Fluorescent Bis(guanidine) Copper Complexes as Precursors for Hydroxylation Catalysis
Florian Strassl,
Alexander Hoffmann,
Benjamin Grimm-Lebsanft,
Dieter Rukser,
Florian Biebl,
Mai Anh Tran,
Fabian Metz,
Michael Rübhausen,
Sonja Herres-Pawlis
Affiliations
Florian Strassl
Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
Alexander Hoffmann
Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
Benjamin Grimm-Lebsanft
Institut für Nanostruktur- und Festkörperphysik, Universität Hamburg and Center For Free Electron Laser Science, Notkestrasse 85, 22607 Hamburg, Germany
Dieter Rukser
Institut für Nanostruktur- und Festkörperphysik, Universität Hamburg and Center For Free Electron Laser Science, Notkestrasse 85, 22607 Hamburg, Germany
Florian Biebl
Institut für Nanostruktur- und Festkörperphysik, Universität Hamburg and Center For Free Electron Laser Science, Notkestrasse 85, 22607 Hamburg, Germany
Mai Anh Tran
Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
Fabian Metz
Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
Michael Rübhausen
Institut für Nanostruktur- und Festkörperphysik, Universität Hamburg and Center For Free Electron Laser Science, Notkestrasse 85, 22607 Hamburg, Germany
Sonja Herres-Pawlis
Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
Bis(guanidine) copper complexes are known for their ability to activate dioxygen. Unfortunately, until now, no bis(guanidine) copper-dioxygen adduct has been able to transfer oxygen to substrates. Using an aromatic backbone, fluorescence properties can be added to the copper(I) complex which renders them useful for later reaction monitoring. The novel bis(guanidine) ligand DMEG2tol stabilizes copper(I) and copper(II) complexes (characterized by single crystal X-ray diffraction, IR spectroscopy, and mass spectrometry) and, after oxygen activation, bis(µ-oxido) dicopper(III) complexes which have been characterized by low-temperature UV/Vis and Raman spectroscopy. These bis(guanidine) stabilized bis(µ-oxido) complexes are able to mediate tyrosinase-like hydroxylation activity as first examples of bis(guanidine) stabilized complexes. The experimental study is accompanied by density functional theory calculations which highlight the special role of the different guanidine donors.
