Tuning Reactivity of Platinum(II) Complexes

List of Figures
Figure 6.1: Spectrophotometric titration curve of Pt3 with NaOH in the pH range 2-9, I =
1.0 M (NaClO4), T = 25 °C. Inset: plot of Absorbance vs pH at 280 nm. ..................................... 10
Figure 6.2: DFT optimised structures of the dinuclear platinum(II) complexes. ............... 14
Figure 6.3: The 1 H NMR spectra of the reaction of Pt1 with thiourea (2.0 mM) in DMF-
d7, at 30 °C showing the release of the dps bridging ligand. ........................................................... 16
Figure 6.4: (a) Stopped-flow and (b) UV-Vis spectrophotometric curves for Pt2 with TU
at 305 nm, T = 298 K, I = 0.10 M (0.01 M HClO4, adjusted with NaClO4), pH = 2.0. ............. 18
Figure 6.5: Concentration dependence of kobs(1 st ) for the displacement of aqua ligands in
Pt1 by thiourea nucleophiles and ionic nucleophiles, pH = 2.0, T = 298.15 K, I = 0.10 M
(0.01 M HClO4, adjusted with NaClO4). ..................................................................................................... 19
Figure 6.6: Concentration dependence of kobs(2 nd ) for the displacement of bridging ligand
in Pt1 by thiourea nucleophiles and ionic nucleophiles, pH = 2.0, T = 298.15 K, I = 0.10 M
(0.01 M HClO4, adjusted with NaClO4). ..................................................................................................... 20
Figure 6.7: Plots of ln(k2(1 st )/T) versus (1/T) for the first step reaction of Pt1 with a
series of different nucleophiles at varying temperatures. .............................................................. 23
Figure 6.8: Plots of ln(k2(2 nd )/T) versus (1/T) for the second step reaction of Pt1 with a
series of different nucleophiles at varying temperatures. .............................................................. 24
Figure 6.9: Schematic structures of Pt1 and free ligand illustrating the twisted
conformation of Pt1 and steric factor ....................................................................................................... 27
List of Tables
Table 6.1: Summary of the pKa values obtained for the deprotonation of platinum-
bound water of the different complexes. ................................................................................................. 11
Table 6.2: DFT-calculated parameters for platinum(II) complexes .......................................... 13
Table 6.3: Summary of rate constants and activation parameters with the
corresponding standard deviations for the substitution of aqua ligands by neutral (TU,
DMTU, and TMTU) and ionic (I - , Br - and SCN - ) nucleophiles, I = 0.10 M (NaClO4). ............. 21
Table 6.4: Summary of rate constants and activation parameters with the
corresponding standard deviations for the replacement of bridging ligand by neutral
(TU, DMTU, and TMTU) and ionic (I
ii
- , Br- and SCN- ) nucleophiles, I = 0.10 M (NaClO4). ... 22