Using the title ionophore DNS-MAC(O-5) as the host, its cation recognition
properties for Li+, Na+, K+, Mg2+, Ba2+ and Pb2+ in acetonitrile and in aqu
eous solution were studied by fluorescence and NP-RTP method, respectively.
The corresponding stability constants and the recognition sensitive factor
s for the host-guest complexes were determined. The results proved that the
charge of guest cation and the spatial matching requirement between azacro
wn ring and the cation are the two most important factors on the recognitio
n process. DNS-MAC(O-5) undergoes obviously a spectral change upon binding
with cation. These changes are mainly controlled by the charge density of t
he cation. When the azacrown ether moiety of the ionophore was coordinated
with a cation, not only the dipole moment of the lumino-ionophore was incre
ased, but also it was more favorable for the photoinduced intramolecular ch
arge transfer, so the stability of exited state was increased and the fluor
escence spectrum was red shifted. At the same time, the relative fluorescen
ce quantum of DNS-MAC(O-5) in water and acetonitrile was determined by the
comparative method in this paper.