Syntheses, structures, luminescence and CO2 gas adsorption properties of four three-dimensional heterobimetallic metal–organic frameworks.

A new pyridyl-tricarboxylic acid ligand, 4,4'-(6-carboxypyridine-2,4-diyl)dibenzoic acid (H 3 L), was used to construct one zero-dimensional (0D) complex, [Co(H 2 L) 2 (H 2 O) 2 ]•2H 2 O (1), and four isostructural three-dimensional (3D) heterobimetallic metal-organic frameworks (MOFs), [MNa(L)(H 2 O)] n •solvents (M ​= ​Co (2), Ni (3), Cu (4) and Zn (5)). The dimensionality ranging from 0D complex (1) to 3D frameworks (2 – 5) should be ascribed to various solvents (from MeCN to DMA/DMF) or whether presence of Na+ cation or not. Interestingly, isostructural 3D heterobimetallic MOFs 2 – 5 possess rhombic voids and reveal CO 2 gas adsorption features. Because heterobimetallic MOFs 2 and 5 possess higher framework stability than 3 and 4 , 2 and 5 exhibit higher CO 2 adsorption capacities at 273 ​K. Furthermore, photoluminescence properties of 1 – 5 have also been investigated. The present work provides a promising approach to design and construct heterobimetallic MOFs containing alkali-metal cations, and then to tune CO 2 adsorption properties. Four isostructural three-dimensional heterobimetallic metal-organic frameworks reveal interesting CO 2 gas adsorption properties. [Display omitted] • New pyridyl-tricarboxylic acid ligand was successfully synthesized. • New 3D heterobimetallic metal-organic frameworks were constructed. • Effect of solvents/Na+ cations on structure/dimensionality. • CO 2 gas adsorption capacities concern framework stability of MOFs. [ABSTRACT FROM AUTHOR]