Computational and electrochemical studies on the redox reaction of for quinoxalin-2 ( H )-one and its derivatives in aqueous solution

The Quinoxalin-2(H)-one (QO) and its derivatives of 3-methylquinoxalin-2(1H)-one (MQO) and 3aminoquinoxalin-2(1H)-one (AQO) electrode potential s were calculated in aqueous phase. For this purpos e, the DFT/B3LYP method, with the 6-311G basis set was uti lized. The calculated value of the redox potentials re ative to SHE were 0.123 eV, 0.015 eV and -0.254 eV for QO, M QO and AQO respectively. The amino derivative is (0.76 eV) negative reduction potential because of amino g roup is more electron donating group comparison of methyl group. Energies of the highest occupied molecular o rbital (HOMO) and the energy of the lowest unoccupi ed molecular orbital (LUMO) of the studied compounds w ere calculated in gas phase and water. Both electro n d nor and electron acceptor substituents are effective in r ducing the energy gap between HOMO and LUMO. In addition, chemical potential (μ), chemical hardness ( η), global electrophilicity ( ω) and dipole moments were calculated. From the results shows that, quinoxalin-2-one, the gr ater is the tendency of the oxidized form to get reduced by accepting electrons and the amino derivative of qui noxalin-2-one is, the greater is the tendency of th e reduced form to get oxidized by donating electrons.