The guanine-cytosine base hybrid I is synthesized in five steps from the malononitrile dimer. One face of the molecule possesses the cytosine AAD hydrogen bonding code and the other the guanine DDA code. The expression of this information leads to the self-organization of six molecules of I into a hexagonal supermacrocycle in the solid state through the formation of 18 strong hydrogen bonds. This is the first structurally characterized example of a synthetic hexagonal assembly where the molecular program is unambiguous and all of the information required for exclusive rosette formation is contained within hydrogen bonding codes. 1 crystallizes in the very rare, high-symmetry cubic space group Ia3d, with 96 molecules in the unit cell. The crystal is highly solvated and only ca. 35% occupied by molecules of 1, with a criss-crossed network of channel voids generated by the overlapping of 16 hexamers.
ASJC Scopus subject areas
- Organic Chemistry