Towards Structural-Functional Mimics of Acetylene Hydratase: Reversible Activation of Acetylene using a Biomimetic Tungsten Complex

摘要

The synthesis and characterization of a biomimetic system that can reversibly bind acetylene (ethyne) is reported. The system has been designed to mimic catalytic intermediates of the tungstoenzyme acetylene hydratase. The thiophenyloxazoline ligand S-Phoz (2-(4,4-dimethyloxazolin-2-yl)thiophenolate) is used to generate a bioinspired donor environment around the Wcenter, facilitating the stabilization of W-acetylene adducts. The featured complexes [W(C2H2)(CO)(S-Phoz)(2)] (2) and [WO(C2H2)(S-Phoz)(2)] (3) are extremely rare from a synthetic and structural point of view as very little is known about W-C2H2 adducts. Upon exposure to visible light, 3 can release C2H2 from its coordination sphere to yield the 14-electron species [WO(S-Phoz)(2)] (4). Under light-exclusion 4 re-activates C2H2 making this the first fully characterized system for the reversible activation of acetylene.