Dinitrogen-Molybdenum Complex Induces Dinitrogen Cleavage by One-Electron Oxidation

Reported here is the N-2 cleavage of a one-electron oxidation reaction using trans-[Mo(depe)(2)(N-2)(2)] (1) (depe=Et2PCH2CH2PEt2), which is a classical molybdenum(0)-dinitrogen complex supported by two bidentate phosphine ligands. The molybdenum(IV) terminal nitride complex [Mo(depe)(2)N][BArf(4)] (2) (BArf(4)=B(3,5-(CF3)(2)C6H3)(4)) is synthesized by the one-electron oxidation of 1 upon addition of a mild oxidant, [Cp2Fe][BArf(4)] (Cp=C5H5), and proceeds by N-2 cleavage from a Mo-II-N=N-Mo-II structure. In addition, the electrochemical oxidation reaction for 1 also cleaved the N-2 ligand to give 2. The dimeric Mo complex with a bridging N-2 is detected by in situ resonance Raman and in situ UV-vis spectroscopies during the electrochemical oxidation reaction for 1. Density-functional theory (DFT) calculations reveal that the unstable monomeric oxidized Mo-I species is converted into 2 via the dimeric structure involving a zigzag transition state.