title: New Photochrome Probe Allows Simultaneous pH and Microviscosity Sensing.
abstract: 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.
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Wu
authors.forename: Vladislav
authors.initials: V
authors.lastname: Papper
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Pokholenko
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kharlanov
authors.forename: Yubin
authors.initials: Y
authors.lastname: Zhou
authors.forename: Terry W J
authors.initials: TW
authors.lastname: Steele
authors.forename: Robert S
authors.initials: RS
authors.lastname: Marks
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008027:Light; D008298:Maleates / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013267:Stilbenes / Q000737:chemistry*; D014783:Viscosity; D014867:Water / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D008298:Maleates; D009930:Organic Chemicals; D012997:Solvents; D013267:Stilbenes; D014867:Water; C008311:maleamic acid