Acid-assisted hydrogenation of CO to methanol using Ru(II) and Rh(III) RAPTA-type catalysts under mild conditions.

A highly efficient homogeneous catalyst system for production of CH3OH from CO2 using single molecular defined ruthenium and rhodium RAPTA-type catalysts [Ru(η6-p-cymene)X2(PTA)] (X = I(1), Cl(2); PTA = 1,3,5-triaza-7-phosphaadamantane) and rhodium catalysts [Rh(η5-C5Me5)X2(PTA/PTA-BH3)] (X = Cl(3), H(4) and PTA-BH3, H(5)) developed in acidic media under mild conditions. A TON of 4752 is achieved using a [Ru(η6-p-cymene)I2(PTA)] catalyst which represents the first example of CO2 hydrogenation to CH3OH using single molecular defined Ru and Rh RAPTA-type catalysts.

Switching Site Reactivity in Hydrogenase Model Systems by Introducing a Pendant Amine Ligand.

Hydrogenases are versatile enzymatic catalysts with an unmet hydrogen evolution reactivity (HER) from synthetic bio-inspired systems. The binuclear active site only has one-site reactivity of the distal Fe atom. Here, binuclear complexes [Fe(CO)(μ-Mebdt)(P(4-CHOCH))] and [Fe(CO)(μ-Mebdt)(PPhPy)] are presented, which show electrocatalytic activity in the presence of weak acids as a proton source for the HER.

Electrocatalytic CO Reduction with a Half-Sandwich Cobalt Catalyst: Selectivity towards CO.

We present herein a Cp*Co(III)-half-sandwich catalyst system for electrocatalytic CO reduction in aqueous acetonitrile solution. In addition to an electron-donating Cp* ligand (Cp*=pentamethylcyclopentadienyl), the catalyst featured a proton-responsive pyridyl-benzimidazole-based N,N-bidentate ligand. Owing to the presence of a relatively electron-rich Co center, the reduced Co(I)-state was made prone to activate the electrophilic carbon center of CO .

Intramolecular stabilization of a catalytic [FeFe]-hydrogenase mimic investigated by experiment and theory.

The mono-substituted complex [Fe2(CO)5(μ-naphthalene-2-thiolate)2(P(PhOMe-p)3)] was prepared taking after the structural principles from both [NiFe] and [FeFe]-hydrogenase enzymes. Crystal structures are reported for this complex and the all carbonyl analogue. The bridging naphthalene thiolates resemble μ-bridging cysteine amino acids.

Hydrogen generation: aromatic dithiolate-bridged metal carbonyl complexes as hydrogenase catalytic site models.

The design, syntheses and characteristics of metal carbonyl complexes with aromatic dithiolate linkers reported as bioinspired hydrogenase catalytic site models are described and reviewed. Among these the complexes capable of hydrogen generation have been discussed in detail. Comparisons have been made with carbonyl complexes having alkyl dithiolates as linkers between metal centers.