Halide-induced disproportionation of triiron dodecacarbonyl to form the radical anion [Fe3(CO)11].bul.- and its characterization by single-crystal x-ray diffraction

Mechanistic Study of the Phase-Transfer-Catalyzed Reduction of Nitrobenzene to Aniline by Iron Carbonyl Complexes. Role of the Radical Anion [Fe3(CO)11]•-

“…As we have shown that 5 is probably an intermediate in the generation of 7 from 1 and since we have previously shown that 5 reacts with nitroarenes at a faster rate than 7, 19 it is possible that 5 is trapped by PhNO 2 before it can react with 1. We also recall that the reaction of 5 with PhNO 2 generates 7 in the early stages of the reaction.…”

“…26 We can now wonder which is the mechanism by which 7 is formed from 1 and hydroxide anion. The formation of variable amounts of Fe(CO) 5 (4) in all reactions involving chloride as the active reagent, 19 but not in the reactions with OH -ion, 27 indicates a different mechanism for the latter. We now recall that the first method to be reported for the synthesis of 7 involved the (24) (a) Whitmire, K.; Ross, J.; Cooper, C. B. III; Schriver, D. F. Inorg.…”

“…The formation of 9 is not surprising, since decomposition of 7 in solution is known to afford this product. 19 As the long reaction times required when toluene is used as solvent may lead to the decomposition of reactive compounds such as 7 and the precipitation of several products makes it difficult to follow the development of the reaction, we repeated the same reactions using THF as the organic solvent.…”

“…19,20 The surprising finding is that 7 not only is stable in the presence of large amounts of water but can also be generated by the action of hydroxide anion. As already mentioned, formation of 8 during the base-promoted decomposition of 7 may be partially derived from trace amounts of oxygen.…”

“…We also recall that the reaction of 5 with PhNO 2 generates 7 in the early stages of the reaction. 19,30 Several experiments were performed, even inverting the addition of PhNO 2 and NaOH/H 2 O. Unambiguous evidence for an active role of 5 could not be obtained, but a mixture of 7 and 4 was immediately formed even when the order of addition of the reagents was reversed, confirming the active role of 7 in the reduction.…”