According to the well-accepted mechanism, methyl-coenzyme M reductase (MCR) involves Ni-mediated thiolate-to-disulfide conversion that sustains its catalytic cycle of methane formation in the energy saving pathways of methanotrophic microbes. Model complexes that illustrate Ni-ion mediated reversible thiolate/disulfide transformation are unknown. In this paper we report the synthesis, crystal structure, spectroscopic properties and redox interconversions of a set of NiII complexes comprising a tridentate N2 S donor thiol and its analogous N4 S2 donor disulfide ligands. These complexes demonstrate reversible NiII -thiolate/NiII -disulfide (both bound and unbound disulfide-S to NiII ) transformations via thiyl and disulfide monoradical anions that resemble a primary step of MCR's catalytic cycle.

中文翻译：

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镍（II）介导的可逆的硫氰酸盐/二硫化物转化，模拟了甲基辅酶M还原酶催化循环的关键步骤。

根据公认的机制，甲基辅酶M还原酶（MCR）涉及Ni介导的硫醇盐到二硫化物的转化，从而在甲烷营养化微生物的节能途径中维持甲烷形成的催化循环。说明Ni离子介导的可逆硫醇盐/二硫键转化的模型配合物是未知的。在本文中，我们报告了一组NiII配合物的合成，晶体结构，光谱性质和氧化还原互变，该配合物包括三齿N2 S供体硫醇及其类似的N4 S2供体二硫配体。这些配合物通过巯基和二硫化物单自由基阴离子显示出可逆的NiII-硫醇盐/ NiII-二硫化物（结合和未结合的二硫化物-S到NiII）转变，类似于MCR催化循环的第一步。