A spectroscopic study of the hydrogen bonding and π–π stacking interactions of harmane with quinoline

✍ Scribed by Manuel Balón; Pilar Guardado; María A. Muñoz; Carmen Carmona

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 288 KB
• Volume: 4
• Category: Article
• ISSN: 1075-4261
• DOI: 10.1002/(sici)1520-6343(1998)4:3<185::aid-bspy4>3.0.co;2-3

✦ Synopsis

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.