The interaction of surfactant-cobalt(III) complexes [Co(bpy)(dien)TA](ClO4)3 · 3H2O (1) and [Co(dien)(phen)TA](ClO4)3 · 4H2O (2), where bpy = 2,2'-bipyridine, dien = diethylenetriamine, phen = 1,10-phenanthroline and TA = tetradecylamine with human serum albumin (HSA) under physiological conditions was analyzed using steady state, synchronous, 3D fluorescence, UV/visabsorption and circular dichroism spectroscopic techniques. The results show that these complexes cause the fluorescence quenching of HSA through a static mechanism. The binding constant (Kb ) and number of binding-sites (n) were obtained at different temperatures. The corresponding thermodynamic parameters (∆G°, ∆H° and ∆S°) and Ea were also obtained. According to Förster's non-radiation energy transfer theory, the binding distance (r) between the complexes and HSA were calculated. The results of synchronous and 3D fluorescence spectroscopy indicate that the binding process has changed considerably the polarity around the fluorophores, along with changes in the conformation of the protein. The antimicrobial and anticancer activities of the complexes were tested and the results show that the complexes have good activities against pathogenic microorganisms and cancer cells.

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The kinetics of electron transfer reaction (ETR) between the surfactant cobalt(III) complex ion, Cis-[Co(ip) 2 (C 12 H 25 NH 2 ) 2 ](ClO 4 ) 3 , Cis-[Co(dpq) 2 (C 12 H 25 NH 2 ) 2 ](ClO 4 ) 3 and Cis-[Co(dpqc) 2 (C 12 H 25 NH 2 ) 2 ](ClO 4 ) 3 (ip = imidazo [4,5-f][1,10]phenanthroline, dpq = dipyrido[3,2-d:2'-3'-f]quinoxaline, dpqc = dipyrido [3,2-a:2',4'-c](6,7,8,9-tetrahydro)phenazine, 5 C 12 H 25 NH 2 =dodecylamine) and Fe 2+ ion in micelles as well as β-cyclodextrin (β-CD) were studied at different temperatures by spectrophotometric method under pseudo first order conditions using an excess of the reductant. The results of surfactant complex containing aromatic ligands ETR higher than that of aliphatic ligands due to the results have been explained based on the hydrophobic effect. Experimentally the reactions were found to be second order and the electron transfer postulated as outer sphere. The rate constant increases with increase in the concentration of micelles but inclusion of the long aliphatic chain of the 10 surfactant cobalt(III) complexes into β-cyclodextrin decreases the rate of the reaction. Thermodynamic parameters were evaluated. 30 great deal of interest [9,10] because of their potential to prolong the lifetime of charge-transfer states, a goal of electron-transfer studies aiming to utilize solar energy [11]. Majumdar and Mahapatra [12] studied the electron transfer reactions between cobalt(III) and iron(II) complexes in cationic micellar medium (N-cetyl-N,N,N trimethyl ammonium bromide) and also in reverse micellar medium. The rate of the reaction was found to mainly depend on the inter-phase environment of the micelles and reverse micelles. Micelle-forming properties and electron transfer reactions of many surfactant metal complexes have been studied in our 35 laboratory [13-16]. Recently, we have reported on the outer-sphere electron transfer reactions between cis-[Co(en) 2 (C 12 H 25 NH 2 ) 2 ](ClO 4 ) 3, cis-[Co(trien)(C 12 H 25 NH 2 ) 2 ](ClO 4 ) 3 and iron(II) in the micelles formed by these complexes [Co(dpqc) 2 (C 12 H 25 NH 2 ) 2 ](ClO 4 ) 3 used as oxidants were prepared as reported by us earlier [34]. A stock solution of Fe(ClO 4 ) 2 was prepared by dissolving pure iron powder in slight excess of perchloric acid. The concentration of Fe 2+ ion was determined by a method similar to that reported in the literature [35] the ionic strength of the solution was adjusted by the addition of sodium 30 perchlorate solution. Kinetic measurementsThe rate of the reaction was measured spectrophotometrically using a Shimadzu -1800 UV-Visible spectrophotometer equipped with water Peltier system (PCB 150). The temperature was controlled within ± 0.01 0 C. A solution containing the desired concentration of β-cyclodextrin and surfactant cobalt(III) complexes in oxygen-free water was placed in a 1-cm cell, which was 35 then covered with a serum cap fitted with a syringe needle. This cell was placed in a thermostated compartment in the spectrophotometer and then the solution containing Fe 2+ was added a...