Malononitrile-Substituted Indole Compounds as Highly Effective Catalysts in the Catalytic Electrooxidation of Hydrazine

Abstract

Novel malononitrile-substituted indole compounds, namely, 2-((5-(2-(2,5-dimethylphenyl)-1-methyl-1H-indol-3-yl)thiophene-2-yl)methylene)malononitrile (10), 2-((5-(2-(2,5-dimethyl phenyl)-1-methyl-1H-indol-3-yl)furan-2-yl)methylene)malononitrile (11), and 2-(4-(2-(2,5-dimethylphenyl)-1-methyl-1H-indol-3-yl)benzylidene)malononitrile (12) were synthesized by using Suzuki-Miyaura coupling, Knoevenagel condensation, electrophilic cyclization, and Sonogashira coupling reactions. The yields were obtained in 94%, 93%, and 97%, respectively. Electrochemical measurements, including cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS), were performed to investigate the electrocatalytic behavior of compounds 10, 11, and 12. The specific activity of compound 12 for hydrazine electrooxidation was determined as 3.941 mA/cm2 with long-term stability.