Mg. Peterleitner et al., ELECTRON-TRANSFER-INDUCED CLEAVAGE AND FORMATION OF C-H-BONDS IN 17(E)OVER-BAR AND 19(E)OVER-BAR PLATINUM COMPLEXES, Russian chemical bulletin, 44(6), 1995, pp. 1114-1118
The electrochemical behavior of platinum complexes [Pt(eta(4)-diene)(e
ta(5)-C(5)R(5))](BF4-)-B-+ (1(+), diene = C(5)Me(5)H, R = H; 2(+), die
ne = C(5)Me(5)H, R = Me; 3(+), diene = C6H8, R = Me; 4(+), diene = C8H
12, R = Me) was studied by cyclic voltammetry. Complexes 1(+) and 2(+)
are shown to be capable of both oxidation and reduction. One-electron
reduction of 2f gives a mixture of two neutral isomeric complexes 5a,
b of eta(3)-allylic and sigma,pi-olefinic type due to the cleavage of
C-H bonds in the methyl groups of the pentamethylcyclopentadiene ligan
d of 19 $$($) over bar e complexes 2. The preparative electrochemical
oxidation of 2(+) results in cleavage of the C-H bond at the sp(3)-hy
bridized pentamethylcyclopentadiene carbon atom in 17 $$($) over bar e
dication radical 2(2+) to give the decamethylplatinocene dication [Pt
(eta(5)-C(5)Me(5))(2)](2+)(BF4)(2) (7(2+)). It is shown that one-elect
ron reduction of 7(2+) and one-electron oxidation of 5a,b is accompani
ed by the formation of C-H bonds to form 2(+).