Imidazo-Phenanthroline Ligands as a Convenient Modular Platform for the Preparation of Heteroleptic Cu(I) Photosensitizers
by
Marie-Ann Schmid 1,†, Martin Rentschler 2,†, Wolfgang Frey 2, Stefanie Tschierlei 1,*
and Michael Karnahl 2,*
Marie-Ann Schmid 1,†, Martin Rentschler 2,†, Wolfgang Frey 2, Stefanie Tschierlei 1,* and Michael Karnahl 2,*
1
Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
2
Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Inorganics 2018, 6(4), 134; https://doi.org/10.3390/inorganics6040134
Received: 20 November 2018 / Revised: 5 December 2018 / Accepted: 10 December 2018 / Published: 12 December 2018
(This article belongs to the Special Issue First-Row Transition Metal Complexes)
The capture and storage of solar energy is a promising option to overcome current energy issues. To put such systems into practice, molecular photosensitizers should be based on abundant metals and possess a strong absorption capability for visible light. Therefore, a systematic series of four novel heteroleptic Cu(I) complexes of the type [(P^P)Cu(N^N)]+ (with P^P = xantphos and N^N = different diimine ligands) has been prepared. As an essential feature, these copper photosensitizers contain an imidazole moiety at the backbone of the diimine ligand, which increases the aromatic π-system compared to phenanthroline type ligands. Moreover, 2-(4-bromophenyl)-1-phenyl-1H-imidazo-[4,5-f][1,10]phenanthroline was used as a starting point and modular platform for gradually extended diimine ligands. Suzuki cross-coupling was applied to introduce different kind of substituents in the back of this ligand. Afterwards, a combination of NMR spectroscopy, mass spectrometry, X-ray analysis, cyclic voltammetry, UV/vis and emission spectroscopy was used to investigate the structural, electrochemical and photophysical properties of these compounds. As a result, a reversible reduction, strongly increased extinction coefficients and significantly redshifted absorption maxima (>20 nm) were found compared to traditional Cu(I) photosensitizers without an imidazo moiety. Moreover, these compounds show a bright emission in the solid state.
View Full-Text
Keywords:
copper photosensitizers; imidazo-phenanthroline ligands; Suzuki coupling; X-ray analysis; photophysics; structure-property relationships
▼
Show Figures
Graphical abstract
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
- Supplementary File 1:
ZIP-Document (ZIP, 3198 KB)
MDPI and ACS Style
Schmid, M.-A.; Rentschler, M.; Frey, W.; Tschierlei, S.; Karnahl, M. Imidazo-Phenanthroline Ligands as a Convenient Modular Platform for the Preparation of Heteroleptic Cu(I) Photosensitizers. Inorganics 2018, 6, 134.
Show more citation formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.
Search more from Scilit
