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A Reversible Photoacid Switched by Different Wavelengths of Light
Author(s) -
Alghazwat Osamah,
Elgattar Adnan,
Alharithy Hajar,
Liao Yi
Publication year - 2021
Publication title -
chemphotochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 18
ISSN - 2367-0932
DOI - 10.1002/cptc.202000256
Subject(s) - photochemistry , irradiation , photostationary state , metastability , wavelength , proton , chemistry , relaxation (psychology) , thermal decomposition , materials science , isomerization , optoelectronics , organic chemistry , photoisomerization , catalysis , psychology , social psychology , physics , quantum mechanics , nuclear physics
Reversible photoacids have been widely used in different areas for control of proton‐driven processes with light. Previously reported reversible photoacids rely on thermal relaxation to return to the low‐acidity ground state. Herein we report a photoacid that can be switched between low‐acidity and high‐acidity states by different wavelengths of light. The photoacid can be converted into a high‐acidity metastable state by 470 nm irradiation. The thermal relaxation of the metastable state is very slow and its half‐life in DMSO is 55 h. Irradiation with 365 nm light quickly induced the reverse reaction and reached a photostationary state. UV/Vis absorption spectra of the forward and reverse processes induced by 470 nm and 365 nm irradiation, respectively, have well‐matched isosbestic points. No decomposition was observed after the photoacid was switched by the two wavelengths of light for many cycles. Reversible patterning with both writing and erasing steps performed with light was demonstrated using a polymer thin film containing the photoacid and chlorophenol red as the proton acceptor.