An investigation of the three oxidation forms of lumiflavin

Abstract

Ab initio calculations with the 3–21 G basis set have been performed on the three oxidation forms of lumiflavin, and semiempirical MINDO/3 calculations have also been performed on these systems. The molecular geometries have been obtained and are in good agreement with available experimental data. The electronic distributions for the three oxidation forms have been studied, their differences providing some insight into the main chemical changes that occur to lumiflavin when involved in electron-transfer processes. The spin distribution for the radical form has also been calculated and compared to EPR results. Finally, calculations on the 2+ and 2– charged species for the oxidized and reduced forms have been performed to gain some novel insights into the possible aromatic character of these two compounds.