Multiple Hydrogen Bonds in the Self-Assembly of Aminotriazine and Glutarimide. Decisive Role of the Triazine Substituents

The self-assembly of 6-R-2,4-diamino-1,3,5-triazines (R = phenyl, p-tolyl, piperidino) and glutarimide has given rise to three new complexes. The triazine:glutarimide ratio depends on the R group (1:1 for phenyl, 5, and p-tolyl, 6, and 2:1 for piperidino, 7). In all cases, a triple hydrogen bond between the triazine and the imide is formed but the 3D structure is clearly different depending on R group. In complexes 5 and 6, the triazine/glutarimide pairs interact through double hydrogen bonds of the type N−H···O/O···H−N to form dimers. In the case of 5, each dimer interacts with another four situated in a different plane and a zigzag sheet is formed. In 6, however, the dimers are almost parallel and planar sheets are thus obtained. In the case of 7, zigzag sheets are also formed but these consist of triazine/glutarimide units bonded to triazine molecules. Weak interactions (weak hydrogen bonds, C−H···π contacts and hydrophobic contacts) on or between sheets are observed. Common trends concerning the 3D structures have been found in these derivatives as well as for other previously described examples. Restricted rotation around the C−NH2 bond is observed at low temperature in solution.