ABSTRACT
The Moâ nitrogenase catalyzes the ambient reduction of N2 to NH3 at its M-cluster site. A complex metallocofactor with a core composition of [MoFe7 S9 C], the M-cluster, can be extracted from the protein scaffold and used to facilitate the catalytic reduction of CN- , CO, and CO2 into hydrocarbons in the isolated state. Herein, we report the synthesis, structure, and reactivity of an asymmetric M-cluster analogue with a core composition of [MoFe5 S9 ]. This analogue, referred to as the Mo-cluster, is the first synthetic example of an M-cluster mimic with Fe and Mo positioned at opposite ends of the cluster. Moreover, the ability of the Mo-cluster to reduce C1 substrates to hydrocarbons suggests the feasibility of developing nitrogenase-based biomimetic approaches to recycle C1 â waste into fuel products.
Subject(s)
Bacteria/enzymology , Biomimetic Materials/chemistry , Coenzymes/chemistry , Molybdenum/chemistry , Molybdoferredoxin/chemistry , Nitrogenase/chemistry , Bacteria/chemistry , Biomimetic Materials/chemical synthesis , Biomimetics , Carbon Dioxide/chemistry , Carbon Monoxide/chemistry , Coenzymes/chemical synthesis , Models, Molecular , Molybdoferredoxin/chemical synthesis , Nitrogenase/chemical synthesis , Oxidation-ReductionSubject(s)
Iron-Sulfur Proteins/chemistry , Iron/chemistry , Nitrogenase/chemistry , Organometallic Compounds/chemistry , Protons , Sulfur/chemistry , Iron-Sulfur Proteins/chemical synthesis , Kinetics , Molecular Conformation , Nitrogenase/chemical synthesis , Organometallic Compounds/chemical synthesisABSTRACT
The [8Fe-7S] core of the P-clusters in nitrogenases is unique among the known [Fe-S] clusters which are essential to electron-transfer processes in nature. The [8Fe-7S] cluster has been thought unstable and to exist only in protein environments. We found that this unusual [8Fe-7S] structure can be self-assembled from the reaction of Fe(II) bis-amide, tetramethylthiourea, 2,4,6-triisopropylbenzenethiol, and elemental sulfur in a specific mole ratio. The structure of the complex isolated therefrom closely resembles that of the reduced form (PN) of the P-clusters, while the 6Fe(II)2Fe(III) oxidation state was manifested by the Mössbauer study.
Subject(s)
Iron/chemistry , Nitrogenase/chemical synthesis , Sulfur/chemistry , Ferrous Compounds/chemistry , Models, Molecular , Nitrogenase/chemistry , Nitrogenase/metabolism , Spectroscopy, MossbauerABSTRACT
There exist a limited but growing number of biological metal centers whose properties lie conspicuously outside the realm of known inorganic chemistry. The synthetic analogue approach, broadly directed, offers a powerful exploratory tool that can define intrinsic chemical possibilities for these sites while simultaneously expanding the frontiers of fundamental inorganic chemistry. This speculative application of analogue study is exemplified here in the evolution of synthetic efforts inspired by the cluster chemistry of biological nitrogen fixation.
