In:
European Journal of Inorganic Chemistry, Wiley, Vol. 2007, No. 13 ( 2007-05), p. 1911-1919
Abstract:
Three new polypyridine iridium(III) complexes [Ir III Cl(L)(tterpy)](PF 6 ) 2 {L = phen ( 1 ), dpphen ( 2 ), and dmbpy ( 3 )} were prepared. Reference complexes [Ir III Cl(bpy)(tterpy)](PF 6 ) 2 ( 4 ) and [Ir III (L) 2 ](PF 6 ) 3 {L = tterpy ( 5 ) and terpy ( 6 )} were also prepared. Abbreviations of the ligands used here are phen = 1,10‐phenanthroline, dpphen = 4,7‐diphenyl‐1,10‐phenanthroline, bpy = 2,2′‐bipyridine, dmbpy = 4,4′‐dimethyl‐2,2′‐bipyridine, tterpy = 4′‐(4‐tolyl)‐2,2′:6′,2″‐terpyridine, and terpy = 2,2′:6′,2″‐terpyridine. The syntheses, which were accomplished in typical reaction times of fifteen minutes by using a microwave oven, were easier than a previous method. The complexes were characterized by electrospray mass spectrometry, UV/Vis spectroscopy, and cyclic voltammetry (CV). The X‐ray structures of the two complexes 5 and 6 were also obtained. Cyclic voltammograms of all the[Ir III Cl(L)(tterpy)] 2+ complexes showed that the first reduction occurred at around –0.67 V, which is attributed to the reduction of the tterpy ligand in [Ir III Cl(L)(tterpy)] 2+ . The electronic properties of complexes 5 and 6 were studied by using B3LYP functional calculations, and their optimized geometries were compared to those of the experimentally observed ones. Excited triplet and singlet states are also examined by using time‐dependent density functional theory (TDDFT). The calculated energies of the lowest singlet and triplet states in the two complexes are in good agreement with the experimental absorption and phosphorescence spectra. In this study, it was found that [Ir III Cl(L)(tterpy)] 2+ emits an intense phosphorescence at room temperature. Since the lowest unoccupied molecular orbitals (LUMOs) of all [Ir III Cl(L)(tterpy)] 2+ complexes are composed of the π*‐system contribution of the tterpy ligand, the spectroscopic and electrochemical results are discussed comparatively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Type of Medium:
Online Resource
ISSN:
1434-1948
,
1099-0682
DOI:
10.1002/ejic.v2007:13
DOI:
10.1002/ejic.200600995
Language:
English
Publisher:
Wiley
Publication Date:
2007
detail.hit.zdb_id:
1475009-0
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