Karuppiah Nagaraj*, Raja Kaliyaperumal, Subramaniam Kamalesu, Chandramohan Govindasamy, Allur Subramaniyan Sivakumar, Suriyan Radha, Manda Saritha and Chelladurai Karuppiah Kinetics and outer sphere electron transfer of some metallosurfactants by Fe(CN) 6 4- in microheterogenous medium: a detailed thermodynamic approach https://doi.org/10.1515/zpch-2023-0338 Received September 2, 2023; accepted November 5, 2023; published online November 28, 2023 Abstract: We report the rate of electron transfer reaction of complexes, cis- [M(ED) 2 (DOD) 2 ] 3+ (1), cis-[M(DP) 2 (DOD) 2 ] 3+ (2), cis-[M(TRE)(DOD) 2 ] 3+ (3), cis-[M(bpy) 2 (DOD) 2 ] 3+ (4) and cis-[M(PA) 2 (DOD) 2 ] 3+ (5) (M:Co, ED: ethylenediamine, TRE: triethyle- netetramine, DP: diaminopropane, PA: phenanthroline, C 12 H 25 NH 2 : dodecylamine (DOD) and bpy: bipyridine) and hexacyanoferrate ion in surface active ionic liquids (BMIM)Br were studied at 298–323 K by electronic absorption spectroscopy. Surfactant complexes 4 and 5, which have a higher ETR than complexes 1–3 based on the results obtained, have been explained based on the states of aggregation and hydrophobic transformations between the hydrocarbon portion of the surfactant compounds and (BMIM)Br. As a result, surface-active agent micelles in (BMIM)Br and increase ETR in between the system. The investigation of kinetic statistics outcomes suggest that reduction reaction *Corresponding author: Karuppiah Nagaraj, School of Pharmacy, National Forensic Sciences University, 6M56+XP8, Police Bhavan Rd, Sector 9, Gandhinagar, Gujarat 382007, India, E-mail: surfactantnagaraj@gmail.com Raja Kaliyaperumal, Department of Chemistry, St. Joseph University, Chumoukedima, Nagaland 797115, India Subramaniam Kamalesu, Department of Chemistry, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Tiruchirappalli 621105, Tamil Nadu, India Chandramohan Govindasamy, Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 11433, Saudi Arabia Allur Subramaniyan Sivakumar, Department of Orthopaedic Surgery, Dongtan Sacred Heart Hospital, Hallym University, College of Medicine, Hwaseong, Republic of Korea Suriyan Radha, Department of Chemistry, Saiva Bhanu Kshatriya College, Aruppukkottai, Tamil Nadu, India Manda Saritha, Humanities and Sciences, St. Peters Engineering College, St Peters College Rd, Opposite TS Forest Academy Dullapally, Maisammaguda, Medchal, Hyderabad, Telangana 500043, India Chelladurai Karuppiah, Battery Research Center for Green Energy, Ming Chi University of Technology, New Taipei City 24301, Taiwan Z. Phys. Chem. 2023; aop