The self-organisation of organic molecules into non-covalently bonded nanostructures, giving structures with a high degree of order, is an area of intense research activity as it has Potential applications in electronic and optical devices, in corrosion inhibition, and in supramolecular chemistry.

Jan Reedijk and colleagues in Leiden University have recently reported a rare, extended two-dimensional structure of hydrogen-bonded nucleic acid bases mediated by formate ions. While base-pairing is a well-known phenomenon, occurring in pairs, triplets and quadruplets as well as in larger structures, flat 2D structures are less common. This is even more true for protonated nuclobases.

The group of Bernhard Lippert at Dortmund University published a structure containing protonated adenine and neutral guanine in which base tetrads were H-bonded via the same sites and formed flat ribbons (but not an extended 2D-structure as in the present case). Lippert thinks that the unique shape and H-bonding properties of the formate ion explain the formation of an extended 2D structure in the case of the Leiden work.

The structure described by the Reedijk is not the only possible example of 2D nucleobase packing that can be imagined. Current work in the Leiden group is focusing on such systems, changing both the nucleic acid bases and the counter ions. 

Reedijk sees the challenge in this field as being the theory and modelling of such systems. From a theoretical point of view, this type of structure might have some bearing on the emergence of life. For Lippert, 'This finding may be of interest with regard to ongoing research of using nucleic acid constituents for surface patterning purposes, among others.'