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Photophysical behaviour of cyclometalated iridium(III) complexes with phosphino(terthiophene) ligands

TitlePhotophysical behaviour of cyclometalated iridium(III) complexes with phosphino(terthiophene) ligands
Publication TypeJournal Article
Year of Publication2013
AuthorsMoore, SA, Davies, DL, Karim, MM, Nagle, JK, Wolf, MO, Patrick, BO
JournalDALTON TRANSACTIONS
Volume42
Pagination12354-12363
ISSN1477-9226
Abstract

Six new Ir-III complexes containing the 3'-phosphino-2,2':5',2 `'-terthiophene (PT3) ligand in three different coordination modes are reported. The electronic properties of the complexes are characterized by cyclic voltammetry, absorption, emission and time-resolved transient absorption spectroscopies and DFT/TDDFT calculations. The electrochemical and photophysical behaviour of the complexes was found to be dominated by the PT3 ligand. For the complexes in which the PT3 ligand is coordinated in a bidentate P,S or P,C mode, the lowest energy absorption band is attributed to pi-pi{*} PT3 localized transitions consistent with observations from DFT calculations. Emission quantum yields are low in all cases (<0.07) and emission lifetimes are short (<50 ns). Intersystem crossing leads to a long-lived triplet state (L-3) also localized on the PT3 group. In the complex where the PT3 ligand is coordinated only via the phosphine, TDDFT calculations suggest that there is some MLCT (and Cl-PT3 CT) character in the lowest energy transition.

DOI10.1039/c3dt51320c