Development of Push-π-Pull phenothiazine-vinyl-isophorone fluorophore: Novel Solvatochromic and pH Indicator.

Knoevenagel condensation of phenothiazine-3, 7-dicarbaldehyde with isophorone yielded a new phenothiazine derivative (PTZ-c) fluorophore. The solvatochromic and pH-sensing abilities of PTZ-c, an asymmetric fluorophore with a single isophorone molecule, were shown to be exceptional. PTZ-c showed very delicate absorbance and emission spectra. When the polarity of the solvent was increased, the PTZ-c emission spectra showed greater sensitivity than the absorption spectra. Multiple spectroscopic techniques, including Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance ( 1 H NMR), and mass spectrometry, were used to characterize the manufactured PTZ-c sensor. To demonstrate the beneficial solvatochromic behavior associated with ICT, the absorption spectra of the synthesized DA PTZ-c dye were analyzed in a number of solvents of varying polarity. Band intensity and wavelength of PTZ-c emission were also found to be highly solvent dependent. It was observed that when solvent polarity was raised to a maximum of 4122 cm -1 , the Stoke' shift also rose. In order to analyze the Stoke's shift that depends on the solvent, a linear connection between solvation and energy was used. Investigation of PTZ-c's quantum yield (ф) was also conducted. Both the absorbance and fluorescence spectra in DMF as a function of pH were studied. The fluorescence peak was seen at 562 nm, whereas the greatest absorption wavelengths were at 403 and 317 nm. It was shown that the pH-sensing mechanism depends on the proton abstracted from the PTZ-c chromophore, which causes a color shift and a variation in both emission and colorimetric properties.