Synthesis, crystal structure and DNA-binding studies of a Ru(II) complex containing two main ligands

A new Ru(II)-polypyridyl complex, [Ru(L)(dppz)2](PF6)4 (L = 5,5′-di(1-(trimethylammonio)methyl)-2,2′-dipyridyl cation; dppz = dipyrido[3,2-a:2′,3′-c]phenazine]), has been synthesized and structurally characterized. The binding of this complex with calf thymus DNA (CT-DNA) has been investigated by spectroscopic and viscosity measurement. Results indicate that the complex binds to CT-DNA via an intercalative mode. Moreover, the complex reveals a highly efficient DNA cleavage activity upon irradiation at 365 nm, during which supercoiled pBR322 DNA was converted to nicked DNA.