Synthesis and characterization of the diiron biomimics bearing phosphine borane for hydrogen formation

Diiron Complexes [Fe2(CO)5(μ‐pdt/Mebdt)(L)] Containing a Chelating Diphosphine Ligand L=(Oxydi‐2,1‐phenylene)bis(diphenylphosphine): Bioinspired [FeFe] Hydrogenase Model Complexes

“…The complexes displayed absorption bands in the range 2100–1900 cm ‐1 in dichloromethane corresponding to the terminal coordination of the carbonyl (CO) groups. The ν CO bands were shifted towards lower wavenumbers by about 70 cm ‐1 in comparison to the hexacarbonyl precursor complexes and were similar to those observed for analogous phosphine substituted complexes This is because the attachment of electron‐rich diphosphine ligand increases the electron density on the Fe(I)Fe(I) centers.…”

Proton Relay Effects in Pyridyl‐Appended Hydrogenase Mimics for Proton Reduction Catalysis

“…The redox potentials of the evolving species are found to be consistent with those of the bis‐substituted complexes 1b – 3b , suggesting that ligand exchange might take place upon reduction. Such reactivity has been suggested for the mono‐substituted bis‐diphenylphosphinomethane (dppm) di‐iron complex; its electrochemical reduction induces a disproportionation reaction associated with intramolecular rearrangement to the chelating diphosphane derivative following CO dissociation . Figure shows that for complex 1a , when consecutive voltammograms are recorded without refreshing the solution at the working electrode, a third reduction event appears at –1.50 V, which coincides with a redox potential of hexacarbonyl species 1 , as shown by a spiking experiment with an authentic sample of 1 (Figure S40).…”

Coordination and Dehydrogenation of Diphosphine–Borane Ph2PCH2PPh2·BH3 at a Heterometallic MoRe Center to Give an Agostic Boryl-Bridged Derivative

“…Indeed, previous work has shown that the dppm·BH 3 ligand can form different mononuclear complexes by using the lone electron pair of its “free” P atom (the trivial κ 1 -mode) and additionally one or two B–H bonds (κ 1 ,η 2 - and κ 1 ,η 3 -modes, Chart ). − Incidentally, we note that only one binuclear complex with this ligand appears to have been reported previously (a Fe 2 complex with a conventional κ 1 -bound ligand) . In addition, we note that the relatively weak interaction of B–H bonds with metal atoms in the agostic κ 1 ,η 2 - and κ 1 ,η 3 -modes enables dppm·BH 3 to act as a hemilabile ligand, able to provide, by decoordination of B–H bonds, vacant coordination sites useful in catalytic processes .…”