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A Deep‐Red to Near Infrared (NIR) Fluorescent Probe Based on a Sulfur‐Modified Rhodamine Derivative with Two Spirolactone Rings
Author(s) -
Tian Xinyu,
Liu Huawei,
Wei Fangfang,
Wang Xiangchuan,
Zhao Shunan,
Liu Chuangjun,
Tse Yu Chung,
Wong Keith ManChung
Publication year - 2020
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.202000384
Subject(s) - xanthene , fluorescence , chemistry , rhodamine , photochemistry , sulfur , derivative (finance) , organic chemistry , physics , quantum mechanics , financial economics , economics
We report the synthesis, characterization, and photophysical and ion‐binding properties of deep‐red to near‐infrared (NIR) fluorescent rhodamine derivatives, bearing two spirolactone rings and substitution of the oxygen atoms in the xanthene ring with sulfur atoms ( 1‐S ). The diastereoisomeric cis ‐ and trans ‐forms of the rhodamine derivative were separated and the cis ‐form ( cis ‐ 1‐S ) was structurally characterized by X‐ray crystallography. Upon treatment with Hg 2+ ion, cis ‐ 1‐S was converted into the dual spirolactone ring‐opened species, resulting in significant color change and fluorescence enhancement. Substitution of the oxygen atoms with sulfur and extended π‐conjugation across the fused six‐membered rings upon the two rings‐opening processes in the presence of Hg 2+ ion led to a significant red‐shift of absorption (623 nm) and fluorescence (706 nm) peaks, compared to the ordinary rhodamine. Furthermore, the intracellular Hg 2+ ‐sensing properties of the cis ‐ 1‐S have been studied by confocal microscopy.