Cobalt phenylenediacetate coordination polymers containing long-spanning dipyridyl ligands: rectangular grid, primitive cubic, and 5-connected Archimedean layered net topologies

Abstract

Divalent cobalt coordination polymers containing both phenylenediacetate (phda) and bis(4-pyridylmethyl)piperazine (4-bpmp) ligands display differing dimensionalities and topologies. The para-substituted 1,4-phda ligand afforded {[Co(1,4-phda)(4-bpmp)(H₂O)₂]·2H₂O}_n (1), a layered phase with standard (4,4) rhomboid grid topology. Use of the meta-substituted 1,3-phda ligand generated [Co(1,3-phda)(4-bpmp)]_n (2), which has [Co(1,3-phda)]_n layers pillared by pairs of 4-bpmp ligands into a three-dimensional (3D) coordination polymer with primitive cubic topology. Antiferromagnetically coupled {Co₂(CO₂)₂} dinuclear units (J = −2.04(4) cm⁻¹) are embedded within the structure of 2. The ortho-substituted derivative {[Co(1,2-phda)(4-bpmp)_1.5(H₂O)](H₂4-bpmp)_0.5(ClO₄)·12H₂O}_n (3) manifests an intriguing layered structure with 5-connected cobalt atom nodes and an Archimedean 3³4⁴5³cem topology with triangular and rectangular circuits.