New Photochrome Probe Allows Simultaneous pH and Microviscosity Sensing

• Main Authors: Wu, Yuanyuan, Papper, Vladislav, Pokholenko, Oleksandr, Kharlanov, Vladimir, Zhou, Yubin, Steele, Terry W. J., Marks, Robert S.
• Other Authors: School of Materials Science & Engineering
• Format: Article
• Language: English
• Published: 2017
• Subjects: Stilbene; Maleamic acid
• Online Access: https://hdl.handle.net/10356/80665; http://hdl.handle.net/10220/42184
• Institution: Nanyang Technological University

4-N,N′-dimethylamino-4′-N′-stilbenemaleamic acid (DASMA), a unique molecular photochrome probe that exhibits solubility and retains trans-cis photoisomerisation in a wide range of organic solvents and aqueous pH environments, was prepared, purified and chemically characterised. Absorption, fluorescence excitation and emission spectra and constant-illumination fluorescence decay were measured in acetonitrile, dimethyl sulfoxide, ethanol, propylene carbonate, and aqueous glycerol mixtures. The pseudo-first-order fluorescence decay rates were found to be strongly dependent on the medium viscosity. In addition, the molecule exhibited the pH-dependent fluorescence and photoisomerisation kinetics.