Electron transfer properties of non-alternant, substituted compounds related to fluoranthene. Experimental determination and theoretical modeling of electrochemical oxidation and reduction potentials in non-aqueous solution

The oxidation and reduction potentials of a series of related even non-alternant derivatives of 7,14-disubstituted acenaphth[1,2-k] fluoranthenes, and also fluoranthene, 7,10-diphenylfluoranthene and 8,9-dihydrodiindeno[1,2-j;2′,1′-] fluoranthene, were determined in organic solvents by cyclic voltammetry. The effects of steric hindrance on conjugation of the substituents with the central polycyclic aromatic hydrocarbon nucleus were evaluated. The semi-empirical molecular orbital calculation programs OMEGAMO, Extended Huckel, AM1 and PM3 were used to obtain optimal geometries and calculated HOMO and LUMO energies. As a further refinement, COSMO solvation was included in the AM1 calculations. The redox properties were correlated with data derived from the various semi-empirical calculations and the quality of these correlations is discussed. Inclusion of solvation energies in the computed molecular orbital energies results in a significant improvement in the correlation between observed and calculated oxidation potentials. © 1997 John Wiley & Sons, Ltd.