The interplay of hydrogen-bonding and metal-coordination motifs in the formation of supramolecular patterns: Copper/zinc malonates–aminopyrimidine complexes

The X-ray crystal structures of 1 [2[AMPYH] · [(Cu (H2O) (mal)2)]:2H2O] and 2 [2[AMPYH] · [ZnBr (Hmal) (mal)]:2H2O ] [mal = malonate; Hmal = hydrogen malonate; AMPYH = 2-amino-4, 6-dimethylpyrimidinium] reveal the interplay of metal-coordination motifs and the hydrogen-bonding patterns . In both the structures, the 2-amino-4,6-dimethylpyrimidine cations are not directly coordinated to copper and zinc, but are hydrogen-bonded to the malonate ion. The protonated endocyclic nitrogen and the amino group of 2-amino-4,6-dimethylpyrimidine molecule interact with malonate ligand via a pair of N–H⋯O hydrogen-bonds, (with graph set notation R22(8)) whereas the unprotonated endocyclic nitrogen and the amino group interact with the malonate ligand via N–H..O and C–H⋯N hydrogen-bonds forming the same R22(8) motif. The combination of hydrogen-bonding motif and metal-coordination motif creates a novel supramolecular motif. The interplay of the hydrogen-bonding motif and metal-coordination motif via hydrogen-bonds leads to similar supramolecular motifs in both the structures.

Graphical abstractThe X-ray crystal structures of 1 [2[AMPYH] · [(Cu (H2O) (mal)2)]:2H2O] and 2 [2[AMPYH] · [ZnBr (Hmal) (mal)]:2H2O ] [mal = malonate; Hmal = hydrogen malonate; AMPYH = 2-amino-4,6-dimethylpyrimidinium] reveal the interplay of metal-coordination motifs and the hydrogen-bonding patterns. In both the structures, the 2-amino-4,6-dimethylpyrimidine cations are not directly coordinated to copper and zinc, but are hydrogen-bonded to the malonate ion. The protonated endocyclic nitrogen and the amino group of 2-amino-4,6-dimethylpyrimidine molecule interact with malonate ligand via a pair of N–H⋯O hydrogen-bonds, (with graph set notation R22(8)) whereas the unprotonated endocyclic nitrogen and the amino group interact with the malonate ligand via N–H..O and C–H⋯N hydrogen-bonds forming the same R22(8) motif. The combination of hydrogen-bonding motif and metal-coordination motif creates a novel supramolecular motif. The interplay of the hydrogen-bonding motif and metal-coordination motif via hydrogen bonds leads to similar supramolecular motifs in both the structures.Figure optionsDownload full-size imageDownload as PowerPoint slide