Tuning Reactivity of Platinum(II) Complexes

Figure 2.5: A schematic diagram of a continuous flow kinetic system. d = distance
from the mixer to the point of observation.
In the stopped-flow method the two reagents (A &B) are rapidly mixed under pressure
(800 kPa) into the reaction chamber (Mixing jet in Figure 2.6). The mixing takes about
10 -3 s, then the solution is driven into the cuvette where the solution mixture is allowed
to rest at a fixed time interval (rest period), when the stop syringe rests against its seat.
During the rest period, the reactive species is monitored and detected
spectrophotometrically. The reaction manifold is maintained at a pre-determined
constant temperature during the reaction stage and at the injection point. Once the
reactants impinge on each other in the observation chamber, the data acquisition
system promptly records the absorbance-time resolved kinetic trace at a set
wavelength. The kinetic traces are processed and the observed (pseudo) first-order rate
constants evaluated by an online computer program. 16,28 A typical single exponential
kinetic trace acquired on a stopped-flow reaction analyzer is shown in Figure 2.7.
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