75826-70-9Relevant articles and documents
Reduction-Oxidation Properties of Organotransition-metal Complexes. Part 19. Carbonylruthenium Catecholate and Semiquinone Complexes
Connelly, Neil G.,Manners, Ian,Protheroe, John R. C.,Whiteley, Mark W.
, p. 2713 - 2718 (2007/10/02)
Tetrachlorobenzene-o-quinone (o-chloranil) and (L' = η4-2,3-dimethylbuta-1,3-diene) give the catecholate-bridged dimer 2> (1) which undergoes bridge-cleavage reactions with Group 5 donors, L, and halide ions, X(1-), yielding the complexes and (1-) (3; X = Cl, Br, or I), respectively.Cyclic voltammetry at a platinum electrode shows that compounds (2) and (3) undergo two one-electron oxidations; chemical oxidation of (2), with AgPF6 or , and of (3), with , yields and (5; X = Cl, Br, or I), respectively.Complex (5; X = Br or I) may also be prepared directly from (1) and bromine or iodine.E.S.r. spectroscopy suggests that (4) and (5) are semiquinone complexes of ruthenium(II) and, therefore, that the oxidation of (2) and (3) is largely associated with the chelating ligand.However, the hyperfine coupling observed shows the unpaired electron density to be partially delocalised over the metal and axial ligands.
