Tuning Reactivity of Platinum(II) Complexes

Figure 7.5: 195Pt NMR spectra of mixtures HexPt-Cl and TU (1:2; 1:4 and 1:6 equiv.) in D2O, at 30
°C. Where A is the peak due to starting complex cis–[{PtCl(NH3)2}2–µ–NH2(CH2)6NH2] 2+, B and C
are intermediates, cis–[{PtCl(NH3)2}–μ–NH2–(CH2)6–NH2–{PtTU(NH3)2}] 3+ and cis–
[{Pt(TU)(NH3)2}2–μ–NH2(CH2)6NH2] 4+, respectively, while D is the final product cis–
[{Pt(TU)2NH3}2–μ–NH2(CH2)6NH2] 4+. ................................................................................................. 19
Figure 6: Typical kinetic traces for two step reaction between OctPt (0.1 mM) and TU (3 mM)
recorded at 363 nm, T =298K , pH = 2.0, I =0.1 M (NaClO4/HClO4). (a) A typical kinetic trace from
the stopped-flow for the simultaneous substitution of the aqua ligand (b) A typical kinetic trace (
in duplicate) for the release of ammine acquired by UV-Vis spectroscopy. ................................... 21
Figure 7.7: Concentration dependence of kobs(1 st ), s-1, for the simultaneous displacement of the
coordinated water molecules in OctPt by thiourea nucleophiles, pH =2.0, T =298 K, I =
0.1 M (NaClO4, adjusted with 0.01 M HClO4). .................................................................................... 21
Figure 7.8: Concentration dependence of kobs(2 nd ), s-1, for the displacement of the ammine ligand
in OctPt by thiourea nucleophiles, pH =2.0, T =298 K, I = 0.1 M (NaClO4, adjusted with 0.01 M
HClO4). .................................................................................................................................................. 22
Figure 7.9: Eyring plots forthe determination of the activation enthalpies and entropies for k2,1st
of all nucleophiles studied with OctPt complex. ................................................................................ 24
Figure 7.10: Eyring plots forthe determination of the activation enthalpies and entropies for
k2,2 nd of all nucleophiles studied with OctPt complex . ...................................................................... 25
List of Tables
Table 7.1:: Summary of selected DFT-calculated NBO charges, HOMO-LUMO energy gaps, Bond
lengths and angles of the studied Pt(II) complexes. ......................................................................... 11
Table 7.2 Summary of pKa values for the deprotonattion steps of aqua platinum(II) complexes at
25 °C. ..................................................................................................................................................... 14
Table 7.3 Summary of second order rate constants and activation parameters for flexible α, ωalkanediamine-bridged
platinum(II) complexes. ............................................................................. 23
ii