Extremely bulky amide ligands in main group chemistry

The search for extremely sterically demanding monodentate amide ligands to access main group complexes in low-coordination numbers and highly reactive bonding modes is an area of intense research interest. The recent development of three classes of sterically demanding, monodentate amide ligands - the m-terphenyl anilides [N(R){C6H3Ar2-2,6}](-) (Ar = aryl, R = H, methyl, silyl), substituted carbazol-9-yl and the extremely bulky amides [N(R)(Ar')](-) (Ar' = 2,6-{C(H)Ph-2}-4-R'-C6H2, R = silyl, aryl, silyloxy, R' = alkyl) is facilitating the isolation of stable species with new coordination modes for the main group elements. These compounds are of fundamental importance not only from the investigation of their structure and bonding, but also the investigation of their reactivity highlights the potential for small molecule activation chemistry under mild conditions and applications in catalysis. This review reports on the recent developments for these compounds with emphasis on their synthesis, structure and reactivity.