Iridium complexes containing N-donor-functionalized η1-fluorenyl ligands

Iridium complexes of two different nitrogen-donor-functionalized fluorenyl ligands have been synthesized and characterized, L1Ir(COD) and L2Ir(COD), where L1− = [9-(2-dimethylamino)ethyl]fluorenyl anion, L2− = [9-(2-ortho-pyridyl)ethyl]fluorenyl anion, and COD = 1,5-cyclooctadiene. The structures of both ligands (in their protonated form) and of both complexes were determined by single-crystal X-ray crystallography. Structural consequences of the nature of the nitrogen ligand (dimethylamino substituent versus ortho-pyridyl substituent) are significantly different Ir–N distances (shorter for L2Ir(COD)) and indirect cis-influence on the COD ligand resulting in a shorter Ir–olefin bond cis to the nitrogen donor in L2Ir(COD). Both complexes act as precatalysts for arene hydrogenation.

Graphical abstractIridium complexes of two different nitrogen-donor-functionalized fluorenyl ligands have been synthesized and characterized, L1Ir(COD) and L2Ir(COD), where L1− = [9-(2-dimethylamino)ethyl]fluorenyl anion, L2− = [9-(2-ortho-pyridyl)ethyl]fluorenyl anion, and COD = 1,5-cyclooctadiene. The structures of both ligands (in their protonated form) and of both complexes were determined by single-crystal X-ray crystallography. Both complexes act as precatalysts for arene hydrogenation.Figure optionsDownload full-size imageDownload as PowerPoint slide