The Dihydropyrimidine-2,4-(1H,3H)-dione Functionality: a Suitable Module for Novel Crown-containing Hydrogen-bonded Supramolecular Assemblies

Two novel pyrimidine derivatives, 2-(2-methylphenyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine-5,7(4H,6H)-dione 3-oxide (H-PD) and 6-amino-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-ylsulfamic acid (H-PS), were synthesized and investigated as suitable ligands for co-crystallization with 1,10-diaza-18-crown-6 (DA18C6). Two solid compounds formulated as [(H

2

DA18C6)(PD)

2

(H

2

O)

4

] (1) and [(H

2

DA18C6)(PS)

2

(H

2

O)

2

] (2) have been shown by single-crystal structural analysis to be 2D and 3D networks, respectively, through extensive H-bonding intermolecular interactions. Both 1 and 2 incorporate the diaza-18-crown-6 units in the form of macrocyclic cations. In 1 the (PD)

-

anions deprotonated in the fourth position of the pyrimidine ring and water molecules are combined into 2D anionic sheets, the macrocyclic cations occupying the cavities in these sheets. In 2 the ensemble of donor and acceptor binding sites available in the 6-amino-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-ylsulfamate anions (PS)

-

facilitates their self-assembly into a double layer via diverse hydrogen bonds. Water molecules and H

2

-1,10-diazonia-18-crown-6 cations bridge the neighboring layers thus providing the final 3D supramolecular architecture.