Temperature-Controlled Assembly/Reassembly of Two Dicarboxylate-Based Three-Dimensional Co(II) Coordination Polymers with an Antiferromagnetic Metallic Layer and a Ferromagnetic Metallic Chain.

Two new dicarboxylate-based three-dimensional cobalt coordination polymers, [Co(Memal)(bpe)(HO)] () and [Co(Memal)(bpe)] (), were synthesized from dimethylmalonic acid (H-Memal) in temperature-controlled solvothermal reactions. Lower temperatures (6080 °C) favored the formation of , while higher temperatures (120 °C) favored the production of 2. Compound is comprised of Co(II) corrugated layers linked by - carboxylate bridges from the Memal ligands and pillared through -monodentate bpe groups. Compound is comprised of a three-dimensional network involving one-dimensional Co-carboxylate chains bonded by antisymmetric µ-Memal ligands and aligned parallel to the [001] direction. The solvothermal retreatment of crystalline samples of in a DMF/HO solvent at 120 °C allowed the structural reassembly, with complete conversion within over 48 h. Magnetic analyses revealed that compound exhibits both spin-orbital coupling and antiferromagnetic interactions through a - carboxylate (Memal) bridge exchange pathway [Co-Co separation of 5.478 Å] and compound showed a ferromagnetic interaction resulting from the short Co-Co separation (3.150 Å) and the small Co-O-Co bridging angles (98.5° and 95.3°) exchange pathway which was provided by µ-Memal bridging ligand.