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The two centrosymmetric dinuclear copper paddle-wheel complexes tetrakis(μ-4-hydroxybenzoato-κ2 O: O′)bis[aquacopper(II)] dimethylformamide disolvate dihydrate, [Cu2(C7H5O3)4(H2O)2]·2C3H7NO·2H2O, (I), and tetrakis(μ-4-methoxybenzoato-κ2 O: O′)bis[(dimethylformamide-κ O)copper(II)], [Cu2(C8H7O3)4(C3H7NO)2], (II), crystallize with half of the dinuclear paddle-wheel cage unit in the asymmetric unit and, in addition, complex (I) has one dimethylformamide (DMF) and one water solvent molecule in the asymmetric unit. In both (I) and (II), two CuII ions are bridged by four syn, syn-η1:η1:μ carboxylate groups, showing a paddle-wheel cage-type structure with a square-pyramidal coordination geometry. The equatorial positions of (I) and (II) are occupied by the carboxylate groups of 4-hydroxy- and 4-methoxybenzoate ligands, and the axial positions are occupied by aqua and DMF ligands, respectively. The three-dimensional supramolecular metal-organic framework of (I) consists of three different R22(20) and an R44(36) ring motif formed via O-H...O and O W-H W...O hydrogen bonds. Complex (II) simply packs as molecular species. [ABSTRACT FROM AUTHOR]

Polymorphs of 2-amino-4,6-dimethoxypyrimidine [ADMP (1)], 2,4-diamino-6-methyl-1,3,5-triazine [DAMT ( 2 )], 2,4-diamino-6-phenyl-1,3,5-triazine [DAPT ( 3 )] and a solvate of DAPT with DMF solvent, [DAPT·DMF ( 4 )] were obtained either during a systematic screening using various solvents or by serendipity. These polymorphs and solvates were then characterized using single crystal X-ray diffraction technique and their structural and supramolecular aspects are analyzed. The supramolecular architecture of compounds ( 1 – 4 ) are predominantly hydrogen bonded via N–H⋯N base pairs. These base pairs are formed either between crystallographically independent molecules in the lattice or between symmetry related molecules. The molecular self assembly process involved in 2 , 3 and 4 , facilitates the formation of some base pair motifs with graph-set of R 2 2 (8) and a rare non-complementary base pair motif with graph-set R 2 2 (10). The other interesting supramolecular patterns and non-covalent interactions which lead to the formation of new forms are discussed in detail. [ABSTRACT FROM AUTHOR]