Journal of the American Chemical Society, Vol.134, No.10, 4806-4811, 2012
HOMO Energy Gap Dependence of Hole-Transfer Kinetics in DNA
DNA consists of two type of base-pairs, G-C and A-T, in which the highest occupied molecular orbital (HOMO) localizes on the purine bases G and A. While the hole transfer through consecutive Gs or As occurs faster than 10(9) s(-1), a significant drop in the hole transfer rate was observed for G-C and A-T mixed random sequences. In this study, by using various natural and artificial nucleobases having different HOMO levels, the effect of the HOMO-energy gap between bases (Delta(HOMO)) on the hole-transfer kinetics in DNA was investigated. The results demonstrated that the hole transfer rate can be increased by decreasing the A(HOMO) and can be finely tuned over 3 orders of magnitude by varying the Delta(HOMO).