Synthesis, Characterization, Fluorescence and Interactions with DNA/BSA Properties of Ruthenium Ferulate Complexes

We synthesized two novel mononuclear ruthenium complexes, [Ru(cym)(L)Cl]Cl (Ru-1) and [Ru(bpy)(2)(L)] Cl-2 (Ru-2)(cym=cymene, bpy=2,2'-bipyridine, L=(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((4'-methyl-(2,2'-bipyridin)4-yl)methyl)acrylamide), with the modified natural product trans-ferulic acid. Their structures were determined by H-1 NMR, C-13 NMR and ESI-MS techniques. Optical properties and lipophilicity of complexes were characterized by using the fluorescence and UV-visible spectra. The results suggested that both complexes exhibited high water solubility. Ru-2 showed good fluorescence performance with the maximum emission wavelength at 631 nm in the near infrared area and had pH responsive ability (pH=8 similar to 10). Additionally, Ru-2 exhibited high singlet oxygen quantum yield (Phi=0.70), which might be expected to become an efficient photosensitizer. Both of the complexes binded to CT-DNA through intercalation mode (K-b: 1.210 x 10(4) L.mol(-1) for Ru-1; 1.233 x 10(3) L.mol(-1) for Ru-2) and interacted with BSA with one site, causing static quenching of their fluorescence (K-a: 1.94 x 10(4) for Ru-1; 2.45 x 10(4) for Ru-2).