DNA Base–Gold Nanocluster Complex as a Potential Catalyzing Agent: An Attractive Route for CO Oxidation Process

The important contribution of DNA to modern day nanobiotechnology is sometimes ascribed to its potential role as a programmable building block for the assembly of nanomaterials. In this work, our density functional theory (DFT) based study explores the possibilities of using complexes of DNA bases (viz., adenine (A), thymine (T), guanine (G), and cytosine (C)) as well as DNA base pairs (such as A-T, C-G, and G4-quadruplex) with the gold cluster Au 3 as a model catalyst system for oxidation of CO to CO 2 . The complexes are energetically stable, and our calculated binding energies of the gold cluster–DNA base complexes are found to match closely with the experimentally obtained heat of desorption of DNA bases on Au films. Our results also reveal that the oxidation of CO on these complexes takes place exclusively via an Eley–Rideal (E-R) type of mechanism whereas both E-R and Langmuir–Hinshelwood (L-H) mechanisms for this reaction are observed for a bare Au 3 cluster. More interestingly, the CO oxidation reaction on the gold cluster (in the complexes) is found to be more facile, with a lesser activation barrier and higher heat of formation of the products, as compared to that of a pristine Au 3 cluster. Our results suggest that DNA base–gold cluster complexes can be an attractive and efficient catalytic model system that can have wider ramifications. Since the nanoscale gold is already known as a potential catalyst for variety of chemical reactions, our approach will richly supplement to the expanding horizons of catalysis involving gold.