Ionic liquid templated novel porous anionic cobalt(II) coordination framework based on rod-shaped metal-carboxylate chains

A novel porous anionic cobalt(II) coordination framework based on rod-shaped metal-carboxylate chains, [BMI][Co₃(L)₂(HCOO)(H₂O)₂] (1) (H₃L = 3,4-bi(4-carboxyphenyl)-benzoic acid, [BMI]Br = 1-butyl-3-methylimidazolium bromide), has been prepared under the combination of solvothermal and ionothermal syntheses. [BMI]Br ionic liquid play a structure directing role and [BMI]⁺ cation is occluded into the ultimate structure. Complex 1 possesses 1D channels (11.4 × 13.6 Å) constructed by 1D cobalt(II)-carboxylate secondary building unit (SBU) and H₃L ligands. The study suggests that [BMI]Br, the kind of molecular solvents as well as the anion of the cobalt(II) salts all play key roles in the formation of the title anionic framework.