Two 1D Chain Polymers Constructed by 5-Bromoisophthalate and Bis(Imidazole) Ligands: Syntheses, Crystal Structures, and Photoluminescence Properties

Abstract

Employing 5-bromoisophthalate(5-Br-H₂ip) and different spacers, two new 1D coordination polymers, [Zn(5-Br-ip)(pbbm)(H₂O)] _n (1) and {[Cd(5-Br-ip)Cl(H₂O)](H₂bpp)_0.5} _n (2) (pbbm = 1,1’-(1,3-propanediyl)bis(benzimidazole, bpp = 1,3-bis(4-pyridyl)propane), were synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction, elemental analysis, and IR spectrum. X-ray diffraction reveals that complex 1 crystallizes in the triclinic crystal system, space group P-1, with a = 9.570(4)Å, b = 10.216(4)Å, c = 14.104(5)Å, α = 72.737(4)°, β = 78.811(5)°, γ = 66.531(4)°, and Z = 2. Complex 2 also crystallizes in the triclinic crystal system, space group P-1, with a = 8.803(4)Å, b = 9.512(4)Å, c = 10.099(4)Å, α = 115.283(4)°, β = 96.272(5)°, γ = 91.594(5)°, and Z = 2. Complex 1 exhibits a 1D double chain structure with loops interlocked by pbbm ligands, while complex 2 shows a 1D double chain bridged by chlorine ions. The significant differences of these complexes suggest that metal ions and spacers have remarkable impact on the assembling and structures of the resultant products. In addition, the result about photoluminescence experiment backs the fact up that the heavy anions can lead to the quenching of photoluminescence signal.

Keywords:

• 5-bromoisophthalic acid
• crystal structure
• photoluminescence property