The disappearance of tris(2,4-pentanedione)Iron(Hl), (FAA), tris(l,l,l-trifluoro-2,4-pentanedione)Iron(III), (TFFAA), and tris(1,1,1,5,5,5-hexafluoro-2,4-pentanedione) Iron(lII), (HFFAA) induced by gamma rays in dry, air-free toluene solution has been studied; particular emphasis has been placed on the system HFFAA-toluene. HFFAA is reduced radiolytically with G(-chelate) = 1.00, the reduction process apparently involving electron transfer
to the chelate from some species other than free radicals.
TFFAA and FAA are also reduced under the same conditions but at increasingly slower rates; the inequality G(-FAA) < G(-TFFAA) < G(-HFFAA) is explained on the basis of an electron-withdrawing effect by the ligand trifluoromethyl groups.
It was found that G(H2) = 0.13 ±0.03 for toluene in the presence and absence of HFFAA. The G(CH4) = 0.008 is slightly increased in the presence of HFFAA. In HFFAA-toluene solutions, G(dibenzyl) = 0.307 ±0.026 and in
toluene alone, G(dibenzyl) = 0.102 ±0.019. An explanation is offered to account for this increase and for the nature of the species involved in reduction of HFFAA. Activation energies are obtained for processes responsible for the observed radiolysis products.