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The Coordination Behaviour of Cu I Photosensitizers Bearing Multidentate Ligands Investigated by X‐ray Absorption Spectroscopy
Author(s) -
Rentschler Martin,
Iglesias Sirma,
Schmid MarieAnn,
Liu Cunming,
Tschierlei Stefanie,
Frey Wolfgang,
Zhang Xiaoyi,
Karnahl Michael,
Moonshiram Dooshaye
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201905601
Subject(s) - homoleptic , excited state , chemistry , spectroscopy , x ray absorption spectroscopy , crystallography , absorption spectroscopy , denticity , absorption (acoustics) , cyclic voltammetry , picosecond , density functional theory , photochemistry , electrochemistry , materials science , crystal structure , computational chemistry , metal , organic chemistry , laser , atomic physics , optics , electrode , physics , quantum mechanics , composite material
A systematic series of four novel homo‐ and heteroleptic Cu I 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.