Nk. Petrov et al., METAL-ION DETECTION BY THE MAGNETIC-FIELD-SENSITIVE FLUORESCENCE OF INTRAMOLECULAR EXCIPLEXES CONTAINING AZA-CROWN-ETHER MOIETIES AS ELECTRON-DONOR, The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 101(38), 1997, pp. 7043-7046
Magnetic field effects (MFE) detected by intramolecular exciplex fluor
escence have been studied in acetonitrile solutions for new donor-acce
ptor compounds in which pyrene is Linked to aza-15-crown ether by a po
lymethylene chain with 3, 9, and 16 CH2 units. It was found that addit
ion of alkali and alkaline-earth ions to the solutions decreases the o
bservable MFE. The longer the chain and the greater the stability cons
tants of the aza-crown complexes with metal ions, the more pronounced
is the influence of the added metal ions. The data obtained are ration
alized on the basis of a kinetic scheme that specifically includes pho
toejection of metal ions from the crown-ether complexes, accompanied b
y Coulombic interaction of the ions released with the solvent-separate
d radical ion pairs, the so-called special salt effect.