Pr. Bangal et S. Chakravorti, EXCITED-STATE DYNAMICS OF 4-PYRROLIDINO PYRIDINE IN DIFFERENT SOLVENTS, Journal of photochemistry and photobiology. A, Chemistry, 116(1), 1998, pp. 47-56
Photophysical properties of 4-Pyrrolidino Pyridine (PP) have been deli
neated from the absorption, steady state and time-resolved spectroscop
y in different solvents. Preferential hydrogen bonding of PP with wate
r and also protonation with acid at intercyclic (pyrrolidino) nitrogen
lone pair site could be observed. The intramolecular exciplex as pred
icted from semi-empirical calculations controls the photophysics in we
akly polar and nonpolar solvents. In water, a ground-state pretwisted
pyrrolidino group forms hydrogen-bonded complex that dominates over th
e intramolecular exciplex and this H-bonded exciplex acts as a quenchi
ng channel for the dual fluorescence. Intermolecular exciplexes of PP
were found to form in binary and ternary solutions with polar solvent
containing N-atom. Fluorescence in beta-cyclodextrin cavity resembles
intramolecular exciplex in ethanol with high quantum yield. (C) 1998 E
lsevier Science S.A. All rights reserved.