A series of 2D Cd(II) coordination polymers constructed from dicarboxylate acids and a flexible imidazole-based ligand

• Five 2D Cd(II)-based coordination polymers have been obtained.
• These coordination polymers reveal notable structural disparities.
• The structural differences are ascribed to the different dicarboxylate ligands.

Five new Cd(II)-based coordination polymers 1–5 with a flexible ligand 1,4-bis(2-methylimidazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene (bmimx) and five dicarboxylate acids (1,2-H2BDC = 1,2-benzenedicarboxylic acid, H2HMPH = homophthalic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, 1,3-H2ADA = 1,3-adamantanediacetic acid and H2ADI = adipic acid) have been synthesized under hydro(solvo)thermal conditions, namely, [Cd(bmimx)0.5(1,2-BDC)]n (1), {[Cd(bmimx)(HMPH)]·H2O}n (2), {[Cd(bmimx)(1,3-BDC)]·1.5H2O}n (3), {[Cd(bmimx)0.5(ADA)]·H2O}n (4) and {[Cd(bmimx)(ADI)]·2H2O}n (5). Structural analysis indicates that all the complexes exhibit 2D layer structures. Complexes 1 and 4 present binodal (3,4)-connected layers with 3,4L83 topology. Complex 2 displays a 44-sql layer with 1D helical chains, while 3 only shows a pleated net with the 44-sql topology. Complex 5 exhibits a sheet structure with hcb topology. The backbones of the dicarboxylate ligands play an important role in determining the structural diversity. Their thermal and luminescent properties are also discussed.

Five 2D Cd(II)-based coordination polymers have been obtained and characterized. Complexes 1 and 4 present binodal (3,4)-connected layers with 3,4L83 topology. Complexes 2 and 3 display 44-sql layers, of which 2 contains left- and right-handed helical chains. Complex 5 exhibits a sheet structure with hcb topology. Their thermal and luminescent properties were also investigated.Figure optionsDownload as PowerPoint slide