求高手翻译Figure 1 shows the normalized absorption spectra of

Figure 1 shows the normalized absorption spectra of [Ru(bpy)3-n(dpb)n]2þ (n=1-3) and [Ru(bpy)3]2þ. Comparison of these spectra can lead to the assignments of a πfπ* transition to the bpy ligand centered at 286 nm， a πfπ* ... Figure 1 shows the normalized absorption spectra of [Ru(bpy)3-n(dpb)n]2þ (n=1-3) and [Ru(bpy)3]2þ. Comparison of these spectra can lead to the assignments of a πfπ* transition to the bpy ligand centered at 286 nm， a πfπ* transition to the dpb ligand centered at both 315 and 400 nm， and a 1MLCT transition over the visible region， in good agreement with the previous results.8 The dpb ligand renders the 1MLCT of [Ru(bpy)3-n(dpb)n]2þ 100 nm red-shifted compared to that of [Ru(bpy)3]2þ. In aqueous solutions， [Ru(bpy)3-n(dpb)n]2þ undergoes a further bathochromic shift (Supporting Information)， favorable for PDT application. The 3MLCT emissions of [Ru(bpy)3-n(dpb)n]2þ fall in the region of NIR (Table 1 and Supporting Information)， recorded on a Confocal Laser Micro-Raman Spectroscope (532 nm excitation). On the same instrument， an emission centered at 619nmwas observed for [Ru(bpy)3]2þ， in linewith the result obtained on a conventional fluorescence spectrophotometer. The electrochemical properties of these complexes were examined using cyclic voltammetry (Table 1 and Supporting Information). [Ru(bpy)2(dpb)]2þ displays a reversible Ru- (III/II) based oxidation wave at þ1.43 V versus SCE. The 0.14 V of anodic shift compared to that of [Ru(bpy)3]2þ (þ1.29 V) may be attributed to the more electronegative character or stronger π-accepting feature of dpb than bpy. This is supported by the less negative reduction potential of -0.60 V for dpb compared to -1.33 V for bpy (Table 1). For [Ru(bpy)(dpb)2]2þ and [Ru(dpb)3]2þ， the dpb ligand-based first reduction potentials appear at -0.50 V and -0.47 V， respectively， in accordance with the previous results.8 The oxidation processes of [Ru(bpy)(dpb)2]2þ and [Ru(dpb)3]2þ are no longer reversible with the peak potentials at 1.65 and 1.64 V， respectively. Carlson and RorerMurphy ascribed the irreversible oxidation wave of [Ru(dpb)3]2þ to the oxidation of the dpb ligand.8 The DNA titration approach was used to examine the binding abilities of these complexes toward calf thymusDNA (CT-DNA). The absorption spectrum of [Ru(bpy)2(dpb)]2þ shows negligible changes upon the addition of DNA， indicative of a weak interaction. For [Ru(bpy)(dpb)2]2þ and [Ru(dpb)3]2þ， the MLCT absorbance increased at first and then decreased continuously with the addition of CT-DNA. Such behavior was also observed for other Ru(II) complexes， probably due to the DNA-induced complex aggregation. 3g，5，13 Thus， an EB displacement assay was carried out to compare the DNA binding affinities of these complexes (Table 1 and Supporting Information). The binding constants of [Ru(bpy)(dpb)2]2þ and [Ru(dpb)3]2þ are much higher than that of [Ru(bpy)2(dpb)]2þ， presumably due to themore hydrophobic property of dpb than bpy (Supporting Information)