An S‐Oxygenated [NiFe] Complex Modelling Sulfenate Intermediates of an O₂‐Tolerant Hydrogenase

Abstract

To understand the molecular details of O -tolerant hydrogen cycling by a soluble NAD -reducing [NiFe] hydrogenase, we herein present the first bioinspired heterobimetallic S-oxygenated [NiFe] complex as a structural and vibrational spectroscopic model for the oxygen-inhibited [NiFe] active site. This compound and its non-S-oxygenated congener were fully characterized, and their electronic structures were elucidated in a combined experimental and theoretical study with emphasis on the bridging sulfenato moiety. Based on the vibrational spectroscopic properties of these complexes, we also propose novel strategies for exploring S-oxygenated intermediates in hydrogenases and similar enzymes.

Oxygen uptake in complexes related to [NiFeS]- and [NiFeSe]-hydrogenase active sites

“…However, no oxygenated sulfur species were reported from their system. The first S-oxygenated [NiFe] complex was reported by Driess's lab as a model for sulfenate intermediates in O 2 -tolerant hydrogenase; it was synthesized from FeBr 2 and the pre-formed sulfenato nickel complex17 rather than direct oxygenation 18…”

Comprehensive reaction mechanisms at and near the Ni–Fe active sites of [NiFe] hydrogenases

“…Related to the reversible sulfoxygenation mechanism, Lindenmaier et al reported the first sulfoxygenated heterobimetallic [NiFe] complex as a structural model for the sulfoxygenated active site of [NiFe] H 2 ases 154. …”

A Computational Determination of the Origins of Diastereoselective Alkylations of a Cysteinesulfenate Anion

“…The participation of the sulfenate oxygen in H‐bonding is well recognized. [2b], [2d], [5b], However, internal complexation of the lithium counterion would appear to provide a competitive or even superior stabilization mode for these entities, at least in the environment modeled here.…”