Ethynylated triphenylamine monoboronic acid chemosensors: Experimental and theoretical studies
New ethynylated triphenylamine boronic acid sensors 1 and 2 were designed and the photophysical properties, as well as the binding with tartaric acid and mandelic acid were studied. We found the emission intensity of the sensors is sensitive to the polarity of the solvents and the emission of sensor 2 is sensitive to protic solvents. Theoretical calculations on the low-lying excited states of these sensors predicted d-PET effect. Experimental observations show either a-PET effect or no significant PET effect for the sensors. The sensitivity of the emission of the sensors toward solvent polarity is used to rationalize the observed emission intensity-pH profiles.