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1 H NMR, FT‐IR and MS studies and PM5 semiempirical calculations of complexes between the Schiff base of gossypol with 2‐(aminomethyl)‐15‐crown‐5 and Ca 2+ , Pb 2+ and Ba 2+ cations
Author(s) -
Przybylski Piotr,
Schroeder Grzegorz,
Brzezinski Bogumil,
Bartl Franz
Publication year - 2003
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.614
Subject(s) - chemistry , gossypol , schiff base , tautomer , electrospray ionization , enamine , medicinal chemistry , stereochemistry , mass spectrometry , nuclear magnetic resonance spectroscopy , organic chemistry , catalysis , biochemistry , chromatography
A new Schiff base of gossypol with2‐(aminomethyl)‐15‐crown‐5 (GSCB) was shown to be capable of complexation with Ca 2+ , Ba 2+ and Pb 2+ cations. This process of complex formation was studied by electrospray ionization mass spectrometry, 1 H NMR and FT‐IR spectroscopy and by the PM5 semiempirical method. It was found that gossypol Schiff base can form a 1:2 complex with Ca 2+ , 1:1 or 1:2 complexes with Pb 2+ and only a 1:1 complex with Ba 2+ cation. In all complexes the Schiff base of gossypol exists as an enamine–enamine tautomer. The cations are coordinated through oxygen atoms from the crown part, lone pairs at the N‐atoms and O‐atoms of the O 1 H(O 1′ H) hydroxyl groups. The structures of these complexes were calculated by the PM5 semiempirical method and are discussed. Copyright © 2003 John Wiley & Sons, Ltd.