Capture of volatile iodine by newly prepared and characterized non-porous [CuI]n-based coordination polymers

Four new non-porous CuI-coordination polymers [Cu2(μ3-I)2(μ-bpb)]n (1a), [Cu(μ2-I)(μ-bpb)]n (1b), [Cu4(μ2-I)4(μ-bpmb)4]n (2), and [CuI(μ-bdb)]n (3) (bpb = 1,4-bis(pyrazolyl)butane; bpmb = 1,4-bis[(pyrazolyl)methyl]benzene; bdb = 1,4-bis[(3,5-dimethylpyrazolyl)methyl]benzene) have been successfully prepared and their structures fully characterized by single-crystal X-ray diffraction, FT-IR spectroscopy, PXRD and elemental analysis. Crystallographic investigation revealed that 1a, 1b, and 2 exhibit two-dimensional (2D) structures; in 1a parallel [Cu2I2]n staircase motifs are cross-linked into two-dimensional sheets by bpb linkers with a fully extended conformation, while in the structures of 1b and 2 Cu2I2 rhomboid dimers are linked by bpb and pbmb ligands, respectively, into two-dimensional sheets with a 44-sql net. Differently, compound 3 shows a one-dimensional (1D) zigzag chain structure with monomeric CuI units. All the four non-porous coordination polymers show the ability to capture volatile iodine in the gas phase. The solid-state photoluminescence properties of 1a, 1b, and 2 have also been investigated. The iodine-adsorbed samples 1a-I2, 1b-I2, and 2-I2 show no fluorescence behavior.