Experimental and first-principles study of guanine adsorption on ZnO clusters

Theoretical investigation of guanine, DNA base adsorption on the ZnO model clusters, viz. , Zn 2 O 2 , Zn 3 O 3 , Zn 4 O 4 ring (R) and Zn 4 O 4 wurtzite (W) in terms of geometry, binding site, binding energy ( E B ), energy gap ( E g ), electronic and spectral properties were studied by a density f...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2014-11, Vol.16 (42), p.23461-23475
Main Authors: Chandraboss, V. L, Karthikeyan, B, Senthilvelan, S
Format: Article
Language:English
Subjects:
Adsorption
Binding energy
Clusters
Electronics
Energy gap
Guanine - chemistry
Guanines
Quantum Theory
Spectroscopy
Surface Properties
Zinc oxide
Zinc Oxide - chemistry
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Summary:Theoretical investigation of guanine, DNA base adsorption on the ZnO model clusters, viz. , Zn 2 O 2 , Zn 3 O 3 , Zn 4 O 4 ring (R) and Zn 4 O 4 wurtzite (W) in terms of geometry, binding site, binding energy ( E B ), energy gap ( E g ), electronic and spectral properties were studied by a density functional theory (DFT) method. The guanine adsorption on the ZnO (G-ZnO) clusters is modeled by the B3LYP/LanL2DZ method. The calculated binding energy ( E B ) and energy gap ( E g ) of the guanine molecule are highly dependent on the nature of the cluster size and vary with the size of the clusters. Physisorption proceeded via formation of the N Zn bond between guanine and the active Zn 2+ site on ZnO. The HOMO-LUMO energies show that charge transfer occurs in the G-ZnO clusters, from ZnO to guanine to better understand the interaction. The Mulliken charges are computed. The electronic properties of ZnO and G-ZnO clusters were compared with different basis sets (B3LYP/6-31G, B3LYP/6-311G, MP2/6-31G and MP2/LanL2DZ). Experimental information like microscopic and spectroscopic evidence is also included for understanding the guanine-ZnO interactions. The G-ZnO composite was prepared by a precipitation method and characterized by SEM with EDX, FT-IR and FT-RAMAN analysis. The interaction of guanine with ZnO nanoparticles was observed by UV-vis spectroscopy. The experimental results are compared with the DFT results in the light of these new insights. Electronic structure for interaction of guanine with Zn 2 O 2 cluster and the most preferred N1-site to form a stable G-Zn 2 O 2 model.
ISSN:1463-9076
1463-9084
DOI:10.1039/c4cp03274h