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  • 1
    Monograph available for loan
    Monograph available for loan
    Struktur und Bindung : Atome und Moleküle (1973)
    Leipzig : Dt. Verl. für Grundstoffindustrie
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    Call number: 9447
    In: Lehrwerk Chemie
    Type of Medium: Monograph available for loan
    Pages: 236 S. : graph. Darst.
    Edition: 2., durchges. Aufl.
    Series Statement: Lehrwerk Chemie Lehrbuch 1
    Location: Upper compact magazine
    Branch Library: GFZ Library
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  • 2
    Electronic Resource
    Electronic Resource
    1,2-Dithiete is more stable than 1,2-dithioglyoxal as evidenced by a combined experimental and theoretical IR spectroscopic approach (1989)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 111 (1989), S. 7651-7653 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00201a076
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  • 3
    Electronic Resource
    Electronic Resource
    Near-infrared absorbing dyes (1992)
    s.l. : American Chemical Society
    Chemical reviews 92 (1992), S. 1197-1226 
    Details
    ISSN: 1520-6890
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/cr00014a003
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  • 4
    Electronic Resource
    Electronic Resource
    The Origin of the Color of 1,2-Dithiins - Interpretation by Kohn-Sham Orbitals (2000)
    Springer
    Journal of molecular modeling 6 (2000), S. 177-185 
    Details
    ISSN: 0948-5023
    Keywords: Keywords 1,2-Dithiin, Molecular structure, Electron delocalization, Electronic transition, Time-dependent density-functional theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract According to calculations by time-dependent density-functional theory (TD-DFT) the wine-red color of the half-chair (C2) 1,2-dithiin (1) is mainly due to a one-electron transition between the frontier orbitals. These orbitals are characterized by local two-center CC π bonds. The symmetric HOMO of the twisted structure 1 correlates with the fully delocalized HOMO of the planar reference structure with C2v symmetry. The anti-symmetrical LUMO correlates both with the essentially localized σ* (SS) of the LUMO and the π* of the LUMO+1 of the planar compound. Thus the dominating one-electron transition of 1 has some π→σ* character in the terminology of the planar system with a strong admixture of the anti-bonding combination of the CC bond orbitals to the σ*-type LUMO. The color of 1,2-dithiins are unique because of the simultaneous presence of a non-coplanar C=C bond system and the SS bond. For the sake of comparison calculations were also performed at ab initio levels of theory (TD-RHF, SCI, EOM-CCSD and CASPT2). Although the absorption wavelengths are strongly underestimated by SCI and TD-RHF the order and the nature of the lowest-excited states are the same as those found by TD-DFT. The electron excitation of 1,2-dithiin is compared with that of 1,2-dithiane (3). In addition, the structure and the energetics of 1,2-dithiin are compared with 1,4-dithiin (4) and thiepin (5).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s0089400060177
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  • 5
    Electronic Resource
    Electronic Resource
    Semiempirical calculations on sulfur-containing heterocycles (1968)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 72 (1968), S. 3975-3985 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100858a007
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  • 6
    Electronic Resource
    Electronic Resource
    MO-LCAO-calculations on sulfur containing π-electron systems (1968)
    Springer
    Theoretical chemistry accounts 12 (1968), S. 200-205 
    Details
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Halbempirische SCF-CI-Berechnungen wurden auf Thiokohlensäurederivate ausgedehnt, um spezifische Eigenschaften intensiver Absorptionen im nahen UV zu erklären. Auch ohne besondere Anpassung der Parameter wurde gute Übereinstimmung mit experimentellen Daten erzielt. Die Änderungen der Elektronenverteilung bei der optischen Anregung sind komplizierter, als für die Thiokohlensäurederivate als gekreuzt konjugierte Systeme bisher angenommen wurde.
    Abstract: Résumé Des calculs SCF-CI semiempiriques sont étendus aux dérivés d'acide thiocarbonique en vue d'expliquer des propriétés spécifiques des absorptions intensives dans l'UV proche. Même sans ajustement des paramètres les résultats obtenus étaient en bon accord avec les dates experimentelles. Les changements de la distribution électronique par l'excitation optique sont plus compliques qu'on ne les estimait.
    Notes: Abstract Semiempirical SCF-CI-calculations were extended to derivatives of thiocarbonic acid to explain specific properties of intense near UV-absorptions. Good agreement with experimental data was obtained although parameters were not adjusted. The change of electron distribution by optical excitation is more complicated as has been assumed for thiocarbonic acid as crossed conjugated systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00528267
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  • 7
    Electronic Resource
    Electronic Resource
    Band structure of even and ions of odd polyenes (1977)
    Springer
    Theoretical chemistry accounts 46 (1977), S. 191-203 
    Details
    ISSN: 1432-2234
    Keywords: Polyenes, even, band structure of ∼ ; Polyenes, ions of odd, band structure of ∼
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The analysis of experimental data for singlet transitions (ΔE n) of even polyenes (I), cations (II) and anions (III) of odd polyenes show that for infinite chains ΔE ∞(I)/ΔE ∞(II)=ΔE ∞(I)/ΔE ∞(III) = 2:1. It is shown that the energy gap is equal for the three systems. In cases (II) and (III) there is a level (NBMO) in the gap which is vacant in (II) and occupied in (III). That is why the first optical transition in (II) and (III) depends on the semiwidth of the gap.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00578229
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  • 8
    Electronic Resource
    Electronic Resource
    Studies of the energy spectrum of α, ω- substituted polymethine chains. II. Polymethine chains with odd number of methine groups (1981)
    Springer
    Theoretical chemistry accounts 60 (1981), S. 185-200 
    Details
    ISSN: 1432-2234
    Keywords: Polymethines, α, ω- substituted ; Polymethines, energy spectrum of ∼
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The analysis of the experimental data for the energy of the longest wavelength optical transitions Δɛ n,opt of substituted polymethines X $$\dddot ---$$ (CH)2n+1 $$\dddot ---$$ X shows that in the asymptotic case (n→∞) Δɛ∞,opt does not tend to zero, as it follows from the empirically established correlations, but has a finite, non-zero value. It is shown that the energy gap of odd polymethines is the same as that of the even polymethines - the polyenes (ΔE ∞∼2 eV). The substituents (X ε N, O, B) are responsible for the appearance of levels in the gap. These, depending on the substituent character, are vacant (X ≡ B) or occupied (X ≡ N, O). The transition from or to such a level determines the longest wavelength optical transition energy of polymethines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00550335
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  • 9
    Electronic Resource
    Electronic Resource
    MO-LCAO Calculations of Polymethines (1975)
    Springer
    Theoretical chemistry accounts 36 (1975), S. 351-355 
    Details
    ISSN: 1432-2234
    Keywords: Polymethines ; Streptopolymethines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Idealized polymethines are defined as conjugated chain molecules with complete bond equilization and charge alternation. A constant π-bond order along the chain with N atoms has been derived for three types of polymethines which differ by the nature of the heteroatomic end groups. Corresponding to the number of π-electrons they are termined (N + 1)π-, Nπ- or (N − 1)π-polymethines. This classification embraces closed shell as well as open shell systems. The relations for the energy eigenvalues, coefficients and derived quantities have been obtained in closed form. The results for the different classes of polymethines are strongly related. Their molecular properties should be similar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00549699
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  • 10
    Electronic Resource
    Electronic Resource
    MO-LCAO-Berechnungen an schwefelhaltigen π-Elektronensystemen (1967)
    Springer
    Theoretical chemistry accounts 9 (1967), S. 140-150 
    Details
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mercaptobenzol wird als ein 8-Elektronensystem mit sieben Basisorbitalen nach einem SCF-CI-Verfahren in Pariser-Parr-Pople-NÄherung behandelt. Alle Einzentrenabsto\ungsintegrale werden gleichgesetzt (γ CC=γSS=10,84 eV) und die Zweizentrenabsto\ungsintegrale nach der Mataga-Nishimoto-Beziehung ermittelt. An Hand des UV-Absorptionsspektrums von Mercaptobenzol zwischen 155 und 300 mΜ werden für U S=21 eV und Β CS=0,5 Β CC empirisch abgeleitet. Die Berechnungen an Mercapto- und Methylmercaptobenzol erlauben neben einer Interpretation der UV-Spektren Aussagen über Ionisationseigenschaften und die Ladungsverteilungen, die in guter übereinstimmung mit dem Experiment stehen. Die Brauchbarkeit der vorgeschlagenen Parameter wird durch Berechnungen an 1,2-, 1,3- und 1,4-Dimercaptobenzol, 1- und 2-Mercaptonaphthalin und 9-Mercaptoanthracen nachgewiesen.
    Abstract: Résumé Mercaptobenzène est traité comme un système de 8 électrons avec sept orbitales de base dans une méthode SCF-CI en approximation PPP. Les valeurs de U S=21 eV et Β CS=0,5 Β CC sont obtenues à l'aide du spectre d'absorption U.V. Les calculs en Mercapto- et Méthylmercaptobenzene permettent aussi bien une interprétation des spectres U.V. comme des indications sur la ionisation et la distrubation de charge qui sont en bonne relation avec les experimentaux. Avec les paramètres proposés en recoit aussi pour 1,2,1,3-, 1,4- Dimercaptobenzène, 1- et 2-Mercaptonaphtaline et Mercaptoanthracène des résultats valables.
    Notes: Abstract Mercaptobenzene is treated as an 8-electron-system with seven basis orbitals according to an SCE-CI-method in the Pariser-Parr-Pople approximation. All of the one-center repulsion integrals were assumed to be the same (γ CC=γSS=10.84 eV) and the two-center repulsion integrals were determined according to the Mataga-Nishimoto-relation. Values of U s =21 eV and Β CS=0.5 Β CC were derived empirically from the UV-absorption spectrum of mercaptobenzene in the region 155–300 mΜ. The calculations on mercapto- and methylmercaptobenzene, besides allowing an interpretation of the UV-spectra, give predictions of ionization properties and charge distributions showing good agreement with experiment. The usefulness of the suggested parameters is shown with calculations on 1,2-, 1,3- and 1,4-dimercaptobenzene, 1- and 2-mercaptonaphthalene and 9-mercaptoanthracene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00529948
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