Adsorption of Poly-Functional 5-Flourouracile and 2,4-Dithio-5-Fluorouracil on Au(111)Surface: Structure, Energy and Electronic Property

We have studied the adsorption of 5-Flourouracile (5-FU) and 2,4-Dithio-5-Flourouracile (2,4-DT-5-FU) on Au(111) surface at low coverage using periodic-slab-DFT calculation. Isolated 5-FU molecule adsorbs preferentially at bridge site in a vertical configuration via NH group by forming the N–H…Au nonconventional H-bond. The Au-O anchor bond formation is not observed. Substitution of oxygen atoms in 5-FU with sulfur (2,4-DT-5-FU) influences the nature of adsorption strongly and leads to the anchoring Au–S bond and the N–H…Au nonconventional H-bond of single 2,4-DT-5FU molecule to gold surface. The adsorption site and orientation of 2,4-DT-5-FU molecule on the surface are similar to that of 5-FU. Comprehensive electronic structure information is obtained through wave function analysis for the stable optimized structures.

Keywords:

DFT , PDOS , Au(111) , 5-Flourouracile , 2 , 4-Dithio-5-Flourouracile