Coexistence of homochiral and heterochiral adenine domains at the liquid/solid interface.

In this work, the self-assembly of the DNA base molecule adenine (A) is imaged with high-resolution scanning tunneling microscopy (STM) at the liquid (1-octanol)/solid (HOPG) interface at room temperature. Rather surprisingly, the STM results reveal, for the first time, the spontaneous formation of two coexisting distinct (homo- and heterochiral) domains of adenine, which are formed at the liquid/solid interface without changing any experimental conditions. Ab initio density functional theory (DFT) calculations support our STM findings and suggest the existence of various A networks of nearly similar stability that all are constructed from the most stable A dimer.