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

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 {4(4)·6(2)}. The framework is enclosed with large square shaped channels (13.7 × 8.35 Å(2)) 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.