Water-tunable solvatochromic and nanoaggregate fluorescence: dual colour visualisation and quantification of trace water in tetrahydrofuran

Abstract

While investigating the unique optical properties of aminobenzopyranoxanthenes (ABPXs), organic fluorescent dyes with the fusion of two rhodamines, we have found that the spirolactone form of ABPXs exhibited solvatochromic fluorescence in organic solvents. Detailed spectrophotometric and theoretical analyses showed that the solvatochromic fluorescence of ABPXs originated from the photo-excited charge separation in solvents of different dipolarities. Further studies revealed that fluorescent nanoaggregates were also formed in highly concentrated solution. The intriguing dual fluorescence properties of ABPXs were tunable in response to the water content, and served as a new detection principle for naked-eye visualisation (above 0.5 wt%) and quantification (0.010-0.125 wt%) of water in tetrahydrofuran.

Chemical Sensors for Water Detection in Organic Solvents and their Applications

“…Tanioka, M et al [37] . developed an organic trans amino‐benzopyran xanthenes ( 12 a‐ ‐ b ), which exhibits nanoaggregate and fluoro‐solvatochromic properties.…”

“…Tanioka, M et al [37] developed an organic trans aminobenzopyran xanthenes (12 a--b), which exhibits nanoaggregate and fluoro-solvatochromic properties. The fluorescence of 12 a showed a red-shift of 145 nm with increasing solvent polarity and blue fluorescence was observed at 430 nm in nonpolar solvents.…”

Development of an intramolecular charge transfer-type colorimetric and fluorescence sensor for water by fusion with a juloidine structure and complexation with boron trifluoride

“…Several strategies have been demonstrated to meet the requirement, such as intramolecular charge transfer (ICT), [5][6][7][8][9] excited state intramolecular proton transfer (ESIPT), [9][10][11] photo-induced electron transfer (PET), [12][13][14][15][16][17][18] aggregation-induced emission (AIE), 7,29,30 decoloration of hydrogen-bonding photochromic dyes, 31 and other water-triggered mechanisms. [19][20][21][22][23][24][25][26][27][28] Generally, in each system, there is a specic range of water concentration available for detection; AIE is observed in high water concentrations, 7,29,30 whereas other systems exhibit optical changes in a relatively low concentration range. In this context, a reasonable approach to incorporating two mechanisms into one sensor molecule has been developed to detect and determine water in organic solvent sensitively in a wide concentration range, including the combinations of ICT or PET and AIE, [32][33][34][35][36][37][38][39] two water-induced reactions, 40 and two ICT-related mechanisms, 41,…”

Gaining insight into the photophysical properties of a coumarin STP ester with potential for bioconjugation

“…37,38 This has been attributed to the fact that the models used (LM, B and KCV) do not consider molecular aspects of solvation and chemical interactions and should indicate the existence of a specific solvent effect, most probably intermolecular H-bonding between the solute and the solvent molecules. 34,36,37,39 When specific interactions between solute and solvent molecules can contribute to the Stokes shifts, models such as Ravi's model, which applies the empirical solvent polarity index, E T N (considering dipolarity/polarizability and acidity), are used to investigate the solvent-solute interaction effects on the Stokes shift. Good linear correlations were found for two separated solvent classes, polar protic (excluding PBS 22 mM) and aprotic, (i) indicating that this model allows accurate modeling of the Stokes shift variation of C392STP in both protic and aprotic solvents (Table 5); and (ii) suggesting the presence of an additional interaction between C392STP and polar protic solvents which is ignored in the reaction field approaches.…”