Highly selective sorption of small hydrocarbons and photocatalytic properties of three metal-organic frameworks based on tris(4-(1H-imidazol-1-yl)phenyl)amine ligand.

By employing a tris(4-(1H-imidazol-1-yl)phenyl)amine (Tipa) ligand, three new metal-organic frameworks, [Zn2(Tipa)(4,4'-bpdc)1.5(H2O)(NO3)]·2(DMF)·H2O (1; 4,4'-bpdc = 4,4'-biphenyldicarboxylate, DMF = N,N-dimenthylformamide), [Cd(Tipa)Cl2]·2(DMF)·H2O (2), and [Co(Tipa)Cl2(H2O)]·DMF·H2O (3), have been synthesized solvothermally. Compound 1 features a three-dimensional (3D) pillared-layer structure with low band gap and interesting photocatalytic properties. Compound 2 is a 2-fold interpenetrating (3,6)-connected porous framework, and it shows highly selective adsorption of C2H2, CO2, and C2H4 over CH4. Compound 3 with honeycomb-like layers exhibits unusual 2D + 2D→ 3D polycatenation (2D = two-dimensional). The luminescent properties for these compounds were also investigated.