Group 10 and 11 Transition Metal-Dinitrogen Complexes

Group 10 and 11 transition metals are uniquely placed in the d-block elements as their electronegativities position these metals at the border of classic ligand field theory and the more covalent interactions typical of the p-block elements. The greater electronegativity as compared to that of the earlier transition metals is expected to afford weaker interactions with dinitrogen, and the isolation of such adducts is challenging if possible. The number of reported metal–dinitrogen complexes in these groups is expected to be scarce as the electronegativity correlates with decreased π-backdonation to a N2 ligand. Such metal–ligand π-interactions are considered essential for generating isolable metal–dinitrogen species as well as affording significant activation of the N≡N multiple bond. Despite these challenges, such compounds have been synthesized by the careful selection of ancillary ligands on the metal center, with aspects such as ligand electronic effects, steric constraints, and metal oxidation “states” proving critical. Details on the extent of activation of the dinitrogen fragment as a function of ligand type will be highlighted, with focus on their structure and reactivity relationships. In addition, the downstream reactivity of the dinitrogen adducts will be discussed insofar as the reactivity reports on the properties of the metal–N2 adduct.