M. Treguer et al., Redox kinetics of Chini-type platinum carbonyl clusters studied by time-resolved pulse radiolysis, J PHYS CH A, 105(25), 2001, pp. 6102-6108
The reduction mechanism of Chini clusters [Pt-3(CO)(6)]n(2-) (n = 6-9) has
been studied by nanosecond pulse radiolysis in water/2-propanol solution. T
he monoelectronic reduction of all [Pt-3(CO)(6)](6)(2-) by the alcohol radi
cals produced by the solvent radiolysis is supposed to yield short-lived [P
t-3(CO)(6)](6)(3-) clusters that split immediately into [Pt-3(CO)(6)](4)(2-
) and [Pt-3(CO)(6)](2-) [Pt-3(CO)(6)](2)(-) dimerizes to the stable tetrame
r [Pt-3(CO)(6)](4)(2-) with a diffusion-controlled rate constant. When only
a fraction of the [Pt-3(CO)(6)](6)(2-) in solution is reduced, a slower ad
dition reaction between excess [Pt-3(CO)(6)](6)(2-) and the newly formed [P
t-3(CO)(6)](4)(2-) gives then two [Pt-3(CO)(6)](6)(2-). Results concerning
the early steps of the reduction of clusters of higher nuclrarity [Pt-3(CO)
(6)](n)(2-) (n = 7-9) are also presented. The general reduction mechanism o
f the platinum carbonyl compounds [Pt-3(CO)(6)](n)(2-) displays some simila
rities with the reduction of n = 6; i.e., stable [Pt-3(CO)(6)](4)(2-) are f
ormed together with the transient [Pt-3(CO)(6)](n-4)(-).