This Feature Article describes recent advances in the design of multinucleating ligands that support small molecule activation chemistry.

Dicobalt complexes supported by flexible macrocyclic ligands were used to target the generation of the bridging nitrido species [( PDI )Co (μ-N)(PMe ) ] (PDI=2,6-pyridyldiimine; n=2, 3, corresponding to the number of catenated methylene units between imino nitrogen atoms). Depending on the size of the macrocycle and the reaction conditions (solution versus solid-state), the thermolysis of azide precursors yielded bridging phosphinimido [( PDI )Co (μ-NPMe )(PMe ) ] , amido [( PDI )Co (μ-NH )(PMe ) ] (n=2, 3), and C-H amination [( PDI *-μ-NH)Co (PMe ) ] products. All results are consistent with the initial formation of [( PDI )Co (μ-N)(PMe ) ] , followed by 1) PMe attack on the nitride, 2) net hydrogen-atom transfer to form N-H bonds, or 3) C-H amination of the alkyl linker of the PDI ligand.