A copper based pillared-bilayer metal organic framework: its synthesis, sorption properties and catalytic performance

Abstract

A new 2D pillared-bilayer flexible open metal organic framework {[Cu(tdc)(bpe)]_n·2n(H₂O)·n(MeOH)} (compound 1) [H₂tdc = 2,5 thiophenedicarboxylic acid; bpe = 1,2-bis(4-pyridyl)ethane] has been synthesized through a solvent diffusion technique and structurally characterized. The structure analysis reveals that the tdc ligands formed bilayers with the Cu(II) ions along the b-direction and the layers are further pillared by bpe linkers and resulted in a 2D pillared-bilayer porous framework with a four connected uninodal sq1/Shubnikob tetragonal plane net with the Schälfli symbol {4⁴·6²}. The framework is enclosed with large square shaped channels (13.7 × 8.35 Ų) along the bc-plane and the channels are occupied by guest solvent molecules. The adsorption studies reveal that compound 1 shows selective adsorption for CO₂ over CH₄ at room temperature and it also shows hysteretic sorption for a few protic solvents (H₂O and EtOH) and a Type-1 isotherm for an aprotic solvent (CH₃CN). The catalytic performance of compound 1 for Glaser type homo-coupling reactions has also been reported.