Colour polymorphism of a bis(quinoxaline) compound

Éva Csikós, György G. Ferenczy, János G. Ángyán, Zsolt Böcskei, Kálmán Simon, Csaba Gönczi, István Hermecz

Research output: Contribution to journalArticle

20 Citations (Scopus)


Synthesis of 2(1H)-quinoxalinone O-(2'-quinoxalinyl)oxime (3) results in two easily distinguishable crystal forms with different colours, providing a rare example of colour polymorphism. The crystal structures of the two forms have been determined and compared. Intermolecular interactions and light- absorption characteristics of the polymorphs have been analysed by a mixed quantum chemical/molecular mechanical method. In one of the polymorphic forms the crystal field stabilises relatively high energy conformations by enhanced electrostatic interactions. The difference in the light absorption is found to be caused partly by a conformational difference of the molecules. The crystal field increases the difference in the absorption wavelengths and shift them towards higher values.

Original languageEnglish
Pages (from-to)2119-2125
Number of pages7
JournalEuropean Journal of Organic Chemistry
Issue number9
Publication statusPublished - Sep 1 1999


  • Molecular mechanical calculations
  • Polymorphism
  • Quantum chemical calculations
  • Quinoxalines
  • X-ray analysis

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry

Fingerprint Dive into the research topics of 'Colour polymorphism of a bis(quinoxaline) compound'. Together they form a unique fingerprint.

  • Cite this

    Csikós, É., Ferenczy, G. G., Ángyán, J. G., Böcskei, Z., Simon, K., Gönczi, C., & Hermecz, I. (1999). Colour polymorphism of a bis(quinoxaline) compound. European Journal of Organic Chemistry, (9), 2119-2125.