Two-dimensional self-assembly and complementary base-pairing between amphiphile nucleotides on graphite.

2D supramolecular structures on HOPG by self-assembly of physisorbed amphiphile nucleotides have been successfully imaged by high resolution STM. The organization of the systems depends on the nature of nucleic bases. In the case of the thymidine derivative a head-to-tail self-assembly is observed, whereas the amphiphile adenosine affords head-to-head nanostructures. The co-adsorption of complementary A+T amphiphile molecules induces the formation of a third head-to-head 2D supramolecular structure stabilized via base pairing. Molecular modelling calculations including the graphite surface provide models for all the 2D supramolecular systems observed.