Photooxidation of tetrathiatetracene and tetraselenatetracene in halocarbon solutions: formation of new radical-cation salts

The photooxidation of tetrathiatetracene TTT and its selenium analogue TSeT to halocarbon solutions by visible and UV irradiation have been studied. This reaction leads to the formation of new chlorine, bromine, and iodine radical-cation salts which have been characterized.     

Resonance Raman spectra of n-methylthioacetamide

Rigorous resonance, as well as preresonance Raman spectra of N-methylthioacetamide and its N-deuterated compound are reported. The observed selectivity in the resonance intensity enhancement is discussed in relation to the potential energy distributions obtained by normal coordinate treatment. The structural change concerning the CN and CS bond lengths is suggested to accompany the π^* ← π electronic excitation.     

Resonance Raman spectra of tris(acetylacetonato)iron(III) and ruthenium(III) complexes and their solvent effect

The resonance Raman spectra of tris(acetylacetonatoiron(III)) and ruthenium(III) complexes in various solvents and in water-acetonitrile (W-AN) mixtures were measured. The resonance Raman spectra of both complexes indicated peaks near 460 and around 1580 cm^–1. Thev(C-O) peak (around 1580 cm^–1) is shifted to low frequency with an increase in the dielectric constant _T of the solvents, whereas thev(M-O) (M=Fe and Ru, near 460 cm^–1) are constant, independent of _T. It implies that the C-O bond in the acac^– ligand is lengthened by the polarizability effect of the solvents, while both the Fe-O and Ru-O bonds, which are located in the inside of the complexes, are not influenced by the solvents indicating that the interaction does not depend on the properties of individual solvent molecules but on those of the aggregate.     

Resonance raman spectra of meso-tetramethylporphine,meso-tetraethylporphine and their nickel complexes measured by using the sers technique

Surface-enhanced resonance Raman scattering spectroscopy was applied to measure the vibrational spectra of meso-tetramethylporphine (TMP), meso-tetraethylporphine (TEP), and their nickel complexes in layered structures having CaF₂/sample/Ag (structure I) and CaF₂/Ag/sample (structure II) configurations. The surface spectra clearly prove that, when the samples come into contact with Ag atoms (structure I) or a vacuum-deposited Ag film (structure II), they undergo chemical processes such as metal-incorporation and metal-exchange reactions, and a structural change.     

Far-infrared and Raman spectra ofpseudo-tetrahedral complexes of ethylenedimorpholene

Summary The far-i.r. and Raman spectra of a closely related group ofpseudo-tetrahedral complexes of general formula [MX₂EDM] are reported (M = Co^II, Ni^II, Cu^II, Zn^II; X = Cl or Br). EDM, ethylenedimorpholene, acts in these compounds as a bidentate nitrogen donor. The main skeletal vibrations are assigned under the approximate symmetry of theC _2v (MX₂Y₂) point group.     

Resonance Raman spectra of polyacetylene on zeolite and alumina surfaces

Raman spectra are reported for polyacetylene on exchanged zeolites and on alumina. The polymerization of acetylene on zeolites is found to depend on the zeolitic cation size and on surface coverage. Mean chain lengths of about fifteen CC bonds are formed on alumina.     

Resonance Raman spectra of electrons solvated in liquid alcohols

Resonance Raman spectra of electrons solvated in liquid methanol, ethanol, and n-propanol are presented. At least five distinct solvent modes exhibit resonantly enhanced scattering, including the OH torsion, CO/CC stretches, the OH in-plane bend, methyl deformations, and the OH stretch. The 200-350 cm-1 frequency downshift of the OH stretch indicates a strong H-bond interaction between the electron and the hydroxyl group. The multiple modes including alkyl vibrations that are coupled to the electronic transition of the solvated electron reveal the extension of the electron's wavefunction into the alkyl solvent environment.     

Raman and infrared spectra of methylmercury complexes of adenine

The i.r. and Raman spectra of four crystalline methylmercury complexes of adenine have been recorded. Three of these complexes, substituted or coordinated at positions N9, N7/N9, and N3/N7/N9, have well-characterized crystal structures. The last one is probably N6/N7/N9-metalated. The spectra of these complexes, as well as those of adenine, are compared in an attempt to establish correlations between these spectra and the sites of complexation in the derivatives.     

若干全氟环烃及其衍生物的拉曼光谱

由于C—F键的强极性,其振动模式在红外光谱中表现为强吸收谱带,而在拉曼光谱中则较弱,因此早期关于有机氟化合物振动光谱的研究以红外光谱为多,这方面Brown和Morgan已有详细总结.但有机氟化物的某些骨架振动往往呈现强的拉曼谱带.近年来对环状有机物的拉曼光谱研究已有较全面的总结,但对全氟环烷类及其衍生物尚无较系统的研究.本文报道若干全氟环烃及其衍生物的拉曼光谱数据,讨论了环呼吸振动频率与环大小及取代基的关系,环内双键振动频率的特性.实验证明全氟环烃的某些光谱特征与碳氢的环烃有较大的差异.     

Surface-enhanced Raman spectra study of metal complexes of N-D-glucosamine beta-naphthaldehyde and glycine and their interaction with DNA

Copper(II), zinc(II), cobalt(II) and cobalt(III) complexes of N-D-glucosamine beta-naphthaldehyde (C17H19O6N, NG) and glycine were synthesized. The four novel metal complexes, Cu(II)C19H28O11N2(CuGNG), Zn(II)C19H24O9N2 (ZnGNG), Co(II)C19H28O11N2(Co(II)GNG) and Co(III)C21H29O12N2(Co(III)GNG) were characterized by means of infrared (IR), electronic absorption spectroscopy and NMR etc. The surface-enhanced Raman spectra of the four complexes and their interaction with DNA were studied. By comparison of the surface-enhanced Raman spectra (SERS), the information of the four complexes' SER active sites and adsorption orientation were obtained. Combined with fluorescence spectra of Ethidium bromide (EthBr) DNA system, we concluded that none of the four complexes intercalate into DNA and that the presence of the glycine ligand lowered the anticancer activity of NG series complexes.     

Resonance Raman spectra and vibrational assignments of Azulene-d0 and Azulene-d8

The observed resonance effects in the Raman spectra of Azulene (C₁₀H₈) and its completely deuterated analog are utilized to assign the totally symmetric modes of these molecules. In conjunction with the data on the i.r. spectra and the normal coordinate analysis a complete assignment of the vibrational modes of these molecules is presented.The experimental excitation profiles are analyzed in the light of some current theoretical approaches. The experimental data strongly suggest that the variation of transition moment with the vibrational coordinate gives a dominant factor in determining the resonance Raman intensity of a mode.     

Raman spectra of amino acids and their aqueous solutions

Amino acids are the basic "building blocks" that combine to form proteins and play an important physiological role in all life-forms. Amino acids can be used as models for the examination of the importance of intermolecular bonding in life processes. Raman spectra serve to obtain information regarding molecular conformation, giving valuable insights into the topology of more complex molecules (peptides and proteins). In this paper, amino acids and their aqueous solution have been studied by Raman spectroscopy. Comparisons of certain values for these frequencies in amino acids and their aqueous solutions are given. Spectra of solids when compared to those of the solute in solution are invariably much more complex and almost always sharper. We present a collection of Raman spectra of 18 kinds of amino acids (L-alanine, L-arginine, L-aspartic acid, cystine, L-glutamic acid, L-glycine, L-histidine, L-isoluecine, L-leucine, L-lysine, L-phenylalanine, L-methionone, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine) and their aqueous solutions that can serve as references for the interpretation of Raman spectra of proteins and biological materials.     

Triiodolead(II) complexes. structure and Raman spectra

The crystals of tetramethylammonium triiodolead(II) are hexagonal with = 9.7823(11) A, c = 7.9167(8) A and γ = 120.0, Z = 2, space group P6₃/m. The structure was solved by direct methods and refined by least-squares techniques to a conventional R = 2.97% for the 312 independent reflections. The structure consists of chains of PbI₃ units running along the c axis. Each lead atom is octahedrally coordinated to six iodides with a Pb---I bond distance of 3.223 A. The tetramethylammonium cations sit in holes in the packing of the iodide ions. The cations are disordered.

The Raman spectra of salts of this species formed with several tetraalkylammonium cations are also reported and the bands tentatively assigned.