Synthesis, micellar properties, DNA binding and antimicrobial studies of some surfactant–cobalt(III) complexes

A new class of surfactant–cobalt(III) complex ions of the type, cis-[Co(X) 2(C 14H 29NH 2)Cl] 2+ (where X = ethylenediamine (en), or 2,2'-bipyridyl (bpy), or 1,10-phenanthroline (phen)) and cis-[Co(trien)(C 14H 29NH 2)Cl] 2+ (trien = triethylenetetramine) were synthesized and characterized by IR, NMR, UV–visible electronic absorption spectra, elemental analysis and metal analysis. The critical micelle concentration (CMC) values of these surfactant–cobalt(III) complexes in aqueous solution were obtained from conductance measurements. Specific conductivity data (at 298, 308, 318 and 328 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (Δ G 0 m, Δ H 0 m and Δ S 0 m). Interactions between calf thymus DNA and the surfactant–cobalt(III) complexes in aqueous solution have been investigated by electronic absorption spectroscopy, emission spectroscopy and viscosity measurements. The electrostatic interactions, van der Waals interactions and/or partial intercalative binding have been observed in these systems. The surfactant–cobalt(III) complexes were screened for their antibacterial and antifungal activities against various microorganisms. The results were compared with the standard drugs, Ciprofloxacin and Fluconazole respectively.