Shafikov, Marsel Z. and Hodgson, Craig and Gorski, Aleksander and Kowalczyk, Aleksandra and Gapinska, Magdalena and Kowalski, Konrad and Czerwieniec, Rafal and Kozhevnikov, Valery N. (2022) Benzannulation of a ditopic ligand to afford mononuclear and dinuclear Ir(III) complexes with intense phosphorescence: applications in singlet oxygen generation and bioimaging. JOURNAL OF MATERIALS CHEMISTRY C, 10 (5). pp. 1870-1877. ISSN 2050-7526, 2050-7534
Full text not available from this repository. (Request a copy)Abstract
Annulation of the additional aromatic pi-system to the ligand is an effective method of influencing the luminescence of metal complexes. In this contribution, we show the effect of benzannulation of a ditopic ligand on the photophysical properties of a dinuclear Ir(iii) complex and also utilize it to prepare its mono-nuclear analogue. The new dinuclear complex di-Ir in which the iridium centres are linked by benzo[1,2-d : 4,5-d']bisthiazole shows drastically improved efficiency of phosphorescence compared to the previously reported complex Ir-2 that has thiazolo[5,4-d]thiazole as the linking unit. The new mono-nuclear complex mono-Ir, utilizing the same ditopic ligand as di-Ir, allows tracking the effects of dinuclearity. In degassed dilute dichloromethane solution, the mononuclear complex mono-Ir displays yellow phosphorescence (lambda(em) = 552 nm) with a quantum yield of phi(PL) = 70% and decay time of tau = 7.85 mu s, which correspond to the radiative rate of k(r) = 0.89 x 10(5) s(-1). The dinuclear complex di-Ir displays slightly red-shifted phosphorescence (lambda(em) = 560 nm) with a quantum yield of phi(PL) = 85% and decay time of tau = 4.50 mu s corresponding to the radiative rate of k(r) = 1.90 x 10(5) s(-1), which is about two times higher compared to that of the mono-nuclear mono-Ir. The phosphorescence intensity of both complexes is highly sensitive to molecular oxygen, as in the air-equilibrated samples the decay times drop to values tau = 0.73 mu s and tau = 0.84 mu s for mono-Ir and di-Ir, respectively. Applied as singlet oxygen sensitizers, mono-Ir and di-Ir show very high efficiencies of 78% and 71%, respectively. Such characteristics mean the two complexes are promising materials for optical oxygen sensing and applications associated with singlet oxygen generation.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TRIPLET EMITTERS; IRIDIUM(III); ENERGIES; M11-L |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 08 Sep 2022 05:59 |
| Last Modified: | 08 Sep 2022 05:59 |
| URI: | https://pred.uni-regensburg.de/id/eprint/47507 |
Actions (login required)
 |
View Item |
