The schiff base of gossypol with 3,6,9,12,15,18,21,24-octaoxa-pentacosylamine complexes and monovalent cations studied by electrospray ionization–mass spectrometry, 1H nuclear magnetic resonance, Fourier transform infrared, as well as PM5 semiempirical methods
✍ Scribed by Piotr Przybylski; Bogumil Brzezinski; Franz Bartl
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2004
- Tongue
- English
- Weight
- 483 KB
- Volume
- 74
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Abstract
A Schiff base of gossypol with 3,6,9,12,15,18,21,24‐octaoxa‐pentacosylamine (GSOB) forms stable complexes with monovalent cations. This process of complex formation was studied by electrospray ionization–mass spectrometry, ^1^H‐NMR and Fourier transform infrared spectroscopy as well as by the PM5 semiempirical method. It was found that GSOB forms 1:6 complexes with Li^+^ and Na^+^, and 1:4 complexes with K^+^ as well as 1:2 complexes with Rb^+^ or Cs^+^ cations and exists in all these complexes in the enamine–enamine tautomeric form. Moreover, within these complexes only Li^+^ cations can fluctuate between the oxygen atoms of the octaoxaalkyl chains. The interactions of Li^+^ cations with hydroxyl groups of the gossypol part is also possible. All other cations are much more localized. In the complex of GSOB with protons, a 1:2 stoichiometry is realized. The two protons are localized on the N atoms of the Schiff base, and the complex exists in the imine–imine tautomeric form. The structures of the complexes are calculated by PM5 semiempirical methods and discussed. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004