Tuning Reactivity of Platinum(II) Complexes

List of Figures
Figure 2.1: Structures of some monofunctional platinum(II) complexes active against human
colon carcinoma cell line (HCT-116). 11 ................................................................................. 2
Figure 2.2: Potential energy profiles of different mechanisms occurring at a square planar Pt(II) centre as
proposed by Langford-Gray. 5 .............................................................................................. 4
Figure 2.3: Typical plots of the pseudo first-order rate constants, kobs versus. the concentration of
the entering nucleophiles for the substitution reaction of a dinuclear Pt(II) complex at 298 K in
aqueous solution. .............................................................................................................. 10
Figure 2.4: Summary of reaction techniques and their associated time scales available for the monitoring
chemical kinetics. 28 ........................................................................................................... 17
Figure 2.5: A schematic diagram of a continuous flow kinetic system. d = distance from the mixer
to the point of observation. ................................................................................................ 19
Figure 2.6: Schematic diagram of a stopped flow apparatus. 13 ............................................... 20
Figure 2.7: Kinetic trace at 448 nm for the substitution reaction between CH3PhisoqPtCl (0.054
mM) and I - (6.06 mM) at 298 K, I = 0.1 M Li(SO3CF3) in methanol. .......................................... 20
Figure 2.8: A schematic diagram of a UV-Visible Spectrophotometry set-up. .......................................... 21
Figure 2.9: Rates of Pt(II) complexes correlated with trans-[Pt(py)2Cl2] as reference, for different
entering nucleophiles: • = trans-[Pt(PEt3)2Cl2] in methanol at 30 °C; ▲ = [Pt(en)Cl2] in water at
35 °C. 18............................................................................................................................. 27
Figure 2.10: The steric effect on the trigonal bipyramidal intermediate of the cis isomer in
comparison to trans-isomer. 36 ............................................................................................ 32
Figure 2.11: Geometry of an aryl square-planar complex showing the ortho- substituents block
the site of attack. 6,26,37 ........................................................................................................ 32
Figure 2.12: (a) σ-donation from the filled ligand px orbital to vacant metal 5dx 2 -y 2 orbital. (b) πback-donation
from the filled metal dxz orbital to the antibonding linear combination of carbons’
px orbitals in C2H4. 51 .......................................................................................................... 37
ii