Synthesis, Photochromism, and Effects of Metal Ions on Fluorescence of Dithienylethenes Containing Imidazo[2,1-a]isoquinoline

Abstract

Dithienylethene derivatives containing imidazo[2,1-a]isoquinolines were directly synthesized by treatment of the diketone with 2-ethynylbenzaldehyde in one pot. Their photochromism indicated that they can easily isomerize between the ring-open and ring-closed isomers upon irradiation with ultraviolet or visible light in CH₂Cl₂. At the same time, they display high selectivity toward Fe³⁺ by the fluorescence titration, such that the addition of Fe³⁺ can obviously suppress their fluorescence intensity.

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GRAPHICAL ABSTRACT

Keywords:

• Dithienylethene
• effects of metal ions
• imidazo[2,1-a]isoquinoline
• photochromism

ACKNOWLEDGMENTS

The authors acknowledge financial support from the National Natural Science Foundation of China (Nos. 2072039, 20931006, and 21072070) and the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0953).

Notes

^a Absorption maxima of ring-open isomers.

^b Absorption maxima of ring-closed isomer.

^c Quantum yields of ring-open (ϕ _c-o) and ring-closed isomers (ϕ _o-c).

^d Fluorescence quantum yields of 1–3 before UV irradiation.