Y. W. Cao, X. D. Chai, T. J. Li, Jim Smith and DeQuan Li
Barbituric acid and melamine derivatives self-assembled into highly ordered structures from the molecular scale (≡3 Å) to geometric patterns on a macroscale (≡0.5 mm).
O absorption bands at 1754 (sh), 1740 (sh), 1724 (s), 1692 and 1668 cm–1. The stretching bands for amino groups in 1 are observed at 3450 (m), 3342 (m), 3271 (m) and 3164 (m) cm–1, and the N–H deformation bands appear at 1671 (sh) and 1627 (sh) cm–1. Upon self-assembly, the N–H vibrations become weak and shift to 3329–3259 (br) and 3138–3126 cm–1; the carbonyl vibrations change to new positions at 1733 (sh), 1705 (s) and 1675 (s) cm–1..