The Coordination Behaviour of CuI Photosensitizers Bearing Multidentate Ligands Investigated by X-ray Absorption Spectroscopy |
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| Authors: | Martin Rentschler Sirma Iglesias Marie-Ann Schmid Dr Cunming Liu Dr Stefanie Tschierlei Dr Wolfgang Frey Dr Xiaoyi Zhang Dr Michael Karnahl Dr Dooshaye Moonshiram |
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| Institution: | 1. Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany;2. Instituto Madrileño de Estudios Avanzados en, Nanociencia (IMDEA Nanociencia), Calle Faraday, 9, 28049 Madrid, Spain;3. Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany;4. X-ray Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, IL, 60439 USA |
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| Abstract: | A systematic series of four novel homo- and heteroleptic CuI photosensitizers based on tetradentate 1,10-phenanthroline ligands of the type X^N^N^X containing two additional donor moieties in the 2,9-position (X=SMe or OMe) were designed. Their solid-state structures were assessed by X-ray diffraction. Cyclic voltammetry, UV-vis absorption, emission and X-ray absorption spectroscopy were then used to determine their electrochemical, photophysical and structural features in solution. Following, time-resolved X-ray absorption spectroscopy in the picosecond time scale, coupled with time-dependent density functional theory calculations, provided in-depth information on the excited state electron configurations. For the first time, a significant shortening of the Cu?X distance and a change in the coordination mode to a pentacoordinated geometry is shown in the excited states of the two homoleptic complexes. These findings are important with respect to a precise understanding of the excited state structures and a further stabilization of this type of photosensitizers. |
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| Keywords: | copper photosensitizers density functional calculations excited state structures multidentate ligands X-ray absorption spectroscopy |
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