# Ru(II)-Dppz Derivatives and Their Interactions with DNA: Thirty Years and Counting
## 3 DNA Binding
### Effects of Tuning the Photophysical and Redox Properties
Modifications made to these ligands can result in important electronic effects that lead to changes in the photophysical and redox properties of these types of systems; see Table 1.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Complex**} & \multicolumn{4}{c}{**MeCN**} & \multicolumn{4}{c}{**H\({}_{2}\)O**} \\ \cline{2-10}  & \(\lambda_{\text{abs}}/\text{nm}\) & \(\lambda_{\text{nm}}/\text{nm}\) & \(\Phi\)/\% & \(\tau_{\text{ali}}/\text{ns}\) & \(\lambda_{\text{abs}}/\text{nm}\) & \(\lambda_{\text{emi}}/\text{nm}\) & \(\Phi\)/\% & \(\tau_{\text{ali}}/\text{ns}\) & Ref \\  & **(\(\mathbf{c/10^{4}}\) M\({}^{-1}\) cm\({}^{-1}\))** & \(\lambda_{\text{emi}}/\text{nm}\) & \(\Phi\)/\% & \((\mathbf{r_{\text{Ai}}/\text{ns}})\) & \((\mathbf{c/10^{4}}\) M\({}^{-1}\) cm\({}^{-1})\) & \(\lambda_{\text{emi}}/\text{nm}\) & \(\Phi\)/\% & \(\tau_{\text{ali}}/\text{ns}\) & (\(\mathbf{r_{\text{Ai}}/\text{ns}}\)) & \\ \hline \multirow{2}{*}{[Ru(\text{ppy})\({}_{2}\)(dppz)]\({}^{2+}\)} & - & 615 & - & - & \multicolumn{4}{c}{263 (11.7)} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{[70,71]} \\  & 325 (5.05) & & & & & \multicolumn{4}{c}{372 (2.18)} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{[91]} \\ \multirow{2}{*}{[Os(\text{pypydpz})]\({}^{2+}\)} & 375 (2.21) & 800 & 0.8 & 50 & - & - & - & - & \\  & 475 (1.46) & & & & & & & & \\ \hline \multirow{2}{*}{[Ru(\text{acac})\({}_{2}\)(dppz)]} & 554 (9100) & & & \multicolumn{4}{c}{Not soluble} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{[113]} \\  & 262 & 446 & - & - & - & \multicolumn{4}{c}{421} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{[113]} \\  & 264 & 276 sh & & & \multicolumn{4}{c}{264, 278 sh} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{[113]} \\  & 316, 352 & 630 & 2.1 & 180 (643) & 318 sh, 358 sh & - & - & - & \\  & 360, 368, 440 & & & & \multicolumn{4}{c}{372, 440 (2.34)} & \multirow{3}{*}{-} & \multirow{3}{*}{-} & \multirow{3}{*}{-} & \multirow{3}{*}{[113]} \\ \multirow{2}{*}{[Ru(\text{phen})\({}_{2}\)(dppz)]\({}^{2+}\)} & 264, 278 sh & & & \multicolumn{4}{c}{264, 276 sh} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{[113]} \\  & 316, 352 & 630 & 2.1 & 180 (643) & 312 sh, 358 sh & - & - & - & \\  & 360, 368, 440 & & & & \multicolumn{4}{c}{372, 440 (2.34)} & \multirow{3}{*}{-} & \multirow{3}{*}{-} & \multirow{3}{*}{-} & \multirow{3}{*}{[113]} \\ \multirow{2}{*}{[Ru(\text{phen})\({}_{2}\)(PHEAT)]\({}^{2+}\)} & 264, 278 sh & & & \multicolumn{4}{c}{264, 276 sh} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{[113, 114]} \\  & 312 sh, 354 sh & 662 & 1.1 & 191 (262) & 312 sh, 356 & - & - & - & \\  & 370, 438 & & & \multicolumn{4}{c}{374, 440 (2.27)} & \multirow{3}{*}{-} & \multirow{3}{*}{-} & \multirow{3}{*}{-} & \multirow{3}{*}{[114]} \\ \multirow{2}{*}{[Ru(\text{phen})\({}_{2}\)(HAT)]\({}^{2+}\)} & 262 & & \multicolumn{4}{c}{262} & \multirow{4}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{[115]} \\  & 4200 & 480 sh & & & \multicolumn{4}{c}{494 sh} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{[115]} \\ \multirow{2}{*}{[Ru(\text{pypy})\({}_{2}\)(HAT)]\({}^{2+}\)} & 282 & & \multicolumn{4}{c}{277 (5.90)} & \multirow{2}{*}{-} & \multirow{2}{*}{6\(\times\)} & \multirow{2}{*}{-} & \multirow{2}{*}{[115]} \\  & 420 & 420 & 703 & 1.6 a & & \multicolumn{4}{c}{432 (1.0)} & \multirow{2}{*}{742} & \multirow{2}{*}{6\(\times\)} & \multirow{2}{*}{-} & \multirow{2}{*}{[115]} \\  & 480 sh & & & & \multicolumn{4}{c}{484 sh} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{484 sh} & \multirow{2}{*}{[115]} \\ \multirow{2}{*}{[Ru(\text{HAT})\({}_{3}\)]\({}^{2+}\)} & 275 & & \multicolumn{4}{c}{275} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{[89]} \\  & 410 sh & 587 & 0.9 a & & \multicolumn{4}{c}{-} (89) & 410 sh & 596 & 0.013 & - \\  & 436 & & & \multicolumn{4}{c}{440 (2.10)} & \multirow{2}{*}{5 An example of that is the use of primary amines or acetylactonates that leads to complete non-emissive species, as in the case of [Ru(NH\({}_{3}\))\({}_{4}\)(dppz)]\({}^{2+}\) and [Ru(acac)\({}_{2}\)(dppz)] [118,119], while the use of polypyridine ligands with ligand-centered (LC) states (which are much more stabilized species than phenanthroline or pipyridine and which become acceptors of the MLCT transition) leads to luminescence in both the presence and absence of DNA [120].