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Chromium Complexes with Oxido and Corrolato Ligands: Metal‐Based Redox Processes versus Ligand Non‐Innocence
Author(s) -
Garai Antara,
Sobottka Sebastian,
Schepper Rahel,
Sinha Woormileela,
Bauer Matthias,
Sarkar Biprajit,
Kar Sanjib
Publication year - 2018
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.201801452
Subject(s) - redox , chromium , ligand (biochemistry) , extended x ray absorption fine structure , non innocent ligand , chemistry , xanes , metal , electron paramagnetic resonance , electrochemistry , oxidation state , crystallography , inorganic chemistry , photochemistry , absorption spectroscopy , spectroscopy , organic chemistry , nuclear magnetic resonance , biochemistry , receptor , physics , electrode , quantum mechanics
Metal‐ versus ligand‐centered redox processes and the effects of substituents on the ligands on the spectroscopic properties of the metal complexes are at the heart of research on metal complexes with non‐innocent ligands. This work presents three examples of chromium complexes that contain both oxido and corrolato ligands, with the substituents on the corrolato ligands being different in the three cases. Combined X‐ray crystallographic, electrochemical, UV/Vis/NIR/EPR spectroelectrochemical, and EXAFS/XANES measurements, together with DFT calculations, have been used to probe the complexes in three different redox forms. This combined approach makes it possible to address questions related to chromium‐ versus corrolato‐centered redox processes, and the accessibility (or not) of Cr IV , Cr V , and Cr VI in these complexes, as well as their spin states. To the best of our knowledge, these are the first EXAFS/XANES investigations on Cr‐corrolato complexes in different redox forms, and hence these data should set benchmarks for future investigations on such complexes by this method.