Ground- And Excited-State Properties of Iron(II) Complexes Linked to Organic Chromophores
Reviewartikel, 2020

Two new bichromophoric complexes, [Fe(bim-ant)2]2+ and [Fe(bim-pyr)2]2+ ([H2-bim]2+ = 1,1′-(pyridine-2,6-diyl)bis(3-methyl-1H-imidazol-3-ium); ant = 9-anthracenyl; pyr = 1-pyrenyl), are investigated to explore the possibility of tuning the excited-state behavior in photoactive iron(II) complexes to design substitutes for noble-metal compounds. The ground-state properties of both complexes are characterized thoroughly by electrochemical methods and optical absorption spectroscopy, complemented by time-dependent density functional theory calculations. The excited states are investigated by static and time-resolved luminescence and femtosecond transient absorption spectroscopy. Both complexes exhibit room temperature luminescence, which originates from singlet states dominated by the chromophore (1Chrom). In the cationic pro-ligands and in the iron(II) complexes, the emission is shifted to red by up to 110 nm (5780 cm-1). This offers the possibility of tuning the organic chromophore emission by metal-ion coordination. The fluorescence lifetimes of the complexes are in the nanosecond range, while triplet metal-to-ligand charge-transfer (3MLCT) lifetimes are around 14 ps. An antenna effect as in ruthenium(II) polypyridine complexes connected to an organic chromophore is found in the form of an internal conversion within 3.4 ns from the 1Chrom to the 1MLCT states. Because no singlet oxygen forms from triplet oxygen in the presence of the iron(II) complexes and light, efficient intersystem crossing to the triplet state of the organic chromophore (3Chrom) is not promoted in the iron(II) complexes.

excited states

catechol derivative

charge transfer

Författare

Philipp Dierks

Universität Paderborn

Ayla Päpcke

Kazan Federal University

Universität Rostock

Olga S. Bokareva

Universität Rostock

Kazan Federal University

Björn Altenburger

Universität Rostock

Chalmers, Fysik, Kemisk fysik

Thomas Reuter

Johannes Gutenberg-Universität Mainz

Katja Heinze

Johannes Gutenberg-Universität Mainz

Oliver Kühn

Universität Rostock

Stefan Lochbrunner

Universität Rostock

Matthias Bauer

Universität Paderborn

Inorganic Chemistry

0020-1669 (ISSN) 1520-510X (eISSN)

Vol. In Press

Ämneskategorier

Oorganisk kemi

Atom- och molekylfysik och optik

Annan kemi

DOI

10.1021/acs.inorgchem.0c02039

PubMed

32935979

Mer information

Senast uppdaterat

2020-11-11