An antiferromagnetic metalloring pyrazolate (Pz) framework with [Cu12(μ2-OH)12(Pz)12] nodes for separation of C2H2/CH4 mixture

Abstract

The search for functional metalloring organic frameworks (MROFs) has been of continuous interest in the fields of both molecular rings and metal–organic frameworks (MOFs) due to their importance in many multifunctional applications. Herein, a hierarchical pyrazolate framework MROF-12 with the topology of the Schläfli symbol {4⁶⁰.6⁶} is reported, which is constructed by an elongated rigid ligand and attractive metalloring cluster nodes [Cu₁₂(μ₂-OH)₁₂(Pz)₁₂]. MROF-12 not only adopts the unique functionalities of the metalloring clusters but also inherits the porous properties of MOFs. The large [Cu₁₂(μ₂-OH)₁₂(Pz)₁₂] metalloring nodes with the diameter of 12.202 Å endow MROF-12 with excellent stability and antiferromagnetism, and they are bridged by linear pyrazolate ligands (H₂NDI) to form micro–mesoporous MROF with permanent porosity. The activated sample MROF-12a can exhibit a relatively high Brunauer–Emmett–Teller/Langmuir surface area (460.7/571.9 m² g⁻¹) as well as pore volume of 0.240 cm³ g⁻¹. Dynamic fixed bed breakthrough experiments indicate that the separation of C₂H₂/CH₄ or CO₂/CH₄ mixtures can be efficiently achieved through a column packed with MROF-12a solid.