title: Effects of bioconjugation on the structures and electronic spectra of CdSe: density functional theory study of CdSe-adenine complexes.
abstract: We present density functional theory (DFT) and time-dependent DFT (TD-DFT) study of the structures and electronic spectra of small CdSe nanocluster-adenine complexes Cd(n)Se(n)-adenine (n = 3, 6, 10, 13). We examine the changes in the geometries and excitation spectra of the nanoclusters induced by DNA base-binding. By comparing the results calculated for the bare (Cd(n)Se(n)), hydrogen-passivated (Cd(n)Se(n)H(2n)), as well as the corresponding adenine (Ade)-bound clusters (Cd(n)Se(n)-Ade, Cd(n)Se(n)H(2n)-Ade, Cd(n)Se(n)H(2n-2)-Ade), we find that binding with Ade slightly blue-shifts (up to 0.18 eV) the electronic excitations of bare nanoclusters but strongly red-shifts (<1.2 eV) those of hydrogen-passivated nanoclusters. Natural bond orbital analysis shows that the LUMO of Cd(n)Se(n)H(2n)-Ade is a pi* orbital located on the purine ring.
authors.affiliation: Department of Applied Chemistry, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Ho-Sung
authors.initials: HS
authors.lastname: Kim
authors.forename: Sung-Woo
authors.initials: SW
authors.lastname: Jang
authors.forename: Sang-Yoon
authors.initials: SY
authors.lastname: Chung
authors.forename: Sungyul
authors.initials: S
authors.lastname: Lee
authors.forename: Yonghoon
authors.initials: Y
authors.lastname: Lee
authors.forename: Bongsoo
authors.initials: B
authors.lastname: Kim
authors.forename: Christopher
authors.initials: C
authors.lastname: Liu
authors.forename: Daniel
authors.initials: D
authors.lastname: Neuhauser
mesh_terms: D000225:Adenine / Q000737:chemistry*; D019187:Cadmium Compounds / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D004583:Electrons; D053768:Metal Nanoparticles / Q000737:chemistry*; D008968:Molecular Conformation; D018036:Selenium Compounds / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D019187:Cadmium Compounds; D056831:Coordination Complexes; D018036:Selenium Compounds; C058667:cadmium selenide; D000225:Adenine