Bis‐Cyclometallated Iridium(III) Complexes with Bidentate Ligands Containing One or Two Pyridylideneamine (PYE) Donors: Influence of PYE Substitution (para or ortho) on Complexation

Abstract

Six pyridylideneamine (PYE)‐containing bidentate ligands and their bis‐cyclometallated Ir(III) complexes have been synthesised and fully characterised. The PYE groups show a contribution from a neutral imine resonance form and a zwitterionic pyridinium form. NMR spectroscopy of the para‐substituted ligands and complexes show those with a C6H4 bridging group have the fastest PYE rotation. X‐ray crystallography of p‐1 and p‐3 shows the PYE N‐donor is trigonal planar whereas for the ortho‐complexes it is more pyramidalized implying an increased contribution of the zwitterionic resonance form for the ortho‐complexes.

Monoanionic Quasi-Imido Ligands Based on 1-Methyl-4-iminopyridine and Complexes with the Main Group Elements Mg, Al, and Zn

“…Our group has previously reported the synthesis of a neutral quasi-amido ligand ([NQA] = MeNC 5 H 4 N i Pr), with the conventional name N -(1-isopropyl p yridin-4­(1 H )- y lid e ne)­amine (PYE), and explored its chemistry in C–F activation and C–H bond functionalization. − The donor properties based on the [NQA]­Rh­(CO) 2 Cl ν CO stretching frequency are comparable to that of NHC ligands, as shown on the right side of Scheme . , To date, a large number of related ligand–metal complexes have seen applications in catalysis and as photosensitizers. − …”