BEDT–TTF charge-transfer salts: new structures,new functionalities

In the continuing search for new physical properties and combinations of properties in molecular materials, novel phenomena and structures are identified in three categories of TTF and BEDT–TTF (bis-ethylenedithiotetrathiafulvalene) charge-transfer salts with inorganic complex anions. When the anion is a 3d complex containing NCS^– and an aromatic donor, long range π–d ferrimagnetic order is established by donor-anion π–π overlap; when the anion is a tris-oxalato-metallate(III) complex, both normal state and superconducting behaviour are dramatically influenced by changing guest molecules in the lattice, while incorporating columns of crown ether and H₃O⁺/H₂O leads to metallic conductors that simultaneously transport protons. To cite this article: P. Day, C. R. Chimie 6 (2003).     

The Raman spectra of the benzene—chlorine and benzene—bromine charge-transfer complexes

The Raman spectra of the “charge-transfer” complexes of benzene with chlorine and bromine in solutions have been recorded. The low-temperature Raman spectra of the crystalline compounds were also studied. The structure of the complexes and the interaction between the components have been discussed.     

SDAT implementation for the analysis of radioxenon β–γ coincidence spectra

The standard deconvolution analysis tool (SDAT) was developed for analysis of radioxenon β–γ coincidence spectra measured as part of the international monitoring system as defined in the comprehensive nuclear-test-ban treaty. The SDAT software analyzes each β–γ coincidence spectrum by fitting library vectors of each radionuclide of interest: ^131mXe, ^133mXe, ¹³³Xe, and ¹³⁵Xe. Detector background and radon are incorporated as optional components of the sample solution. Results are reported in mBq m^?3. A new graphical user interface has been developed to facilitate ease of use and improve the data visualization. Automated energy versus channel calibration algorithms were developed and implemented based on ¹³⁷Cs β–γ coincidence spectra. Details on the user tool and testing are included.     

The vibrational spectra of germane and silane derivatives—XII. A reassignment of the dimethylhalosilanes

The i.r. and Raman spectra of the dimethylhalosilanes, Me₂SiHZ and Me₂SiDX (X = F, Cl, Br, I) have been recorded and the fundamental vibrations assigned. Analysis of the spectra of the deuterated compounds indicate that existing assignments for Me₂SiHX are in error.     

Spectroscopic analysis of asymmetric top free radicals——Application to pure rotational spectra of NO_2 in the ground vibronic state

Several key problems involved in the analyses of spectra of asymmetric top molecules, i.e., the effective Hamiltonian, the representation and basis vector, identification of energy levels, the selection rules, the relative intensity, and Zeeman tuning rate, were elucidated systematically. Introducing the high-order centrifugal distortion terms into the effective Hamiltonian, the precision for calculation has been improved substantially, which allows us to analyze the high-lying rotational transitions. A global analysis of all available spectra of 14N16O2 in the ground vibronic state has been made to obtain a set of molecular constants of 14N16O2 in the ground vibronic state which is the most precise and extensive so far. Using the improved parameters, some FIR LMR lines left unassigned hitherto have been identified successfully.     

A vibrational analysis of the MnO 4 − bands

Teltow'S [14,15] measurements of the permanganate bands are reanalyzed using the level scheme of Ballhausen and Liehr [2]. For KMnO ₄ dissolved in KClO ₄ the components of the first ¹ T ₂ state are found at 18050 cm^–1 18078 cm^–1 and 18043 cm^–1. The breathing frequency of the MnO _– ⁴ unit is in this state 768 ^–1. The electronic origin of the second ¹ T ₂ state is found at 30723 cm^–1 with a breathing frequency of 760 cm^–1.Evidence is further found for a ¹ T ₁ state with its split components located at 14446 cm^–1, 14526 cm^–1 and 14600 cm^–1. The breathing frequency is here found to be 800 cm^–1.Finally for KMnO ₄ dissolved in NaClO ₄ there are indications that one or two spin-triplets are located near 13200 cm^–1.

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Zusammenfassung TeltowS Messungen des Permanganatspektrums [14, 15] werden mit Hilfe des Termschemas von Ballhausen und Liehr [2] von neuem analysiert. Für KMn ₄ in KClO ₄ findet man die zum ersten ¹ T ₂-Zustand gehörenden Komponenten bei 18050, 18078 und 18043 cm^–1. Die Valenzschwingung des MnO _– ⁴ liegt hier bei 768 cm^–1. Der Ursprung des zweiten ¹ T ₂-Systems wird bei 30723 cm^–1 gefunden, die dazugehörige Valenzfrequenz ist 760 cm^–1.Bei 14446, 14526 und 14600 cm^–1 liegen offenbar die Komponenten eines ¹ T ₁-Terms, wozu eine Valenzfrequenz von 800 cm^–1 gehört.Schließlich findet man für KMnO ₄ in NaClO ₄ Anzeichen für ein oder zwei Spin-Tripletts um 13200 cm^–1.

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Résumé Les bandes d'absorption du permanganate, mesurées par Teltow [14,15], sont réanalysées à l'aide d'un système de termes proposé par Ballhausen et Liehr [2]. Pour KMnO ₄ dans KClO ₄, on trouve les composants du premier état ¹ T ₁ à 18050, 18078 et 18043 cm^–1. La vibration symétrique du MnO _– ⁴ dans cet état se situe à 768 cm^–1. L'origine électronique du second état ¹ T ₂ est trouvé à 30723 cm^–1, la fréquence oscillatrice correspondante est de 760 cm^–1.Un état ¹ T ₁ avec ses composants à 14446, 14526 et 14600 cm^–1 est mis en évidence, avec une vibration symétrique de 800 cm^–1.Finalement, au cas du KMnO ₄ dissous dans le NaClO ₄, il y a des indications pour un ou deux triplets de spin vers 13200 cm^–1.

     

Potential energy surfaces and vibrational spectra for isotopomers of N_2O

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Unifit 2002—universal analysis software for photoelectron spectra

The current level of development of the spectra analysis software Unifit for Windows is presented and evaluated by checking with test spectra. The program is characterized and the correctness of the numerical routines is demonstrated for the particular cases of the Shirley type background model and the Gaussian-Lorentzian product model functions. Different approaches to an optimum fit result are suggested. A convenient analysis of the assessment of the peak fit procedure is proposed. All results are presented in tabular form too, to make the data more comprehensible.     

Some anomalies in the vibrational spectra of α, β-unsaturated ketones

Summary Some anomalies in the intensities of the bands of the C=C and C=O bonds in the vibrational spectra of , -unsaturated ketones have been explained by a difference in the sequence of the frequencies of the in-phase (_s) and out-of-phase (_as) vibrations of the multiple bonds in their cis (_s<_as) and trans (_s>_as) arrangements.     

“IR-Spectroscopy” — computer-program for the interpretation of infrared spectra

A computer-program "IR-Spectroscopy" for the interpretation of infrared spectra of organic compounds is described. It contains the following basic items for preprocessing and execution of the computer based interpretation process: handling of the rule-base CorTab, routines for automatic rule generation and interpretation modules on the basis of the programming languages PROLOG and C.     

Application of charge transfer reaction in the pharmaceutical analysis——Determination of chlorhexidine acetate

A spectrophotometric method for the determination of chlorhexidine acetate is described. The reaction between chlorhexidine acetate and chloranil took place in an alcohol-acetone solution at room temperature. The composition of the charge transfer complex is 1:2. Beer's law is obeyed in the concentration range of 15--270 μg·mL-1 with correlation coefficient 0.9995. The apparent molar absorptivity is 2.21×103 L·mol-1·cm-1 at 412 nm. The method is accurate (with a recovery of 100±1.6%) and precise (RSD=1.0%). It was successfully applied to determine chlorhexidine acetate in suppository or disinfectant solution.     

Normal coordinate analysis of porphin and its derivatives based on the solution of the inverse spectral problem for porphin and Cu porphin—III. Interpretation of vibrational spectra of metal complexes of octamethylporphin and octaethylporphin

The valence force field obtained for Cu porphin from the solution of the inverse spectral problem is used for calculating normal vibrations of Cu octamethylporphin and Cu octaethylporphin and their isotope-substituted derivatives (¹H-²H, ¹⁴N-¹⁵N). The interpretation of vibrational spectra of octamethylporphin and octaethylporphin metal complexes is given. Insufficient presentation of vibrational modes in terms of potential energy distribution to predict isotope shifts of vibrational frequencies is noted.     

Vibrational modes of the anthracene—tetrachlorophthalic anhydride charge-transfer complex

Raman and i.r. studies of the anthracene—tetrachlorophthalic anhydride charge-transfer complex have been carried out. Five lattice modes are identified in the low-frequency Raman spectra. The 21 cm⁻¹ lattice band is tentatively assigned to the librational vibration of the donor and acceptor molecules along their stacking axis. The intramolecular modes are assigned on the basis of the free-molecule symmetries D_2h and C_2ν for anthracene and tetrachlorophthalic anhydride, respectively. The intramolecular frequencies do not change significantly on complexation. This suggests that the molecular symmetry and the force constants between interacting molecules are not greatly affected by the formation of the complex.     

Application of the Todd–Atherton synthetic approach for chemical modification of tetraene macrolide antibiotic lucensomycin

Lucensomycin, tetraene macrolide antibiotic, has been chemically modified with dialkyl(diaryl) phosphites under conditions of the Todd–Atherton reaction. The reaction has yielded the corresponding dialkyl-(diaryl) amidophosphate derivatives of the antibiotic. Physico-chemical properties of the prepared derivatives as well as their toxicity and antifungal activity towards a series of pathogenic Candida yeast-like fungi have been studied. The automated decision-making information system for selection of highly efficient antibiotics has been described.