Investigation of stable solid diazonium salt by molecular structure, Hirshfeld surface analysis, optical and electrochemical studies, and applications

The title compound is a new pyrazolone derivative which was synthesized starting from p-sulphophenyl-3-methyl-5-pyrazolone (1) by nitrosation at low temperature to afford the corresponding p-sulphophenyl-3-methyl-4-nitroso-5-pyrazolone can exist both in nitroso (2a) and oxime tautomeric forms (2b). Reduction of latter using zinc with hydrochloric acid furnished 4-amino-p-sulphophenyl-3-methyl-5-pyrazolone (3). diazotization (3) under careful control pH afforded diazonium salt (4) re-crystallized acidified ethanol crystal suitable for X-ray studies. UV–visible spectrum cyclic voltammetric studies were also carried out indicating λmax 420 nm HOMO-LUMMO energy gap calculated (Eg) 2.95 eV. molecular structures clarified single diffraction indicated that it crystallizes as sodium triclinic space group P -1, 4-azo-pyrazolone sulphophenyl groups being nearly coplanar. To get an insight intermolecular interactions crystal, Hirshfeld surface analysis out.