Stable mixed-valent radicals from platinum(II) complexes of a bis(dioxolene) ligand.
Three diplatinum(II) complexes [{PtL}2(μ-thea)] (H4thea = 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.
School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT (UK), Fax: (+44) 113-343-6565; Current address: Department of Chemistry and Biochemistry, University of Arizona, P.O. Box 210041, 1306 East University Blvd., Tucson, AZ 85721-0041 (USA).
Jonathan J
JJ
Loughrey
Stephen
S
Sproules
Eric J L
EJ
McInnes
Michaele J
MJ
Hardie
Malcolm A
MA
Halcrow
charge transfer; dioxolenes; mixed-valent compounds; platinum; radical ions