Synthesis and reactivity of side-on-bound dinitrogen metal complexes

An up-to-date account of the Synthesis of side-on-bound dinitrogen complexes of the lanthanides, the actinides, and the transition elements over the past 40 years is given. In addition, the reactivity of these derivatives is summarized. There have been many complicated multinuclear Cluster complexes with the N-2 imbedded in a fashion that corresponds to side-on N-2. There have been some suggestions, as early as 1960. that side-on dinitrogen complexes should exist. However, a key date in this area is 1988, which is when the disamarium Complex (CP*Sm-2)(2)(mu-eta(2):eta(2)-N-2) was reported. It is this date that is used in this account as the real starting point for the area of side-on dinitrogen coordination chemistry. After 1988, side-on dinitrogen complexes are reviewed from the point of view of Synthesis, structure (N-N bond lengths, where applicable), and reactivity. What becomes apparent is that while there have been many new side-on dinitrogen complexes discovered recently, investigations into their reactivity patterns are still at a primitive stage.