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Synthesis, Structure, and Photophysical and Electrochemical Properties of Cyclometallated Iridium( III ) Complexes with Phenylated Bipyridine Ligands
Author(s) -
Lepeltier Marc,
KwokMing Lee Terence,
KamWing Lo Kenneth,
Toupet Loic,
Le Bozec Hubert,
Guerchais Véronique
Publication year - 2005
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200400418
Subject(s) - diimine , chemistry , iridium , pyridine , ligand (biochemistry) , excited state , photochemistry , dihedral angle , cationic polymerization , crystallography , bipyridine , electrochemistry , chromophore , luminescence , phosphorescence , stereochemistry , fluorescence , medicinal chemistry , crystal structure , polymer chemistry , hydrogen bond , molecule , organic chemistry , electrode , receptor , biochemistry , nuclear physics , catalysis , physics , optoelectronics , quantum mechanics
A series of cationic diiminoiridium( III ) complexes [Ir(ppy‐ N , C ) 2 (L‐ N , N )](PF 6 ) has been prepared [Hppy = 2‐phenylpyridine; L = 4,4′‐ t Bu 2 dpbpy ( 1 ), 4,4′‐Me 2 dpbpy ( 2 ), 4,4′‐Me 2 pbpy ( 3 ), 4,4′‐Me 2 bpy ( 4 )] and their photophysical and electrochemical properties studied. X‐ray diffraction studies of complex 1 reveal a dihedral angle of about 33° between the pyridine rings, and that the two phenyl groups are also tilted with respect to the adjacent pyridine rings. All the complexes exhibit moderately intense and long‐lived emission. The origin of the emission is tentatively assigned to a triplet metal‐to‐ligand charge‐transfer 3 MLCT [dπ(Ir) → π*(diimine)] excited state, although the possibility of a triplet σ‐bond‐to‐ligand charge transfer 3 SBLCT [σ(Ir−C) → π*(diimine)] cannot be excluded. The luminescence properties of the complexes are dependent on the substituents on the diimine ligands. Selective N ‐methylation of the diimine ligands has been achieved and their N , C ‐coordination to the Ir centre has been attempted. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)