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

摘要

The X-ray crystal structures of 1 [2[AMPYH] centre dot [(Cu (H_2O) (mal)_2)]:2H_2O] and 2 [2[AMPYH] centre dot [ZnBr (Hmal) (mal)]:2H_2O ] [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 R_2~2 (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 R_2~2(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.