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Schiff base of gossypol with 3,6,9‐trioxa‐decylamine complexes with monovalent cations studied by mass spectrometry, 1 H‐NMR, FTIR, and PM5 semiempirical methods
Author(s) -
Przybylski Piotr,
Ilkevych Nataliya,
Schroeder Grzegorz,
Brzezinski Bogumil,
Bartl Franz
Publication year - 2004
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.10553
Subject(s) - chemistry , tautomer , schiff base , imine , alkyl , electrospray ionization , mass spectrometry , gossypol , medicinal chemistry , crystallography , organic chemistry , chromatography , catalysis , biochemistry
Abstract A new Schiff base of gossypol with 3,6,9‐trioxa‐decylamine (GSTB) forms stable complexes with monovalent cations. This process of complex formation was studied by electrospray ionization mass spectrometry, 1 H‐NMR and FTIR spectroscopy, and the PM5 (parametric method 5) semiempirical method. It is found that GSTB forms 1 : 1 and 1 : 2 complexes with Li + and Na + and 1 : 1 complexes with K + , 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 trioxaalkyl chains. All other cations are strongly localized. In the complex of GSTB with two protons localized on the N atoms of the Schiff base, the imine–imine tautomeric form is realized. The complexes of the Schiff base with K + , Rb + , or Cs + cations are the 1 : 1 type with the oxygen atoms of the trioxaalkyl chains, as well as the O 1 H or O 1′ H group coordinating the cation. The structures of the complexes are calculated by the PM5 semiempirical method and discussed. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004