Optical response of the Cu2S2 diamond core in
(NGuaS)2Cl2 |
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| Authors: | Matthias Witte Benjamin Grimm‐Lebsanft Arne Goos Stephan Binder Michael Rübhausen Martin Bernard Adam Neuba Serge Gorelsky Uwe Gerstmann Gerald Henkel Wolf Gero Schmidt Sonja Herres‐Pawlis |
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| Affiliation: | 1. Lehrstuhl Für Bioanorganische Chemie, Fachgruppe Chemie, RWTH Aachen University, Aachen, Germany;2. Institut für Nanostruktur‐ und Festk?rperphysik and Center for Free Electron Laser Science, University of Hamburg, Hamburg, Germany;3. Lehrstuhl Für Anorganische Chemie, Universit?t Paderborn, Paderborn, Germany;4. Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, Canada;5. Lehrstuhl Für Theoretische Physik, Universit?t Paderborn, Paderborn, Germany |
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| Abstract: | Density functional theory (DFT) and time‐dependent DFT calculations are presented for the dicopper thiolate complex Cu2(NGuaS)2Cl2 NGuaS=2‐(1,1,3,3‐tetramethylguanidino) benzenethiolate] with a special focus on the bonding mechanism of the Cu2S2Cl2 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 Cu2S2 diamond core mediated between Cu  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. |
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| Keywords: | DFT CuA site TD‐DFT copper thiolate complexes CDA |
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