The association of like-charged ions in tunable protic pyrazolium salts

The association of like-charged ions is an elusive concept due to the lack of supporting experimental evidence. In the present work, 3,5-dimethyl-1-(p-substitutedphenyl)pyrazolium hexafluorophosphate (p-Cl (2a), p-Br (2b), p-OCH3 (2c)) tunable protic pyrazolium salts have been synthesized and characterized. The association of like-charged ions in the synthesized salts was observed, as evidenced by X-ray structure analysis of single crystals. The effect of the p-substituent on the association of like-charged ions has been investigated. DFT-D3 studies were performed to unravel the links between the experimentally obtained X-ray results for the solid phase and theoretically calculated results for an isolated system in the gas phase. Additionally, infrared analysis and molecular electrostatic potential analysis were conducted using DFT-D3 to get further information