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Stable Mixed‐Valent Radicals from Platinum(II) Complexes of a Bis(dioxolene) Ligand
Author(s) -
Loughrey Jonathan J.,
Sproules Stephen,
McInnes Eric J. L.,
Hardie Michaele J.,
Halcrow Malcolm A.
Publication year - 2014
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.201304848
Subject(s) - chemistry , radical , electron paramagnetic resonance , ligand (biochemistry) , platinum , methylene , crystallography , crystal structure , medicinal chemistry , stereochemistry , photochemistry , organic chemistry , catalysis , nuclear magnetic resonance , biochemistry , physics , receptor
Three diplatinum(II) complexes [{PtL} 2 (μ‐thea)] (H 4 thea=2,3,6,7‐tetrahydroxy‐9,10‐dimethyl‐9,10‐dihydro‐9,10‐ethanoanthracene) have been prepared, with diphosphine or bipyridyl “L” co‐ligands. One‐electron oxidation of these complexes gave radical cations containing a mixed‐valent [thea .] 3− ligand with discrete catecholate and semiquinonate centers separated by quaternary methylene spacers. The electronic character of these radicals is near the Robin–Day class II/III border determined by UV/Vis/NIR and EPR spectroscopies. Crystal‐structure determinations and a DFT calculation imply that oxidation of the thea 4− ligand may lead to an increased through‐space interaction between the dioxolene π systems.