One- and two-dimensional CdII coordination polymers constructed from 2-(2-methyl-1 H-benzimidazol-1-yl)acetate ligands.

The one- and two-dimensional polymorphic cadmium polycarboxylate coordination polymers, catena-poly[bis[μ2-2-(2-methyl-1 H-benzimidazol-1-yl)acetato-κ3 N3: O, O′]cadmium(II)], [Cd(C10H9N2O2)2] n, and poly[bis[μ2-2-(2-methyl-1 H-benzimidazol-1-yl)acetato-κ3 N3: O, O′]cadmium(II)], also [Cd(C10H9N2O2)2] n, were prepared under solvothermal conditions. In each structure, each CdII atom is coordinated by four O atoms and two N atoms from four different ligands. In the former structure, two crystallographically independent CdII atoms are located on twofold symmetry axes and doubly bridged in a μ2- N: O, O′-mode by the ligands into correspondingly independent chains that run in the [100] and [010] directions. Chains containing crystallographically related CdII atoms are linked into sheets viaπ-π stacking interactions. Sheets containing one of the distinct types of CdII atom are stacked perpendicular to [001] and alternate with sheets containing the other type of CdII atom. The second complex is a two-dimensional homometallic CdII (4,4) net structure in which each CdII atom is singly bridged to four neighbouring CdII atoms by four ligands also acting in a μ2- N: O, O′-mode. A square-grid network results and the three-dimensional supramolecular framework is completed by π-π stacking interactions between the aromatic ring systems. [ABSTRACT FROM AUTHOR]