In this study, we developed an anthracene-based fluorescence PET sensor (AMG) was developed for detecting high pH values and water content in organic solvents. A guanidine group as a proton receptor was covalently attached to an anthracene fluorophore to afford highly polar AMG, with reasonable solubility in highly basic solution. The fluorescence of AMG increased almost linearly with decreasing pH in the range 11.0–13.0. AMG also exhibited a fluorescence turn-on response to water in various organic solvents such as 1,4-dioxane, DMF, CH3CN, and EtOH. The peak intensity of the fluorescence was almost proportional to the amount of water. Two linear regression curves were used to quantitatively detect a broad range of water content in each solvent.
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and used without further purification. The solvents were dried using the standard method and stored over 4 Å molecular sieves prior to use.
Melting points were measured using an MEL-TEMP II melting point apparatus and are uncorrected. 1H and 13C NMR spectra were recorded at 300 and 75 MHz, respectively, using a Varian Unity Plus 300 spectrometer. The high-resolution mass spectral data (ESI) were obtained using a Waters SYNAPT G2 mass spectrometer. Absorption spectra were measured using a Varian Cary 300 UV–VIS spectrophotometer, and the fluorescence measurements were carried out using a Horiba dual-FL fluorescence spectrophotometer.
2.2 Synthesis of 3-(anthracen-9-ylmethyl)-1,1-dimethylguanidine …show more content…
The pH value of the sample solution was slightly changed by adding a small amount of HCl or NaOH. All the fluorescence measurements with pH changes were performed at an excitation at 367 nm in the presence of NaCl (0.1 M) to maintain a constant ionic strength.
Prior to each water content measurement, the sample solutions with an AMG concentration of 2.0 × 10-5 M containing different water contents in organic solvents were prepared. Fluorescence was measured at an excitation wavelength at 370 nm in 1,4-dioxane and 368 nm in DMF, CH3CN, and EtOH. The fluorescence peak intensities were observed at 414 nm for 1,4-dioxane, 415 nm for DMF, and 411 nm for CH3CN and
and used without further purification. The solvents were dried using the standard method and stored over 4 Å molecular sieves prior to use.
Melting points were measured using an MEL-TEMP II melting point apparatus and are uncorrected. 1H and 13C NMR spectra were recorded at 300 and 75 MHz, respectively, using a Varian Unity Plus 300 spectrometer. The high-resolution mass spectral data (ESI) were obtained using a Waters SYNAPT G2 mass spectrometer. Absorption spectra were measured using a Varian Cary 300 UV–VIS spectrophotometer, and the fluorescence measurements were carried out using a Horiba dual-FL fluorescence spectrophotometer.
2.2 Synthesis of 3-(anthracen-9-ylmethyl)-1,1-dimethylguanidine …show more content…
The pH value of the sample solution was slightly changed by adding a small amount of HCl or NaOH. All the fluorescence measurements with pH changes were performed at an excitation at 367 nm in the presence of NaCl (0.1 M) to maintain a constant ionic strength.
Prior to each water content measurement, the sample solutions with an AMG concentration of 2.0 × 10-5 M containing different water contents in organic solvents were prepared. Fluorescence was measured at an excitation wavelength at 370 nm in 1,4-dioxane and 368 nm in DMF, CH3CN, and EtOH. The fluorescence peak intensities were observed at 414 nm for 1,4-dioxane, 415 nm for DMF, and 411 nm for CH3CN and