Synthesis, micellization behaviour, DNA/RNA binding and biological studies of a surfactant cobalt(III) complex with dipyrido[3,2-a:2',4'-c](6,7,8,9-tetrahydro)phenazine.

A new surfactant cobalt(III) complex, cis-Co(dpqc)2(DA)23, where dpqc = dipyrido3,2-a:2',4'-cphenazine and DA = dodecylamine, has been synthesized and characterized by elemental analysis, UV-Visible, IR and NMR spectra. The critical micelle concentration (CMC) value of this surfactant cobalt(III) complex in aqueous solution was obtained from conductance measurements. The conductivity data (at 303, 308, 313, 318 and 323 K) were used for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG(0) m, ΔH(0) m and ΔS(0) m). Absorption, fluorescence, cyclic voltammetry, circular dichroism and viscosity experiments have been carried out to study the interaction of the surfactant cobalt(III) complex with DNA and RNA. The results suggest that the complex can bind to nucleic acids by intercalation via both the dpqc ligand and the long aliphatic chain of the complex into the base pairs of DNA/RNA. In vitro cytotoxicity experiments show that the surfactant cobalt(III) complex exhibits cytotoxic activity against the HepG2 (human hepatocellular liver carcinoma) tumor cell lines and found to be active.