Interaction of hydroxy substituted dibenzoylmethanatoboron difluoride with hydrated ammonia in solution: A combined spectroscopic and computational study

UV-Vis absorption spectroscopy and quantum chemistry are employed to study the spectral features of a new organoboron dye ortho-hydroxy dibenzoylmethanatoboron difluoride (OHDBMBF₂). The compound shows promise for the detection of hydrated ammonia thanks to the ability to interact with proton acceptors. Specifically, a color change from colorless to red and a new long-wavelength absorption band at 500 nm have been noted after consecutive injections of ammonia and water into the solution of the dye. According to the DFT and TDDFT calculations, the response of OHDBMBF₂ to hydrated ammonia is caused by the deprotonation reaction. Based on the results of the theoretical simulations, the nature of the absorption bands of the neutral and anionic forms of the dye has been explained.