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, (1)H nuclear magnetic resonance, Fourier transform infrared, as well as PM5 semiempirical methods.
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.
Przybylski
Piotr
P
Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland.
Brzezinski
Bogumil
B
Bartl
Franz
F
D002414:Cations, Monovalent / Q000737:chemistry; D002586:Cesium; D006072:Gossypol / Q000031:analogs & derivatives / Q000737:chemistry*; D008094:Lithium; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation; D011188:Potassium; D012413:Rubidium; D012545:Schiff Bases / Q000737:chemistry*; D012964:Sodium; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
C488501:3,6,9,12,15,18,21,24-octaoxa-pentacosylamine; D002414:Cations, Monovalent; D012545:Schiff Bases; D002586:Cesium; D008094:Lithium; D012964:Sodium; D006072:Gossypol; D012413:Rubidium; D011188:Potassium