Complexes of DNA bases and gold clusters Au3 and Au4 involving nonconventional N-H•••Au hydrogen bonding

DNA base-gold interactions are studied theoretically at the DFT level using Au-3 and Au-4 clusters as simple catalytic models for Au particles. The bonding between DNA bases and gold clusters occurs via the anchoring of a Au atom to the N or 0 atoms of the bases. In the most stable planar base-Au-3 complexes, the Au-N or Au-O anchor bonds are reinforced by N-H center dot center dot center dot Au bonds. The mechanism of formation of these nonconventional H-bonds is discussed.