pH- and DNA-induced dual molecular light switches based on a novel ruthenium(II) complex.
A novel Ru(II) complex, [Ru(bpy)(2)(btppz)]Cl(2), where bpy=2,2'-bipyridine and btppz=benzo[h]tripyrido[3,2-a:2',3'-c:2'',3''-j]phenazine, has been synthesized and characterized. The pH effects on UV-visible (UV-vis) absorption and emission spectra of the complex have been studied and ground- and excited-state ionization constants of the complex have been derived. The calf thymus DNA (ct-DNA) binding properties of the complex were investigated with UV-vis absorption and luminescence spectrophotometric titrations, steady-state emission quenching by [Fe(CN)(6)](4-), DNA competitive binding with ethidium bromide, DNA melting experiments, reverse salt titrations and viscosity measurements. The complex was demonstrated to act as dual molecular switches: pH-induced "on-off" emission switch with an on-off intensity ratio of approximately 54 which is favorably compared with those reported for structurally analogous Ru(II) complexes, and a DNA molecular light switch with a luminescence enhancement factor of 22 as it intercalatively bound to the DNA.
Chen
Yan-Min
YM
College of Chemistry and Key Laboratory of Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing 100875, China.
Liu
Yan-Ju
YJ
Li
Qi
Q
Wang
Ke-Zhi
KZ
D000818:Animals; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D006575:Heterocyclic Compounds, 3-Ring / Q000138:chemical synthesis / Q000737:chemistry*; D006576:Heterocyclic Compounds, 4 or More Rings / Q000138:chemical synthesis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D012428:Ruthenium / Q000737:chemistry*; D014466:Ultraviolet Rays
D006575:Heterocyclic Compounds, 3-Ring; D006576:Heterocyclic Compounds, 4 or More Rings; D012428:Ruthenium; D004247:DNA; C427203:calf thymus DNA