Methane Formation by Reaction of a Methyl Thioether with a Photo-Excited Nickel Thiolate—A Process Mimicking Methanogenesis in Archaea
作者:Luca Signor、Carola Knuppe、Robert Hug、Bernd Schweizer、Andreas Pfaltz、Bernhard Jaun
DOI:10.1002/1521-3765(20001002)6:19<3508::aid-chem3508>3.3.co;2-n
日期:2000.10.2
The formation of a sulfuranyl radical intermediate followed by methyl transfer to the nickel(I) center of coenzyme F430 and generation of the disulfide has been proposed as a possible mechanism for the formation of methane catalyzed by methyl coenzyme M reductase in methanogenic archaea. In order to test this hypothesis, a sterically shielded, bifunctional model substrate that contained a methyl thioether
已提出形成硫代烷基自由基中间体,然后将甲基转移至辅酶F430的镍(I)中心并生成二硫键,作为在产甲烷古菌中由甲基辅酶M还原酶催化形成甲烷的可能机理。为了检验该假设,合成了一种空间屏蔽的双功能模型底物,该底物包含甲基硫醚和巯基官能团,可以根据假定的机理形成五元环硫烷基。相应的硫醇盐与Ni(II)盐反应生成抗磁性的方形Ni(II)二硫醇盐络合物,其特征在于X射线衍射。用波长大于300 nm的光照射该配合物后,形成甲烷和环状二硫化物,而在不存在镍的情况下照射硫醇盐只会产生痕量的甲烷,而不会产生环状二硫化物。观察到的产物与通过硫烷基的推测机理相一致,并且光的作用被解释为在激发二硫代镍(II)的电荷转移带时形成了Ni(I)/噻吩基对。在大量过量的硫醇盐存在下,抗磁性络合物转变为顺磁性的五或六配位络合物,与方形平面的抗磁性二硫醇盐相比,事实证明该化合物在甲烷和环状二硫化物的生成中更具活性。 。光的作用