Vibrational spectra of lead(II) oxalate

The infrared and Raman spectra of anhydrous lead oxalate (PbC₂O₄) were recorded and discussed on the basis of its structural peculiarities. Some comparisons with other previously investigated metallic oxalates were made. Copyright © 2009 John Wiley & Sons, Ltd.     

Vibrational spectra of barium oxalate hemihydrate

The infrared and Raman spectra of barium oxalate hemihydrate, BaC₂O₄ · 0.5H₂O, were recorded and discussed on the basis of their structural peculiarities and in comparison with the spectra of the previously investigated calcium and strontium oxalates.     

Vibrational spectra of polaprezinc,a polymeric Zn(II) complex of carnosine

Polaprezinc, the Zn(II) complex of the dipeptide carnosine (β‐alanyl histidine) presents an interesting biological and pharmacological activity, specially as an anti‐ulcer agent. The infrared and Raman spectra of this compound were recorded and briefly discussed. Some comparisons were made with related complexes and with free carnosine. The results confirm the coordination environment of the Zn(II) cation, constituted by the terminal amino N‐atom, the deprotonated amide N‐atom and one carboxylate oxygen of one dipeptide molecule and the N‐atom of the imidazole moiety of a second carnosine molecule. Copyright © 2007 John Wiley & Sons, Ltd.     

Vibrational spectra of clioquinol and its Cu(II) complex

The infrared and Raman spectra of 5‐chloro‐7‐iodo‐8‐hydroxyquinoline (clioquinol, CQ) and that of its Cu(II) complex of stoichiometry [Cu(CQ)₂] were recorded and briefly discussed. Some comparisons were made with related complexes. The interest of the investigated systems in relation to Alzheimer's disease is briefly commented. Copyright © 2006 John Wiley & Sons, Ltd.     

The Vibrational Spectra of Complexes with Planar Monothiooxamides. IV. The Copper(II) and Copper(I) Complexes of Neutral Monothiooxamides

The new complexes CuX₂(LH₂), CuX₂ (SH₃) (X = Cl, Br), CuX(LH₂), CuX(SH₃) (X = Cl, Br, I), CuX(H₄MTO)₂ (X = Cl, Br), Cul(H₄MTO) and CuX(H₃MMTO)₂ (X = Cl, Br, I), where LH₂ = N.N′-dimethyl-monothiooxamide, SH₃ = N(s)-methylmonothiooxamide, H₄MTO = monothiooxamide and H₃MMTO = N_(o)-methylmonothiooxamide, have been prepared. The complexes were characterized by elemental analyses, conductivity measurements, magnetic moments and spectroscopic (UV/VIS, FT-IR, Laser-Raman) studies. The vibrational analysis of the complexes has been given using NH/ND, CH₃/CD₃ and ⁶³cu/⁶⁵cu isotopic substitutions. The neutral monothiooxamides behave as monodentate ligands in the Cu(I) complexes coordinating through their thioamide sulfur atom. The ligands LH2 and SH₃ act as bidentate chelating agents in the Cu(II) complexes with ligated atoms being the thioamide sulfur and the amide oxygen.     

Vibrational Studies of Palladium(II) Acetate Compounds Ii. Infrared Spectra of the Diethylamine Adduct of Palladium(II) Acetate

Recorded and discussed are the infrared spectra of the diethylamine adduct of palladium(II) acetate. An empirical assignment of the spectra is proposed. The palladium-oxygen bonds in the adduct are not much different in strength from those in hexa-μ-acetato-triangulo-tripalladium(II)-water (2/1). The diethylanine molecules are present as such, as evidenced by the appearance of a rather strong band attributed to the N-H stretching vibrations.     

The Vibrational Spectra of Complexes with Planar Monothiooxamides. III. The Palladium(II) Complexes of Neutral Monothiooxamides

The new complexes trans-[PdX₂(H₄MTO)2] (X = Cl, Br, I), trans-[PdX₂(H₃MMTO)2] (X = Cl, Br, I), trans-[PdX₂(SH₃)2] (X = Cl, Br), [Pd(H₄MTO)₄]CI₂ and [Pd(H₃MMTO)₄]CI₂, where H₄MTO = monothiooxamide, H₃MMTO = N(o)-methylmonothiooxamide and SH₃ = N(s)-methylmonothiooxamide, have been prepared. The complexes were characterized by elemental analyses, conductivity measurements, X-ray powder patterns, thermal methods and spectroscopic (UV/VIS, FT-IR, Laser-Raman) studies. The vibrational analysis of the complexes is given using NH/ND and CH₃/CD₃ isotopic substitutions. Monomeric square planar structures are assigned for the complexes in the solid state. The neutral monothiooxamides behave as monodentate ligands coordinating through their thioamide sulfur atom. The complex [Pd(SH2)2] was isolated during the thermal decomposition of trans-[PdCl₂(SH₃)₂].     

Vibrational Spectra and Normal Coordinate Analysis of Diamminediiodidezinc(II) with 15N and 2H Isotopic Substitution.

The Raman and IR. spectra of solid diamminediiodidezinc (II) with ¹⁵N and ²H isotopic substitution have been measured. The spectra have been interpreted assuming C_2v symmetry for the Zn(NH₃)₂I₂ complex structure. The skeletal stretching metal-ligand modes v_s(ZnN), v_as(ZnN), v_s(ZnI), v_as(ZnI) as well as the three bending modes δ(NZnN), δ(IZnI) and δ(IZnN) were assigned by comparison with the spectra of Zn(NH₃)₂C1₂ and Zn(NH₃)₂Br₂, and by the observed isotopic shifts of the frequencies. A normal coordinate analysis for the whole complex was carried out using the Local Symmetry Force Field Model.     

Vibrational Spectroscopic Studies of 3,4-Lutidine Metal (II) Tetracyanonickelate Complexes

Infrared and Raman spectra of seven new metal (II) 3,4-lutidine tetracyanonickelate complexes, M(3,4 L)₂ Ni(CN)₄ [where 3,4 L = 3,4 - dimethyl-pyridine or 3,4-lutidine; M = Mn, Fe, Co, Zn, Ni, Cu or Cd] (abbreviated to M - Ni - 3,4 L) have been investigated. Spectroscopic and magnetic susceptibility measurements indicate that the compounds have the structure of Hofmann-type complexes. The copper complex has spectral features different from the other compounds.     

Vibrational spectroscopic and force field studies of copper(II) chloride and bromide compounds,and crystal structure of KCuBr3

Vibrational spectroscopic and force field studies have been performed of 15 related copper(II) chloride and copper(II) bromide compounds, including hydrated salts crystallizing in ternary aqueous systems with alkali and ammonium halides. For halocuprates with distorted octahedral coordination characteristic stretching Raman wavenumbers, corresponding to symmetric stretching Cu^II X modes in the equatorial plane, were found in the ranges 247–288 cm⁻¹ for X = Cl, and 173–189 cm⁻¹ for X = Br, while the low‐wavenumber stretching modes for the weaker axial Cu X interactions varied considerably. The tetrahedral coordination for Cs₂CuCl₄ and Cs₂CuBr₄ leads to somewhat lower Cu X symmetric stretching wavenumbers, 295 and 173 cm⁻¹, respectively. The assignments of the copper–ligand stretching vibrations were performed with the aid of normal coordinate calculations. Correlations between force constants, averaged Cu X stretching wavenumbers and bond distances have been evaluated considering the following aspects: (1) Jahn–Teller tetragonal distortion (axial elongation) of the octahedral copper(II) coordination environment, (2) differences between terminal and bridging halide ligands (3) effects of coordinated water and the influence of outer‐sphere cations. Force constant ratios for terminal and bridging metal–halide bonds reveal characteristic differences between planar and tetrahedrally coordinated M₂X₆ species. In the hydrated copper(II) halide complexes, the halide ligands are more strongly bound than coordinated water molecules. The crystal structure of KCuBr₃ (K₂Cu₂Br₆), which was determined to provide structural information for the force field analyses, contains stacks of planar dimeric [Cu₂Br₆]²⁻ complexes held together by weak axial Cu Br interactions. Copyright © 2007 John Wiley & Sons, Ltd.     

An Infrared Spectroscopic Study of Crystalline Copper (II) Propionate and Butyrate

Abstract

Abstract: The vibrational spectra of crystalline anhydrous copper (II) propionate and butyrate were studied by FT-IR spectroscopy. A detailed assignment of the spectra of both compounds is presented and discussed. It is shown that the presence of two non-equivalent sets of carboxylate ligands within the crystals gives rise to several band splittings, which are particularly evident in those bands ascribable to normal modes involving predominantly the -C_βH₃ or -C_βH₂-fragments. In addition, the vibrational assignments made for the studied molecules are shown to be very useful to help understanding the much more complex spectra of long chain copper carboxylates.     

Vibrational Behavior of Transition Metal Cupferronato Complexes: Raman Studies on Cobalt(II) Cupferronato Derivatives

The FT-Raman spectrum of cupferron, [PhN₂O₂]NH₄ and the micro-Raman spectra of the new corresponding cobalt(II) cupferronato complexes, CoL₂A₂, L = PhN₂O₂, a = H₂O, MeOH, o-C₆H₄(NH₂)₂, p-C₆H₄(NH₂)₂ and CoL₂A, a = (-C₆H₄NH₂-p)₂ were recorded and discussed. All the complexes show a Raman band at about 1302 cm¹ and the characteristic v(N-N) and δ(ONNO) modes of the anionic ligand. the vibrational analysis of the title compounds reveals the electron delocalisation over the N-nitroso-N-hydroxylaminato (ONNO) unit, as well as the bidentate coordination of the cupferronato ligand to the metal center through the oxygen atoms.     

白云鄂博天然钕独居石的振动光谱研究(英文)

Raman, infrared and energy dispersive X-ray spectra of monazites have been measured and discussed. The result shows that the mineral is enriched in cerium, lanthanum,neodymium and praseodymium (Ce＞La＞Nd＞Pr)， The monazites have marked spectral characteristics, especially their v1, V3 Raman bands and v1, v4 infrared absorption bands. The characteristics can distinguish between monazite and other phosphate minerals. In addition, based on EDS and infrared absorption spectra, a small amount of fluoro-carbonate is found in the monazites.     

The hydrates and deuterates of ferrous sulfate (FeSO4): a Raman spectroscopic study

A comparative analysis has been carried out on the Raman spectra of FeSO₄·nH₂O (n = 1, 4, 7) including the ²D‐analogs. The effects of changing the degrees of hydration have been found from the lattice, SO₄²⁻ internal, and H₂O internal modes. Increasing degrees of hydration shift the intense ν₁(SO₄) peak to lower wavenumbers and reduce the amount of splitting on the ν₃(SO₄) peaks. Some of the water librational bands cause the broadening of the ν₄(SO₄) peaks in FeSO₄·7H₂O and the ν₂(SO₄) peaks in FeSO₄·7D₂O. The ν₂(H₂O) band in FeSO₄·H₂O is red‐shifted in excess of 100 cm⁻¹ relative to the unperturbed H₂O band. Between 240 and 190 K and between 140 and 90 K in the spectra of FeSO₄.4H₂O, two potential phase transitions have been identified from the changes in the lattice and water‐stretching regions. The resolution of the ν₁(H₂O) and ν₃(H₂O) bands in FeSO₄·4H₂O and FeSO₄·H₂O also improved sharply at low temperatures. The capability of distinguishing various forms of FeSO₄ hydrates unambiguously makes the Raman technique a potential analytical tool for the identification of sulfate minerals on planetary surfaces. Copyright © 2006 John Wiley & Sons, Ltd.     

Vibrational spectroscopic studies,conformations and ab initio calculations of 1,2‐bis(trifluorosilyl)ethane (SiF3CH2CH2SiF3)

Infrared spectra of 1,2‐bis(trifluorosilyl)ethane (SiF₃CH₂CH₂SiF₃) were obtained in the vapour and liquid phases, in argon matrices and in the solid phase. Raman spectra of the compound as a liquid were recorded at various temperatures between 293 and 270 K and spectra of an apparently crystalline solid were observed. The spectra revealed the existence of two conformers (anti and gauche) in the vapour, liquid and in the matrix. When the vapour was chock‐frozen on a cold finger at 78 K and annealed to 150 K, certain weak Raman bands vanished in the crystal. The vibrational spectra of the crystal demonstrated mutual exclusion between IR and Raman bands in accordance with C_2h symmetry. Intensity variations between 293 and 270 K of pairs of various Raman bands gave ΔH(gauche—anti) = 5.6 ± 0.5 kJ mol⁻¹ in the liquid, suggesting 85% anti and 15% gauche in equilibrium at room temperature. Annealing experiments indicate that the anti conformer also has a lower energy in the argon matrices, is the low‐energy conformer in the liquid and is also present in the crystal. The spectra of both conformers have been interpreted, and 34 anti and 17 gauche bands were tentatively identified. Ab initio and density functional theory (DFT) calculations were performed giving optimized geometries, infrared and Raman intensities and anharmonic vibrational frequencies for both conformers. The conformational energy difference derived in CBS‐QB3 and in G3 calculations was 5 kJ mol⁻¹. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis and Raman spectroscopic characterisation of the oxalate mineral wheatleyite Na2Cu2+(C2O4)2·2H2O

The mineral wheatleyite has been synthesised and characterised by Raman spectroscopy complimented with infrared spectroscopy. Two Raman bands at 1434 and 1470 cm⁻¹ are assigned to the ν_{(C O)} stretching mode and implies two independent oxalate anions. Two intense Raman bands observed at 904 and 860 cm⁻¹ are assigned to the ν(C C) stretching mode and support the concept of two non‐equivalent oxalate units in the wheatleyite structure. Two strong bands observed at 565 and 585 cm⁻¹ are assigned to the symmetric CCO in plane bending modes. The Raman band at 387 cm⁻¹ is attributed to the CuO stretching vibration and the bands at 127 and 173 cm⁻¹ to OCuO bending vibrations. A comparison is made with Raman spectra of selected natural oxalate bearing minerals. Oxalates are markers or indicators of environmental events. Oxalates are readily determined by Raman spectroscopy. Thus, deterioration of works of art, biogeochemical cycles, plant metal complexation, the presence of pigments and minerals formed in caves can be analysed. Copyright © 2008 John Wiley & Sons, Ltd.     

Laser Raman Spectra of Crystalline Chloromercurate(II) Complexes

Abstract

The laser Raman spectra of crystalline [(CH₃)₄N] HgCl₃ and [(CH₃)₄N]₂HgCl₄ have been studied in the 400–20 cm^?1 region. All expected Raman active modes for the HgCl₃ ^? and HgCl₄ ^?2 ions are observed and assignments of the vibrational frequencies are made in relation to the structure of the anions.     

Vibrational spectra of the layered monofluorophosphate (V), NH4Ag3(PO3F)2

The powder Fourier‐transform (FT) infrared (IR) and Raman spectra of the recently characterized NH₄Ag₃(PO₃F)₂ were recorded and are discussed with a site‐symmetry analysis based on its known structural data. Some comparisons are made with the solution spectra of the PO₃F²⁻ anion and with those of crystalline Ag₂PO₃F. Copyright © 2009 John Wiley & Sons, Ltd.