Two Novel Self-Catenated Metal–Organic Frameworks with Large Accessible Channels Obtained by a Mixed-Ligand Strategy: Adsorption of Dichromate and Ln3+ Postsynthetic Modification

Two novel metal–organic frameworks, namely [Cd3(bdc)­(HCOO)2(tipo)2(H2O)2]·2NO3·6DMF (1) and [Zn8(OH)4(bpdc)6(tipo)4]·16DMF (2) (tipo = tris­[4-(1H-imidazol-1-yl)­phenyl]­phosphine oxide, H2bdc = phenyl-1,4-dicarboxylic acid, H2bpdc = biphenyl-4,4′-dicarboxylic acid), have been successfully synthesized. Compound 1 exhibits a cationic 4,6-connected self-catenated framework with large 1D channels. Compound 2 features a 3,4-connected self-catenated framework with potential O donors located on the surface of the channels. Compound 1 shows a high adsorption for dichromate. Postsynthetic modification of 2 by lanthanide ions (Eu3+ and Tb3+) afforded fluorescent materials.