Solvent-induced diversity of luminescent metal organic frameworks based on different secondary building unitst

摘要

By using a symmetrical V-shaped rigid 5'-carboxyl-(1,1'-3',1"-terphenyl)-4,4"-dicarboxylic acid (H3L), three Cd(u)-based metal-organic frameworks (MOF5), [Cd-3(L)(2)(H2O)(4)].DMF (1), [Cd-2(L)(SO4)(2)].3(Me)(2)NH2 (2) and [Cd(HL)(H2(O))].0.5H(2)O (3), have been synthesized under solvothermal conditions. Due to the reactions in different solvent systems, L3-/HL2- in 1-3 show different coordination modes with Cd(u) ions to form various secondary building units (SBUs) in the final structures. The desolvated structure of 1 (1a) contains two shapes of 1D channels with suitable pore sizes. 2 is a 3D dense packing pattern with a three nodal (5,6,7)-connected new topological net, and 3 is a 2D layered (4,4) -connected sql network connected with partly deprotonated HL2- ligands. As a result, la possesses not only high CO2 loading but also excellent CO2/CH4 selectivity. In addition, all complexes display solid-state luminescence stemming from ligand-to-metal charge transfer.