Synthesis, Structures and Comparison of Neutral Complexes Formed by2‐(2′‐Pyridyl)indole and d 6 Transition Metals

2‐(2′‐Pyridyl)indole acts as an N,N‐bidentate ligand when deprotonated and forms (1‐amido‐4‐imine)metallacycles with Re I , Ru II , Rh III and Ir III . The crystal structures of 2‐(2′‐pyridyl)indole and the complexes [Re(C 13 H 9 N 2 )(CO) 2 (PPh 3 ) 2 ], [Ru(C 13 H 9 N 2 )(η 6 ‐C 6 Me 6 )Cl], [Rh(C 13 H 9 N 2 )(η 5 ‐C 5 Me 5 )Cl] and [Ir(C 13 H 9 N 2 )(η 5 ‐C 5 Me 5 )Cl] are presented and their spectra discussed. This provides a foundation for the increased use of this ligand, which is a prototype of a monoanionic, bidentate N,N‐chelating ligand. The introduction of negatively charged N,N‐bidentate ligands can increase the possibility of synthesising complexes tailored to catalysis and other applications. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)