Synthesis, characterization and cancer cell growth inhibition activity of ruthenium(II) complexes bearing bidentate pyrrole-imine ligands

Abstract A series of bidentate pyrrole-imine ligands, [C 4 H 3 NH-(2-CH=N-R)] ( 1 , R = cyclohexenyl; 2, R = CH 2 CH 2 -1-cyclohexenyl; 3 , R =  t Bu; 4 , R = CH 2 -2-furyl; 5 , R = 2-methoxylphenyl; 6 , R = phenyl; 7 , R = 3-nitrophenyl; 8 , R = 2,6-di-isopropylphenyl; 9 , R = 2,4,6-trimethylphenyl), were synthesized and their corresponding ruthenium metal compounds {Ru ( ɳ 6 -p -cymene)[C 4 H 3 N-(2-CH=N-R)]Cl} ( Ru-1 ∼ Ru-9 ) were also synthesized. These ligands and ruthenium compounds were all characterized by 1 H and 13 C NMR spectroscopy and some of their structures are also determined by single crystal X-ray crystallography. The Ru-1 ∼ Ru-9 showed excellent GI 50 for PC-3 and DU-145 with the range of 3.83–12.13 and 4.25–11.22 μM, respectively. Among of these ruthenium compounds, Ru-6 has the best activity indicating phenyl ring is the key group on the imine substituents of these ruthenium compounds.