posted on 2024-02-23, 19:03authored byLilan Tan, Wenrong Cai, Fangqin Wang, Junyao Li, Datong Wu, Yong Kong
Electrochemiluminescence (ECL), integrating the characteristics
of electrochemistry and fluorescence, has the advantages of high sensitivity
and low background. However, only a few studies have been reported
for enantioselective sensing based on the ECL-active platform because
of the huge challenges in constructing tunable chiral ECL luminophores.
Here, we developed a facile strategy to design and prepare ECL-active
chiral covalent organic frameworks (COFs) Ph-triPy+-(R)-Ru(II) for enantioselective sensing. In such an artificial
structure, the ionic skeleton of COFs was beneficial to the electron
transfer on the working electrode surface and the chiral Ru-ligand
was used as the chiral ECL-active luminophore. It was found that Ph-triPy+-(R)-Ru(II) coupled with sodium persulfate
(Na2S2O8) as the coreactant exhibited
obvious ECL signals. More importantly, a clear difference toward l- and d-enantiomers was observed in the response of
the ECL intensity, resulting in a uniform recognition law. That is,
for amino alcohols, d-enantiomers (1 mM) measured by Ph-triPy+-(R)-Ru(II) showed a higher ECL intensity
compared with l-enantiomers. Differently, amino acids (1
mM) gave an inverse recognition phenomenon. The ECL intensity ratios
between l- and d-enantiomers (1 mM) are in the range
of 1.25–1.94 for serine, aspartic acid, glutamic acid, valine,
leucine, leucinol, and valinol. What is more interesting is that the
ECL intensity was closely related to the concentration of l-amino alcohols and d-amino acids, whereas their inverse
configurations remained unchanged. In a word, the present concept
demonstrates a feasible direction toward chiral ECL-active COFs and
their potential for efficient enantioselective sensing.