Stable Mixed‐Valent Radicals from Platinum(II) Complexes of a Bis(dioxolene) Ligand

Abstract

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 thea4− ligand may lead to an increased through-space interaction between the dioxolene π systems.

Platinum(ii) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene

“… 9 , 30 , 46 That contrasts with the cat/sq radicals [{PtL} 2 (thea˙)] + (L = dppb or dppe; Scheme 1 ) which exhibit narrower IVCT bands that are more characteristic of the class III formalism. 15 …”

Rigidification of a macrocyclic tris-catecholate scaffold leads to electronic localisation of its mixed valent redox product

“…, generated by in situ oxidation of the neutral precursors with 1 equiv [Cp 2 Fe]PF 6 , were measured in frozen CH 2 Cl 2 solution at X-and S-band frequencies. The spectra resemble [1a • ] + and other Pt(II)/sq radicals in showing weakly rhombic g-patterns, with hyperfine coupling to just one 195 Pt nucleus (ESI †) 14,21,22. That shows the unpaired electrons in [2a…”

Indirect Magnetic Exchange between o-Iminosemiquinonate Ligands Controlled by Apical Substituent in Pentacoordinated Gallium(III) Complexes

“…Anal. Preparation of imSQ 2 GaN 3 (3). The solution of imSQ 2 GaI (6) (0.5 g, 0.528 mmol) in THF (25 mL) was added to 0.34 g of sodium azide (5.28 mmol).…”