Dinitrogen Activation by Group 4 Metal Complexes

Side-on matters: When dinitrogen bridges two Group 4 metal centers in the side-on binding mode, the reactivity of the N2 unit is enhanced, as evidenced by unprecedented reactions with H2, alkynes, silanes, isocyanates, and now carbon dioxide (see scheme). This Highlight summarizes a number of recent breakthroughs in dinitrogen functionalization by bimetallic Group 4 complexes, culminating with the reaction of CO2 with a dihafium dinitrogen derivative.