Electron-transfer chemistry of the 20-electron complex bis(hexamethylbenzene)iron(0) [(.eta.6-C6Me6)2Fe(0)] and its strategic role in carbon-hydrogen bond activation and carbon-carbon bond formation

Why is Ferrocene so Exceptional?

“…[158] (5) With 1,1′-diacetylferrocene, only double ring exchange with polymethylbenzene derivatives was achieved, yielding [Fe(arene) 2 ] 2+ salts, a series of complexes isolobal to ferrocene with rich redox and arene activation properties. [159,160] Carbon atoms in one ferrocene ring can also be replaced by heteroatoms, although access does not involve ferrocene. For instance the piano-stool complex [Fe(η 5 -C 5 H 5 )(CO) 2 (η 1 -pyrrole)] is used as a precursor for the synthesis of azaferrocene, [Fe-(η 5 -C 5 H 5 )(η 5 -C 4 H 4 N)], [161] whereas pentaphosphaferrocene, [Fe(η 5 -C 5 Me 5 )(η 5 -P 5 )], was synthesized by a related strategy [162] that has been extended to a large variety of sandwich-type complexes containing the CpFe fragment and to their supramolecular applications.…”

Organoiron activation combined with electron- and proton transfer: implications in biology, organic synthesis, catalysis and nanosciences

“…For instance, regio-and stereospecific sequential double nucleophilic addition onto coordinated benzene in 5 was obtained subsequent to hydride abstraction from 6 via an electron-transfer mechanism when direct hydride abstraction would fail for steric reasons in the related isolobal iron carbonyl series (Scheme 5) [15]. In another strategy, electron transfer from the 20-electron complex 7 to organic halides provided 19-electron analogues that coupled with the resulting organic radicals to give 8 (Scheme 6) [16].…”

High catalytic activity of Rh nanoparticles generated from cobaltocene and RhCl3 in aqueous solution

“…Cobaltocene is a strong reducing agent 22,23 that has recently been used for the reduction of graphene oxide, 24 the generation of H2 25 and the reduction of Au, 26 Pd, 26 Cu 27 and Ag 27 salts to metal NPs. It is an electron-reservoir complex, 28,29 i.e. its redox potential E° (Cp2Co +/0 ) is very negative (-1.4 V vs. SCE or 0.93 V vs. NHE) 22,23 and both its oxidized and reduced forms are thermally robust.…”