Single molybdenum atom anchored on 2D Ti2NO2 MXene as a promising electrocatalyst for N2 fixation

Mo anchored on Ti2NO2 (Mo/Ti2NO2) surface possesses superior NRR performance, with an overpotential ηNRR of 0.16 V via enzymatic mechanism.

Shared function and moonlighting proteins in molybdenum cofactor biosynthesis

The biosynthesis of the molybdenum cofactor (Moco) is a highly conserved pathway in bacteria, archaea and eukaryotes. The molybdenum atom in Moco-containing enzymes is coordinated to the dithiolene group of a tricyclic pyranopterin monophosphate cofactor. The biosynthesis of Moco can be divided into three conserved steps, with a fourth present only in bacteria and archaea: (1) formation of cyclic pyranopterin monophosphate, (2) formation of molybdopterin (MPT), (3) insertion of molybdenum into MPT to form Mo-MPT, and (4) additional modification of Mo-MPT in bacteria with the attachment of a GMP or CMP nucleotide, forming the dinucleotide variants of Moco. While the proteins involved in the catalytic reaction of each step of Moco biosynthesis are highly conserved among the Phyla, a surprising link to other cellular pathways has been identified by recent discoveries. In particular, the pathways for FeS cluster assembly and thio-modifications of tRNA are connected to Moco biosynthesis by sharing the same protein components. Further, proteins involved in Moco biosynthesis are not only shared with other pathways, but additionally have moonlighting roles. This review gives an overview of Moco biosynthesis in bacteria and humans and highlights the shared function and moonlighting roles of the participating proteins.

Identification of a spin-coupled Mo(iii) in the nitrogenase iron–molybdenum cofactor

The molybdenum atom in FeMoco is imperative to the high activity of the enzyme and has been proposed to be Mo(iv). We demonstrate that only Mo(iii) fits Mo HERFD XAS data, the first example of Mo(iii) in biology. Theoretical calculations further reveal an unusual spin-coupled Mo(iii).

Synthesis, Structure and Reactivity of the Molybdenum Cycloheptatrienyl Tetrahydroborate Complex {(η7-C7H7)Mo(η2-BH4)[P(cyclo-C6H11)3]}

The reaction of the cycloheptatrienyl-toluene sandwich complex [(η7-C7H7)Mo(η6- C6H5Me)]BF4 with tricyclohexylphosphine in acetonitrile furnishes the cationic half-sandwich cycloheptatrienyl complex {(η7-C7H7)Mo[P(C6H11)3](CH3CN)2}BF4 (1). Treatment of 1 with NaBH4 in ethanol results in the formation of the tetrahydroborate complex {(η7-C7H7)Mo(η2- BH4)[P(cyclo-C6H11)3]} (2), in which the borohydride ligand is coordinated to the molybdenum atom through two three-center, two-electron bonds. The complex is stable in ethanol and water. The expected formation of a metal trihydride of the type {(η7-C7H7)MoH3[P(cyclo-C6H11)3]} as a hydrolysis product could not be observed. Since this behaviour differs from the reactivity reported for related cyclopentadienyl-ruthenium complexes, a comparative computational study on the model complexes [(η5-C5Me5)RuH3(PMe3)] (4) and [(η7-C7H7)MoH3(PMe3)] (5) was performed revealing that the classical trihydride form [MH3] represents the global minimum for the ruthenium complex 4, whereas the dihydrogen-hydride form [MH(η2-H2)] is more stable for the molybdenum counterpart.