Shafikov, Marsel Z. and Kozhevnikov, Dmitry N. and Bodensteiner, Michael and Brandl, Fabian and Czerwieniec, Rafal (2016) Modulation of Intersystem Crossing Rate by Minor Ligand Modifications in Cyclometalated Platinum(II) Complexes. INORGANIC CHEMISTRY, 55 (15). pp. 7457-7466. ISSN 0020-1669, 1520-510X
Full text not available from this repository. (Request a copy)Abstract
Photophysical properties of four new platinum(II) complexes comprising extended ppy (Hppy = 2-phenylpyridine) and thpy (Hthpy = 2-(2'-thienyl)pyridine) cyclometalated ligands and acetylacetonate (acac) are reported. Substitution of the benzene ring of Pt-ppy complexes 1 and 2 with a more electron-rich thiophene of Pt-thpy complexes 3 and 4 leads to narrowing of the HOMO-LUMO gap and thus to a red shift of the lowest energy absorption band and phosphorescence band, as expected for low-energy excited states of the intraligand/metal-to-ligand charge transfer character. However, in addition to these conventional spectral shifts, another, at first unexpected, substitution effect occurs. Pt-thpy complexes 3 and 4 are dual emissive showing fluorescence about 6000 cm(-1) (similar to 0.7S eV) higher in energy relative to the phosphorescence band, while for Pt-ppy complexes 1 and 2 only phosphorescence is observed. For dual-emissive complexes 3 and 4, ISC rates k(ISC) are estimated to be in order of 10(9)-10(10) s(-1)) while k(ISC) of Pt-ppy complexes 1 and 2 is much faster amounting to 10(12) s(-1) or more. The relative intensities of the fluorescence and phosphorescence signals' of Pt-thpy complexes 3 and 4 depend on the excitation wavelength; Showing that hyper-intersystem crossing (HISC) in the complexes is observably significant.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | AGGREGATION-INDUCED EMISSION; LIGHT-EMITTING DEVICES; TRANSITION-METAL-COMPLEXES; DISCRETE ORGANOPLATINUM(II) METALLACYCLES; ORGANIC ELECTROLUMINESCENT DEVICES; IRIDIUM(III) COMPLEXES; EXCITED-STATES; DUAL EMISSION; HEAVY-ATOM; DIPLATINUM(II,II) COMPLEXES; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie Chemistry and Pharmacy > Central Analytical Services |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 05 Apr 2019 11:31 |
| Last Modified: | 05 Apr 2019 11:33 |
| URI: | https://pred.uni-regensburg.de/id/eprint/3550 |
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