Details

Autor(en) / Beteiligte

• Basu, Debashis
• Subasinghe, S. M. Supundrika
• Mankad, Neal P.

Titel

Reactivity of a Dithiocarbamate-Ligated [WVIS] Complex with Hydride Donors: Toward a Synthetic Mimic of Formate Dehydrogenase

Ist Teil von

• Inorganic chemistry, 2023-04, Vol.62 (16), p.6332-6338

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2023

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Formate dehydrogenase (FDH) enzymes catalyze redox interconversion of CO2 and HCO2 –, with a key mechanistic step being the transfer of H– from HCO2 – to an oxidized active site featuring a [MVIS] group in a sulfur-rich environment (M = Mo or W). Here, we report reactivity studies with HCO2 – and other reducing agents of a synthetic [WVIS] model complex ligated by dithiocarbamate (dtc) ligands. Reactions of [WVIS­(dtc)3]­[BF4] (1) conducted in MeOH solvent generated [WVIS­(S2)­(dtc)2] (2) and [WVS­(μ-S)­(dtc)]2 (3) products by a solvolysis pathway that was accelerated by the presence of [Me4N]­[HCO2] but did not require it. Under MeOH-free conditions, the reaction of 1 with [Et4N]­[HCO2] produced some [WIV(μ-S)­(μ-dtc)­(dtc)]2 (4), but predominantly [WV(dtc)4]+ (5), along with stoichiometric CO2 detected by headspace gas chromatography (GC) analysis. Stronger hydride sources such as K-selectride generated the more reduced analogue, 4, exclusively. The reaction of 1 with the electron donor, CoCp2, also produced 4 and 5 in varying amounts depending on reaction conditions. These results indicate that formates and borohydrides act as electron donors rather than hydride donors toward 1, an outcome that diverges from the behavior of FDHs. The difference is ascribed to the more oxidizing potential of [WVIS] complex 1 when supported by monoanionic dtc ligands that allows electron transfer to outcompete hydride transfer, as compared to the more reduced [MVIS] active sites supported by dianionic pyranopterindithiolate ligands in FDHs.