Nanojars are a class
of supramolecular coordination complexes based
on pyrazolate, Cu2+, and OH– ions that
self-assemble around highly hydrophilic anions and serve as efficient
anion binding and extraction agents. In this work, the synthesis,
characterization, and photophysical properties of pyrene-functionalized
fluorescent nanojars are presented. Three pyrene derivatives, 4-(pyren-1-yl)pyrazole
(HL1), 4-(5-(pyren-1-yl)pent-4-yn-1-yl)pyrazole (HL2), and 4-(3-(pyrazol-4-yl)propyl)-1-(pyren-1-yl)-1,2,3-triazole
(HL3), and the corresponding nanojars were synthesized
and characterized using nuclear magnetic resonance spectroscopy and
mass spectrometry. Electronic absorption, steady-state, and time-resolved
fluorescence measurements were carried out to understand the interaction
between the pyrene fluorophore and copper nanojars. Optical absorption
measurements have shown minor ground state interaction between the
fluorophore and nanojars. The fluorescence of pyrene is significantly
quenched when attached to nanojars, suggesting strong contribution
from the paramagnetic Cu2+ ions. Significant static quenching
is observed in the case of L1, when pyrene is directly
bound to the nanojar, whereas in the case of L2 and L3, when pyrene is attached to the nanojars using flexible
tethers, both static and dynamic quenching are observed.