Evidence for strong mixing between the LC and MLCT excited states in Bis(2-phenylpyridinato-C[sup 2], N')(2, 2'-bipyridine)iridium(III)

Journal Article · Wed Jul 07 00:00:00 EDT 1993 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00066a020· OSTI ID:5785181

Colombo, M G; Hauser, A; Guedel, H U ^[1]

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1. Universitaet Bern (Switzerland)

The well-resolved absorption, excitation, and luminescence spectra of [Ir(ppy)[sub 2]bpy][sup +] (ppyH = 2-phenylpyridine, bpy = 2, 2'-bipyridine) in different media at cryogenic temperatures are presented. In solutions and glasses at ambient temperature the lowest energy excited state corresponds to an Ir [yields] bpy charge-transfer excitation whereas in the crystalline host lattice [Rh(ppy)[sub 2]bpy]PF[sub 6] the lowest excited state at 21,450 cm[sup [minus]1] is assigned to a [sup 3][pi]-[pi]* excitation localized on the cyclometalating ppy[minus] ligands. The next higher excited Ir [yields] bpy charge-transfer state has shifted to 21,820 cm[sup [minus]1], only 300 cm[sup [minus]1] above the [sup 3]LC excited state. The close proximity of the [sup 3]LC and [sup 3]MLCT excited states and the large spin-orbit coupling constant of Ir[sup 3+] induce a strong mixing of charge-transfer character into the [sup 3]LC lowest excited states, resulting in increased oscillator strengths, reduced lifetimes, short axis polarized transitions, and a large zero-field splitting of 10-15 cm[sup [minus]1].

• OSTI ID: 5785181
• Journal Information: Inorganic Chemistry; (United States), Vol. 32:14; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
IRIDIUM COMPLEXES
EXCITED STATES
ABSORPTION SPECTROSCOPY
BIPYRIDINES
ELECTRONIC STRUCTURE
L-S COUPLING
LIFETIME
LUMINESCENCE
MATHEMATICAL MODELS
OSCILLATOR STRENGTHS
AZINES
COMPLEXES
COUPLING
ENERGY LEVELS
HETEROCYCLIC COMPOUNDS
INTERMEDIATE COUPLING
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties