Variation of topologies and entanglements in metal-organic frameworks with mixed tris[4-(1H-imidazol-1-yl)phenyl]phosphine oxide and dicarboxylate ligands

Six metal-organic frameworks with the combination of a novel tripodal ligand tris[4-(1H-imidazol-1-yl)phenyl]phosphine oxide (tipo) and different polycarboxylates, namely [Zn-2(bpdc)(2)(tipo)(H2O)]5H(2)O (1), [Cd(tipo)(2)][Cd-2(bdc)(3)]4H(2)O (2), [Cd-2(ndc)(2)(tipo)(2)]3H(2)O (3), [Cd-2(bpedc)(2)(tipo)(2)]15H(2)O (4), [Cd-2(hfdc)(2)(tipo)(2)]10H(2)O (5) and [Ni-2(tipo)(2)(bpedc)(H2O)(4)]2NO(3)2DMF (6), were synthesized and structurally characterized. Compound 1 featured a 2D 3D parallel polycatenation of a 3,3,4-connected net with an unusual 4 degrees of catenation and an index of separation of 2. Compound 2 showed an unprecedented polycatenation of charged networks 2D kgd and 3D pcu constructed by different organic ligands. Compound 3 exhibited a combination of a 2D 3D parallel polycatenation of the sql net and polythreading. Compound 4 featured a 4-fold interpenetration of a 3,5-connected 3,5T1 net. Compound 5 displayed an unusual 2-fold interpenetration of the sdd net. Compound 6 presented a 2-fold interpenetration of the 3,4-connected bey net with a cationic framework. The luminescence properties of 1-5 in the solid state were investigated. Also, compound 6 showed a tendency for rapid selective dye capture and highly efficient Cr2O72- removal from aqueous solution.