Coordination and Activation of N2 at Low‐Valent Magnesium using a Heterobimetallic Approach: Synthesis and Reactivity of a Masked Dimagnesium Diradical**

Abstract The activation of dinitrogen (N 2 ) by transition metals is central to the highly energy intensive, heterogeneous Haber–Bosch process. Considerable progress has been made towards more sustainable homogeneous activations of N 2 with d‐ and f‐block metals, though little success has been had with main group metals. Here we report that the reduction of a bulky magnesium(II) amide [( TCHP NON)Mg] ( TCHP NON=4,5‐bis(2,4,6‐tricyclohexylanilido)‐2,7‐diethyl‐9,9‐dimethyl‐xanthene) with 5 % w/w K/KI yields the magnesium‐N 2 complex [{K( TCHP NON)Mg} 2 (μ‐N 2 )]. DFT calculations and experimental data show that the dinitrogen unit in the complex has been reduced to the N 2 2− dianion, via a transient anionic magnesium(I) radical. The compound readily reductively activates CO, H 2 and C 2 H 4 , in reactions in which it acts as a masked dimagnesium(I) diradical.