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

Angew Chem Int Ed Engl. 2019 Aug 12;58(33):11279-11284. doi: 10.1002/anie.201905299. Epub 2019 Jul 8.

Abstract

Reported here is the N2 cleavage of a one-electron oxidation reaction using trans-[Mo(depe)2 (N2 )2 ] (1) (depe=Et2 PCH2 CH2 PEt2 ), which is a classical molybdenum(0)-dinitrogen complex supported by two bidentate phosphine ligands. The molybdenum(IV) terminal nitride complex [Mo(depe)2 N][BArf4 ] (2) (BArf4 =B(3,5-(CF3 )2 C6 H3 )4 ) is synthesized by the one-electron oxidation of 1 upon addition of a mild oxidant, [Cp2 Fe][BArf4 ] (Cp=C5 H5 ), and proceeds by N2 cleavage from a MoII -N=N-MoII structure. In addition, the electrochemical oxidation reaction for 1 also cleaved the N2 ligand to give 2. The dimeric Mo complex with a bridging N2 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 MoI species is converted into 2 via the dimeric structure involving a zigzag transition state.

Keywords: dinitrogen; molybdenum; oxidation; reaction mechanisms; structure elucidation.