Electron-Transfer Processes in Indium(II) Iodide-o-Quinone Systems.
Indium(II) iodide reacts with various substituted o-quinones in nonaqueous solution by successive one-electron-transfer reactions to give (SQ)InI(2) products (SQ = semiquinonate radical anion). Electron spin resonance spectroscopy demonstrates the presence of both mono- and diradical species in the reaction mixture. Addition of 4-picoline to a mixture of In(2)I(4) and TBQ (=3,5-di-tert-butyl-o-quinone) in toluene causes the precipitation of the indium(III)-semiquinonate complex (TBSQ)InI(2)(pic)(2) whose structure has been established by X-ray crystallography: space group P&onemacr;, with a = 13.013(3) Å, b = 13.317(3) Å, c = 10.828(5) Å, alpha = 97.71(3) degrees, beta = 107.98(3) degrees, gamma = 103.92(3) degrees, V = 1684.8(1.2) Å(3), Z = 2. Refinement converged at R = 0.051 and R(w) = 0.064 for 5918 reflections at 23 degrees C. The InO(2)N(2)I(2) kernel is pseudooctahedral, and the structure confirms the presence of the semiquinonate ligand. A reaction scheme which incorporates these results is proposed.
Brown
Martyn A.
MA
Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
McGarvey
Bruce R.
BR
Ozarowski
Andrzej
A
Tuck
Dennis G.
DG