Aminocarbyne ligands in organometallic chemistry

Following the former synthetic work on group 6 metal complexes, aminocarbyne (aminoalkylidyne) ligands have become popular across various transition metal groups. They are versatile ligands adapting to variable coordination modes (i.e. terminal, bridging and multibridging), metal oxidation states and co-ligands. They possess peculiar structural and reactivity features compared to nitrogen-lacking alkylidyne ligands and, especially when bridging coordinated to diiron bis-cyclopentadienyl frames, exhibit a rich chemistry enabling the construction of unusual organometallic species. The bonding, electronic and steric effects, structural and spectroscopic features and reactivity trends of aminocarbyne ligands are reviewed with reference to the distinct cases (nuclearity of the complex and coordination mode, nature of the metal element, and type of substituent(s) on the aminocarbyne).