Effect of the proton-rich environment on pyrazolequinoline chemosensor by UV spectroscopy and quantum-chemical calculations

Semi-empirical calculations and optimization of molecular structure of the pyrazolequinoline in vacuum, in water and in a proton-rich environment were performed using Gaussian 09 software package. These studies have shown high probability of intermolecular hydrogen bonds that were formed by the protons with nitrogen atoms being potentially able to interact. The formation of pyrazolequinoline-acid complexes confirm the possibility of proton transfer process. These studies shown that the proton transfer mechanism is strongly dependent on environment properties like solvent parameters: Donor Number and Acceptor Number. The selective interaction of the proton with the molecule seems to be strong.