Hydrogen bonding NH/pi interactions between betacarboline and methyl benzene derivatives.
In the presence of benzene, toluene, m-xylene, mesitylene and durene, the pyrrolic NH stretching band of betacarboline, 9H-pyrido[3,4-b]indole, and its 1-methyl derivative, harmane, in tetrachloroethane diminishes in intensity while a new red-shifted band grows up. The shifts of the associated bands increase linearly with the pi-electron density of the substrates. These spectral changes are attributed to the formation of 1:1 molecular association complexes between the betacarbolines and the benzenoid substrates. The complexes are stabilized by the hydrogen-bonding interaction between the pyrrolic NH group of betacarboline and the pi-delocalized electrons of the benzene derivatives. The influence of these NH/pi hydrogen-bonding interactions in the fluorescence spectra of betacarboline is discussed.
Muñoz
M A
MA
Departamento de Química Física, Facultad de Farmacia, Universidad de Sevilla, Spain.
Sama
O
O
Galán
M
M
Guardado
P
P
Carmona
C
C
Balón
M
M
D001554:Benzene / Q000737:chemistry*; D002243:Carbolines / Q000737:chemistry*; D006247:Harmine / Q000031:analogs & derivatives / Q000737:chemistry; D006860:Hydrogen Bonding; D008956:Models, Chemical; D012997:Solvents; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared
D002243:Carbolines; D012997:Solvents; D006247:Harmine; C005010:harman; D001554:Benzene