ? v _Z in the argon matrix decreases to 18.45 cm^?1, whereas, in the nitrogen matrix, the band v _{X, Y} is split into components v _X and v _Y, with the splitting being equal to δ ≈ 0.9 cm^?1. A model that takes into account the influence of the matrix on the spectra of dimers is developed. The model makes it possible to successively (i) calculate the resonance spectrum of an isolated dimer in terms of the model of local modes taking into account resonance interactions, (ii) determine with the help of the Monte Carlo method the structure of a matrix consisting of 512–1440 Ar (or N₂) atoms and a rigid (SF₆)₂ dimer, and (iii) take into account interactions of local dipole moments of a dimer with particles of the matrix in the approximation of dipole-induced dipole interactions. The model developed satisfactorily describes the experimental results. The calculated frequencies v _Z, v _X, and v _Y of a dimer in the matrix are shifted toward smaller frequencies as compared to the gaseous state, while the resonance splitting decreases virtually by 2 cm^?1. It is shown that, in an argon matrix with a symmetric arrangement of argon atoms nearest to a dimer, the splitting of v _{X, Y} proves to be smaller than 0.05 cm^?1. In a nitrogen matrix, this splitting increases virtually to 0.4 cm^?1.