A spectroscopic study of the hydrogen bonding and pi-pi stacking interactions of harmane with quinoline.
A spectroscopic (UV-vis, Fourier transform IR, steady state, and time-resolved fluorescence) study of the interactions of the ground and excited singlet states of harmane (1-methyl-9H-pyrido/3,4-b/indole) with quinoline has been carried out in cyclohexane, toluene, and buffered pH=8.7 aqueous solutions. To analyze how the number of rings in the substrate influences these interactions, pyridine and phenanthridine have also been included in this study. In cyclohexane and toluene 1:1 stoichiometric hydrogen-bonded complexes are formed in both the ground and the excited singlet states. As the number of rings of the benzopyridines and the solvent polarity increase hydrogen-bonding interactions weaken and pi-pi van der Waals interactions become apparent.
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Departamento de Química Física, Facultad de Farmacia, Universidad de Sevilla, Spain.
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Muñoz
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D002021:Buffers; D003510:Cyclohexanes; D006247:Harmine / Q000031:analogs & derivatives* / Q000737:chemistry; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D015394:Molecular Structure; D011804:Quinolines / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D014050:Toluene
D002021:Buffers; D003510:Cyclohexanes; D011804:Quinolines; D014050:Toluene; D006247:Harmine; C005010:harman; C037219:quinoline