Linked bis(.mu.-phosphido) and related ligands for metallic clusters. 1. Application to the hexacarbonyldiiron moiety

Electrochemical proton reduction at mild potentials by monosubstituted diiron organometallic complexes bearing a benzenedithiolate bridge

“…This points to a structure for 1 2À in which one Fe-S bond is cleaved and one CO is in a bridging position [29], liberating an available site on the iron ion for ligand binding (here P(OMe) 3 ). Hence, there is most certainly an uptake of an available phosphite ligand by the dianion 1 2À , followed by a loss of CO (Eq.…”

Electrochemical proton reduction by thiolate-bridged hexacarbonyldiiron clusters

“…In contrast, a value of I a p =I c p $ 0:45 at 0.5 V s À1 was reported for the reduction of Fe 2 (l-SC 3 H 6 S)(CO) 6 [34], emphasizing the strong stabilization of the reduced form of the Fe 2 (S 2 R)(CO) 6 derivatives by the toluenedithiol bridge. On the other hand, the chemical reduction of 1 by sodium naphthalenide yielded the stable dianion 1 2À [40], suggesting that the single reduction wave observed in Fig. 1 corresponds to a two-electron process.…”

Activation of proton by the two-electron reduction of a di-iron organometallic complex

“…Fe 2 (bdt)(CO) 6 (1) does not react with acid in organic solvent [14,17,18]. However, the addition of a relatively strong acid such as HOTs (pK a $ 8 in CH 3 CN) to a solution of complex 1 in CH 3 CN + Bu 4 NPF 6 electrolyte triggers the appearance of a new reduction wave noted B in Fig.…”

“…However McKennis and Kyba [17] reported that the IR spectrum of a solution of 1 in THF shows after treatment with excess sodium an adsorption band at 1660 cm À1 in a region characteristic of a bridging carbonyl for an anionic compound. A possibility to explain this spectroscopic feature is to consider that one of the two Fe-S bonds in complex 1 is cleaved upon reduction [17]. Accordingly, there will be two proton binding sites in the dianion 1 2À , namely one of the two S atoms and one of the two Fe atoms.…”

“…Fe 2 (bdt)(CO) 6 (1) was prepared by literature methods [17,18]. The syntheses were carried out under an inert atmosphere using the standard Schlenk techniques.…”