1H- and 13C-NMR, FTIR, UV-VIS, ESI-MS, and PM5 studies as well as emission properties of a new Schiff base of gossypol with 5-methoxytryptamine and a new hydrazone of gossypol with dansylhydrazine.
A new Schiff base of gossypol with 5-methoxytryptamine (GSTR) and a new hydrazone of gossypol with dansylhydrazine (GHDH) have been synthesized and studied by Fourier transform infrared (FTIR), 1H and 13C nuclear magnetic resonance (NMR), ultraviolet-visible (UV-VIS), electrospray ionization-mass spectroscopy (ESI-MS) as well as the parametric method PM5. The spectroscopic methods have provided clear evidence that GSTR exists in chloroform solution as an enamine-enamine tautomer, whereas GHDH is present in chloroform as a N-imine-N-imine tautomer. The fluorescence spectra of both compounds indicate that their quantum yield of fluorescence is increased by one or two orders of magnitude compared to that of pure gossypol. The ESI-MS spectra of the 1:1 mixtures of GSTR or GHDH with formic acid have demonstrated that both compounds exist as protonated monomers in the gas phase, whereas GHDH can also exist in a stable protonated dimeric structure. The structures of the stable tautomers are calculated and visualized using the PM5 semiempirical method. The intra- and intermolecular hydrogen bonds within these structures are discussed.
Przybylski
Piotr
P
Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland.
Bejcar
Grzegorz
G
Huczyński
Adam
A
Schroeder
Grzegorz
G
Brzezinski
Bogumił
B
Bartl
Franz
F
D008735:5-Methoxytryptamine / Q000737:chemistry; D003619:Dansyl Compounds / Q000737:chemistry; D006072:Gossypol / Q000737:chemistry*; D006834:Hydrazines / Q000737:chemistry; D006835:Hydrazones / Q000737:chemistry; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008432:Mathematical Computing; D008958:Models, Molecular; D015394:Molecular Structure; D012545:Schiff Bases / Q000138:chemical synthesis / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013816:Thermodynamics
D003619:Dansyl Compounds; D006834:Hydrazines; D006835:Hydrazones; D012545:Schiff Bases; C027913:dansyl hydrazine; D008735:5-Methoxytryptamine; D006072:Gossypol