title: Optical response of the Cu2 S2 diamond core in Cu2II(NGuaS)2 Cl2.
abstract: Density functional theory (DFT) and time-dependent DFT calculations are presented for the dicopper thiolate complex Cu2 (NGuaS)2 Cl2 [NGuaS=2-(1,1,3,3-tetramethylguanidino) benzenethiolate] with a special focus on the bonding mechanism of the Cu2 S2 Cl2 core and the spectroscopic response. This complex is relevant for the understanding of dicopper redox centers, for example, the CuA center. Its UV/Vis absorption is theoretically studied and found to be similar to other structural CuA models. The spectrum can be roughly divided in the known regions of metal d-d absorptions and metal to ligand charge transfer regions. Nevertheless the chloride ions play an important role as electron donors, with the thiolate groups as electron acceptors. The bonding mechanism is dissected by means of charge decomposition analysis which reveals the large covalency of the Cu2 S2 diamond core mediated between Cu dz2 and S-S π and π* orbitals forming Cu-S σ bonds. Measured resonant Raman spectra are shown for 360- and 720-nm excitation wavelength and interpreted using the calculated vibrational eigenmodes and frequencies. The calculations help to rationalize the varying resonant behavior at different optical excitations. Especially the phenylene rings are only resonant for 720 nm. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Lehrstuhl Für Bioanorganische Chemie, Fachgruppe Chemie, RWTH Aachen University, Landoltweg 1, Aachen, 52074, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Witte
authors.affiliation: Institut für Nanostruktur- und Festkörperphysik and Center for Free Electron Laser Science, University of Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Grimm-Lebsanft
authors.affiliation: Institut für Nanostruktur- und Festkörperphysik and Center for Free Electron Laser Science, University of Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany.
authors.forename: Arne
authors.initials: A
authors.lastname: Goos
authors.affiliation: Institut für Nanostruktur- und Festkörperphysik and Center for Free Electron Laser Science, University of Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Binder
authors.affiliation: Institut für Nanostruktur- und Festkörperphysik and Center for Free Electron Laser Science, University of Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Rübhausen
authors.affiliation: Lehrstuhl Für Anorganische Chemie, Universität Paderborn, Warburger Str. 100, Paderborn, 33098, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Bernard
authors.affiliation: Lehrstuhl Für Anorganische Chemie, Universität Paderborn, Warburger Str. 100, Paderborn, 33098, Germany.
authors.forename: Adam
authors.initials: A
authors.lastname: Neuba
authors.affiliation: Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
authors.forename: Serge
authors.initials: S
authors.lastname: Gorelsky
authors.affiliation: Lehrstuhl Für Theoretische Physik, Universität Paderborn, Warburger Str. 100, Paderborn, 33098, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Gerstmann
authors.affiliation: Lehrstuhl Für Anorganische Chemie, Universität Paderborn, Warburger Str. 100, Paderborn, 33098, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Henkel
authors.affiliation: Lehrstuhl Für Theoretische Physik, Universität Paderborn, Warburger Str. 100, Paderborn, 33098, Germany.
authors.forename: Wolf
authors.initials: W
authors.lastname: Gero Schmidt
authors.affiliation: Lehrstuhl Für Bioanorganische Chemie, Fachgruppe Chemie, RWTH Aachen University, Landoltweg 1, Aachen, 52074, Germany.
authors.forename: Sonja
authors.identifier: 0000-0002-4354-4353
authors.initials: S
authors.lastname: Herres-Pawlis
keywords: CDA; CuA site; DFT; TD-DFT; copper thiolate complexes