Ln−Co-Based Rock-Salt-Type Porous Coordination Polymers: Vapor Response Controlled by Changing the Lanthanide Ion

We synthesized new porous coordination polymers (PCPs) {Ln^III[Co^III(dcbpy)₃]·nH₂O} (Ln = La³⁺, Nd³⁺, Gd³⁺; H₂dcbpy = 4,4′-dicarboxy-2,2′-bipyridine) and characterized them by X-ray diffraction and vapor-adsorption measurements. These three Ln−Co-based PCPs have similar rock-salt types and highly symmetrical porous structure and show a reversible structural collapse−regeneration accompanied by water-vapor desorption−adsorption. Similar structural regeneration was also observed for the Gd−Co PCP upon exposure to MeOH and CH₃CN vapors, whereas the remaining two PCPs barely responded to organic vapors.