Mechanism for the Reaction of CO with Oxorhenium Hydrides: Migratory Insertion of CO into Rhenium Hydride and Formyl Bonds leads to Migration from Rhenium to the Oxo Ligand

Oxidation-induced coupling reactions of bi(metallacycloprop-1-ene) complexes

The feasibility of coupling of two carbene ligands of biscarbene complexes LnM(CR2)2 to form alkene complexes LnM(η2-R2CCR2) was predicted theoretically as early as 1982. However, until now, there appear still no reports on carbene coupling reactions of well-defined biscarbene complexes. This work reports oxidation-induced coupling reactions of bi(metallacycloprop-1-ene) complexes to give η4-butadiene complexes, a unique example of coupling of two carbene ligands of biscarbene complexes.

Comparative Study of the Thermal Stabilities of the Experimentally Known High-Valent Fe(IV) Compounds Fe(1-norbornyl)4 and Fe(cyclohexyl)4

The high stability of the experimentally known homoleptic 1-norbornyl derivative (nor)₄Fe of iron in the unusual +4 oxidation state is a consequence of the high reaction barriers of the singlet or triplet potential surfaces constrained by the global dispersion attraction and the great steric demands of the norbornyl groups. The much more limited stability of the corresponding cyclohexyl derivative (cx)₄Fe may result from the conical intersection between the singlet potential surface and the quintet spin potential surface arising from the weaker dispersion attraction and the reduced steric effect of the cyclohexyl groups relative to the 1-norbornyl groups. In contrast, the high stability of the likewise experimentally known (cx)₄M (M = Ru or Os) structures results from the larger ligand field splitting (Δ) of the d-orbital energies for the second and third-row transition metals ruthenium and osmium relative to that of the first-row transition metal iron. The cyclohexyl derivative (cx)₄Fe is predicted to be reactive toward carbon monoxide to insert CO into up to two Fe-C bonds. However, the dispersion effect as well as the much larger size of the 1-norbornyl substituents prevents similar reactivity of (nor)₄Fe with carbon monoxide.

Synthesis and reactivity of nitridorhenium complexes incorporating the mercaptoethylsulfide (SSS) ligand

A method for the preparation of nitridorhenium(v) complexes of the form (SSS)Re(N)(L) (where SSS = 2-mercaptoethylsulfide and L = PPh₃ and t-BuNC) has been described. These complexes react with Lewis acids allowing for the isolation of adducts. The lack of a significant steric profile on the SSS ligand combined with enhanced nucleophilicity of the nitrido group does not allow for the effective formation of frustrated Lewis pairs with these complexes and as a result these species are poor catalysts for the hydrogenation of unactivated olefins.

A unique formyl iodoargentate exhibiting luminescent and photocurrent response properties

A unique formyl iodoargentate contains an unprecedented CHO⁻ link mode, which exhibits luminescent and photocurrent response properties.

CO Reduction to CH3OSiMe3: Electrophile-Promoted Hydride Migration at a Single Fe Site

One of the major challenges associated with developing molecular Fischer-Tropsch catalysts is the design of systems that promote the formation of C-H bonds from H₂ and CO while also facilitating the release of the resulting CO-derived organic products. To this end, we describe the synthesis of reduced iron-hydride/carbonyl complexes that enable an electrophile-promoted hydride migration process, resulting in the reduction of coordinated CO to a siloxymethyl (L_nFe-CH₂OSiMe₃) group. Intramolecular hydride-to-CO migrations are extremely rare, and to our knowledge the system described herein is the first example where such a process can be accessed from a thermally stable M(CO)(H) complex. Further addition of H₂ to L_nFe-CH₂OSiMe₃ releases CH₃OSiMe₃, demonstrating net four-electron reduction of CO to CH₃OSiMe₃ at a single Fe site.