Structural diversity, magnetic property, or luminescence sensing of Co(ii) and Cd(ii) coordination polymers derived from designed 3,3'-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid.

Five novel coordination polymers (CPs), formulated as {[Co(μ-cpboda)(μ-OH)(2,2-bipy)]·1.5DMF·2HO} (1), {[Co(μ-cpboda)(4,4'-bpy)(HO)]·4HO} (2), {[Co(μ-Hcpboda)(1,4-bib)(HO)]·HO·DMF·1.5HCOOH} (3), [Cd(μ-Hcpboda)(1,4-bib)] (4), and {[Cd(μ-cpboda)(μ-OH)(phen)]·2DMF·1.5HO} (5) (Hcpboda = 3,3'-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid, 2,2-bipy = 2,2-bipyridine, 4,4'-bpy = 4,4'-bipyridine, 1,4-bib = 1,4-di(1H-imidazol-1-yl)benzene, phen = 1,10-phenanthroline) have been synthesized under solvothermal conditions and characterized by elemental analyses (EAs), single-crystal X-ray diffraction analyses, X-ray powder diffraction analyses (PXRD), FT-IR spectra, and thermogravimetric analyses (TGAs). The structural analyses reveal that these complexes have four 2D coordinate polymers and one 3D framework, in which metal ions are in octahedral coordination geometries in 1-3 and 5, but seven-coordinated disordered pentagonal bipyramids in 4. Complexes 1 and 5 represent linear trinuclear [M(μ-OH)(μ-COO)] SBUs in 1 (M = Co(ii)) and in 5 (M = Cd(ii)) based on a 3,4,6-connected net with a point symbol (3·4)(3·8·9)(3·4·8·9·10) net, complex 2 exhibiting a (3-c)(4-c)(4-c) 3D structure with the (5·6·8·9)(5·6·9)(5·6) topology and complexes 3 and 4 having a novel 2D framework with the point symbol of (4·6). Magnetization analyses disclose the antiferromagnetic (AF) behaviors between Co(ii) ions in complexes 1 & 3 and S = 3/2 (Co) spin Heisenberg chains with alternating magnetic sequences (F/F/AF) in 2. Fluorescence measurements indicate that 4 and 5 are promising luminescence sensors for the detection of CrO and CrO anions in aqueous solution.