Computational study of the structure, ionization energy and electron affinity of 2,5-dihydroxy-1,4-benzoquinone and its derivatives

All possible conformers of 2,5-dihydroxy-1,4-benzoquinone (DHBQ) and its derivatives were thoroughly optimized at B3LYP/6-31G(2df,p) level of theory. Furthermore, to have more reliable energies in the case of the more stable conformers, their total energies were recomputed at the G4(MP2) level. For all studied species, when the orientation of all hydrogen of hydroxyl groups are towards carbonyl groups, strong intra-hydrogen bonds make the conformer more stable. The ionization energies (IE) and electron affinities (EA) of the species were also calculated. Computational results confirmed that derivatives with F, Cl and OH substituent as electron donor groups lose one electron easier than DHBQ. All calculated electron affinities showed that electron donor groups can increase the ability of DHBQ to accept π electron.