Impact of counteranion on the self-assembly of Cd(II)-containing MOFs: Syntheses, structures and photoluminescent properties

Three Cd(II)-containing metal–organic frameworks based on 1,1′-(1,5-pentanediyl)bis-1H -benzimidazole (pbbm), namely, View the MathML source{[Cd(NO3)(pbbm)2]2·(NO3)2·H2O}n(1), [CdSO4(pbbm)2]n (2) and [CdI2(pbbm)]2 (3) are prepared systematically by using hydrothermal technique to examine the effects of counteranion on the topology of the resultant network. In complexes 1 and 2, pbbm acts as a bidentate ligand to link two Cd atoms to result in two different 1D chain structures. Complex 3 has a dimeric structure in which two Cd(II) cations are bridged by two pbbm ligands. The significant differences of these MOFs indicate that the counteranions have great impact on the assembling and structures of the resultant MOFs. The photoluminescent properties of these new materials have been studied in the solid state at room temperature. Further investigation reveals that their photoluminescent characteristics obtained from experiments accord with the computed parameters.