Multivalent hydrogen-bonded architectures directed by self-complementarity between [Cu(2,2'-biimidazole)] and malonate building blocks.

The synthesis and structural characterization of four novel supramolecular hydrogen-bonded arrangements based on self-assembly from molecular `[Cu(2,2'-biimidazole)]' modules and malonate anions are presented, namely, tetrakis(2,2'-biimidazole)di-μ-chlorido-dimalonatotricopper(II) pentahydrate, [Cu 3 (C 3 H 2 O 4 ) 2 Cl 2 (C 6 H 6 N 4 ) 4 ]·5H 2 O or [Cu(H 2 biim) 2 (μ-Cl)Cu 0.5 (mal)] 2 ·5H 2 O, aqua(2,2'-biimidazole)malonatocopper(II) dihydrate, [Cu(C 3 H 2 O 4 )(C 6 H 6 N 4 )(H 2 O)]·2H 2 O or [Cu(H 2 biim)(mal)(H 2 O)]·2H 2 O, bis[aquabis(2,2'-biimidazole)copper(II)] dimalonatodiperchloratocopper(II) 2.2-hydrate, [Cu(C 6 H 6 N 4 ) 2 (H 2 O)] 2 [Cu(C 3 H 2 O 4 )(ClO 4 ) 2 ]·2.2H 2 O or [Cu(H 2 biim) 2 (H 2 O)] 2 [Cu(mal) 2 (ClO 4 ) 2 ]·2.2H 2 O, and bis(2,2'-biimidazole)copper(II) bis[bis(2,2'-biimidazole)(2-carboxyacetato)malonatocopper(II)] tridecahydrate, [Cu(C 6 H 6 N 4 ) 2 ][Cu(C 3 H 2 O 4 )(C 3 H 3 O 4 )(C 6 H 6 N 4 ) 2 ]·13H 2 O or [Cu(H 2 biim) 2 ][Cu(H 2 biim) 2 (Hmal)(mal)] 2 ·13H 2 O. These assemblies are characterized by self-complementary donor-acceptor molecular interactions, demonstrating a recurrent and distinctive pattern of hydrogen-bonding preferences among the carboxylate, carboxylic acid and N-H groups of the coordinated 2,2'-biimidazole and malonate ligands. Additionally, coordination of the carboxylate group with the metallic centre helps sustain remarkable supramolecular assemblies, such as layers, helices, double helix columns or 3D channeled architectures, including mixed-metal complexes, into a single structure.