Theoretica chimica acta

, Volume 5, Issue 2, pp 102–111 | Cite as

The electronic structure of tetra-azapentalene

  • L. Paoloni
  • P. Gramaccioni
  • A. Vaciago


The ultraviolet absorption spectra in various solvents and a study of the electronic structure of 1, 3a, 4, 6a-tetra-azapentalene are reported. The ASMO-SCF-CI method in the Pariser-Parr-Pople approximation has been used with different alternatives for evaluating theγ pq and the (A: pp) integrals. Only two out of the six different set of calculations have given an acceptable prediction of the first π* ←π transition; moreover the introduction of penetration integrals is found necessary for a correct prediction of the sequence of the N-N bond lengths based on the sequence of the bond orders.


Physical Chemistry Inorganic Chemistry Organic Chemistry Absorption Spectrum Bond Length 
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Les spectres d'absorption ultraviolet dans des differents solvents et un étude sur la structure électronique du 1, 3a, 4, 6a-tetra-azapentalene sont exposés. La méthode ASMO-SCF-CI dans l'approximation de Pariser-Parr-Pople, a été employée avec plusieures alternatives pour 1e calcul des intégralesγ pq et (A: pp). Entre les six differents calculs accomplis, deux seulement ont donné une prédiction acceptable pour la prémière transitionπ* On a trouvé que pour une correcte prédiction de la séquence des longueures N-N sur la base des indices de liaison il faut introduir dans les calculs les integrales de pénetration.


Die UV-Absorptionsspektren von 1, 3a, 4, 6a-Tetraazapentalen in verschiedenen Lösungsmitteln werden angegeben. Die Elektronenstruktur dieser Verbindung wurde mittels SCF-CI-Rechnungen mit den Näherungen von Pariser-Parr-Pople and verschiedenen Sätzen vonγ pq und (A: pp)-Integralen ermittelt, wobei zwei der sechs Sätze einen annehmbaren π-π*-Über-gang liefern. Sollen sich die Werte der N-N-Bindungsordnungen in Übereinstimmung mit denentsprechenden Bindungslängen ergeben, so können die Durchdringungsintegrale nicht vernachlässigt werden.


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  1. [1]
    Brufani, M., W. Fedeli, G. Giacomello, andA. Vaciago: Chem. Ber.96, 1840 (1963).Google Scholar
  2. [2]
    [2]————, andA. Vaciago Gazz. chim. Ital.93, 1556, 1571 (1963); Ric. Sci.33 (II-A), 1237 (1963).Google Scholar
  3. [3]
    ---Pont. Acad. Scient. Commentarii, Vol. I, No. 34 (1963).Google Scholar
  4. [4]
    Burke, M. E., R. A. Sparks, andK. N. Trueblood: Acta Cryst.16, A-64 (1963) and private communication.Google Scholar
  5. [5]
    Carboni, R. A.: U.S. Patent 2, 904,544; C. A.54, 11062 (1960).Google Scholar
  6. [6]
    —; andJ. E. Castle: J. Am. chem. Soc.84, 2453 (1962).Google Scholar
  7. [7]
    Cignitti, M., andL. Paoloni: To be published.Google Scholar
  8. [8]
    Hinze, J., andH. H. Jaffa. J. Am. chem. Soc.84, 540 (1962).Google Scholar
  9. [9]
    Julg, A.: J. Chim. physique57, 19 (1960).Google Scholar
  10. [10]
    Metze, R.: Angew. Chem.68, 580 (1956).Google Scholar
  11. [11]
    Nishimoto, K., andN. Mataga: Z. physik. Chem. (Frankfurt)12, 335;13, 140 (1957).Google Scholar
  12. [12]
    Paoloni, L.: Nuovo Cim.4, 410 (1956).Google Scholar
  13. [13]
    — Gazz. chim. Ital.96, 83 (1966).Google Scholar
  14. [14]
    Parr, R. G.: Quantum theory of molecular electronic structure, Chap. III, IV. New York: Benjamin Inc. 1963.Google Scholar
  15. [15]
    Pfleger, R., F. Reinhardt, andH. G. Hahn: Angew. Chem.68, 680 (1956).Google Scholar
  16. [16]
    —, andH. G. Hahn. Chem. Ber.90, 2411 (1957).Google Scholar
  17. [17]
    —,E. Garthe, andK. Rauer: Chem. Ber.96, 1827 (1963).Google Scholar
  18. [18]
    Poole, M. D.: Thesis, p. 59–63. Oxford, 1964.Google Scholar
  19. [19]
    Scrocco, E., andO. Salvetti: Ric. Sci.23, 98 (1953).Google Scholar
  20. [20]
    Simonetta, M., V. Pierpaoli, andG. Favini: Rend. Accad. Lincei24, 58 (1958) ; Mol. Physics1, 181 (1958).Google Scholar

Copyright information

© Springer-Verlag 1966

Authors and Affiliations

  • L. Paoloni
    • 1
  • P. Gramaccioni
    • 2
  • A. Vaciago
    • 2
  1. 1.Laboratories of ChemistryIstituto Superiore di SanitàRome
  2. 2.Department of PhysicsCatholic University Medical SchoolRomeItaly

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