Hydrogen-bonding tectons for the construction of bimolecular framework materials

Three hydrogen-bonding tectons functionalised with pyrimidine-dione hydrogen-bonding moieties, either uracil or thymine groups, have been synthesised and their solid-state structures studied by single crystal X-ray diffraction. The tectons have different linkers between the pyrimidine-dione hydrogen-bonding groups. Whereas tectons 1 and 2 have either naphthalenetetracarboxylic diimide or p-xylyl spacers, respectively, linking two hydrogen-bonding appendages, tecton 3 comprises three thymine moieties linked via a 2,4,6-tris(methyl)mesitylene spacer. All three tectons have been structurally characterised and in the case of 2 and 3 exhibit the anticipated R²₂(8) double hydrogen-bonded arrangement between the imide moieties. In contrast, the single crystal structure of the DMSO solvate of 1 does not exhibit inter-tecton hydrogen-bonding but adopts N–HO interactions with guest DMSO molecules. However, bimolecular hydrogen-bonded adducts have successfully been prepared exploiting the complementary triple hydrogen-bonding interactions between 1, or 2, and melamine to give two-dimensional hydrogen-bonded sheets.