Tuning Reactivity of Platinum(II) Complexes

= (k2[B]o + k-2) ([A]t- [A]eq) (2.10)
Separation of variables and integration gives:
This results in
ln
[ ] d[
A]
( [ A]
− [ A]
)
t
( [ ] ) dt
A t
∫ [ A]
= − 2 B 0 + k−
[ A ] t - [ A ] e q
[ A ] 0 - [ A ] e q
k 2 ∫
0 0
(2.11)
t eq
= - ( k 2 [ B ] 0 + k -2 ) t
= -k o b s t
w h e r e , k o b s = k 2 [ B ] 0 + k -2
9
( 2 .1 2 )
Under pseudo first-order conditions, the experimental first order rate constant, kobs, is
given by:
-d [M L 3 X ]
d t
w ith
= k o bs [M ]
k o b s = k 2 [Y ] + k -2 (2 .1 3 )
A plot of kobs versus the initial concentration of the nucleophile, [B]0 = [Y]0, is linear with
a slope equal to the second-order rate constant, k2, and the y-intercept value equal to the
first-order rate constant, k-2. Typical kinetic plots are shown in Figure 2.3. A plot which
passes through zero implies that the forward reaction is irreversible and directly goes to
completion, whereas a non-zero y-intercept signifies a back reaction in which the
nucleophile Y is being substituted from the metal centre by the solvolysis process.