Universität zu Köln

Cao, Xiaoyan ORCID: 0000-0002-3438-575X and Dolg, Michael (2022). Ab initio studies on a highly luminescent and oxygen-sensitive Tb(III) complex with a 1,4,7-triazacyclononane-based tris-aryloxide ligand. J. Lumines., 252. AMSTERDAM: ELSEVIER. ISSN 1872-7883

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Abstract

The strongly luminescent and highly oxygen-sensitive Tb(III) complex [{((ArO)-Ar-MeMe)(3)tacn}Tb-III(THF)] (denoted hereafter as [1(Tb) THF]) was studied with density functional theory (DFT) and wavefunction-based ab initio electronic structure methods combined with Tb relativistic ab initio pseudopotentials. The optimized geometries as well as the calculated UV-vis absorption spectra at the DFT level agree well with the available experimental data. The calculated vertical S-0*/D-5(4) -> S-0*/F-7(J) (ligand/Tb3+ states) emission energies for J = 0-6 at the RSPT2//CASSCF level including spin-orbit corrections are 475, 511, 549, 583, 614, 638, and 644 nm, respectively, and are lower by 15, 36, 39, 39, 39, 35, and 35 nm, respectively, than the corresponding experimental values. The luminescence quenching mechanism of [1(Tb) THF] in presence of O-2 was investigated. RSPT2//CASSCF calculations for [1(Tb) THF]center dot O-2 indicate that the S-0*/F-7(J) (J = 0-6)/O-1(2) ((1)Delta(g) or (1)Sigma(+)(g)) states (ligand/Tb3+/O-2 states) are energetically more stable than the emission states S-0*/D-5(J) (J = 0-4)/O-3(2) ((3)Sigma(-)(g)). Therefore, after initial photo excitation of the ligand and subsequent energy transfer to the Tb3+ ion, the energy will be further transferred to O-2 leading to the observed luminescence quenching of [1(Tb) THF] in air. A comparison is made to [1(Sm) THF]center dot O-2 which shows a significantly smaller luminescence quantum yield and no oxygen quenching.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Cao, Xiaoyan UNSPECIFIED orcid.org/0000-0002-3438-575X UNSPECIFIED Dolg, Michael UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-660133
DOI:	10.1016/j.jlumin.2022.119421
Journal or Publication Title:	J. Lumines.
Volume:	252
Date:	2022
Publisher:	ELSEVIER
Place of Publication:	AMSTERDAM
ISSN:	1872-7883
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ELECTRONIC-ENERGY LEVELS; LANTHANIDE AQUO IONS; VALENCE BASIS-SETS; PSEUDOPOTENTIALS; APPROXIMATION Multiple languages Optics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/66013