Thermal, FTIR and XRD study on some 1:1 molecular compounds of theophylline

J. Madarász, P. Bombicz, K. Jármi, M. Bán, G. Pokol, S. Gál

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Thermal stability and structural features of three newly synthesized 1:1 lattice compounds of theophylline (th) with ethylenediamine carbamate (enCO2), 1,10-phenanthroline (phen), and 5-sulfosalicylic acid (sa-5-SO3H) have been studied in comparison with those of the theophylline compounds with ethanolamine (ea) and salicylic acid (sa). Simultaneous TG-DTA measurements, FTIR spectroscopy and X-ray diffraction have been carried out to get information on the various structural units of these solid inclusions, especially on the actual form (molecule, anion or cation) of theophylline moieties built in. Theophyllinate and theophyllinium ions have been found in the ethanolammonium-theophyllinate (1:1) (1, eaH+·th-) and the theophyllinium salicyclic acid 5-sulfonate monohydrate (1:1:1), (5, thH+·saSO3-·H2O), respectively. Whilst the 1:1 complexes with 1,10-phenanthroline (2, th·phen), ethylenediamine carbamate (3, th·enCO2), and salicylic acid (4, th·sa) contain neural theophylline moieties associated with H-bonds. In compound (3) the zwitterion of N-(2-ammonium-ethyl)carbamate (NH3+-CH2-CH2-NH-CO2 -) is present.

Original languageEnglish
Pages (from-to)281-290
Number of pages10
JournalJournal of Thermal Analysis and Calorimetry
Volume69
Issue number1
DOIs
Publication statusPublished - Aug 26 2002

Keywords

  • 1,10-phenanthroline
  • Ethanolamine
  • Ethylenediamine carbamate
  • FTIR
  • Salicylic acid and 5-sulfosalicylic acid
  • Simultaneous TG-DTA
  • Theophylline lattice compounds
  • Unit cell parameters
  • XRD

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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