Abstract
A cationic three-dimensional (3D) metal-organic framework (MOF) sustained by an N,N′-diethylformamide (DEF)-solvated zigzag-shaped Cd5 cluster secondary building unit (SBU), [Et2NH2]2[Cd5(BTB)4(DEF)2] ⋅ 4.75DEF (1 a, H3BTB=benzene-1,3,5-tribenzoic acid) shows flexible framework behavior and undergoes solvate exchange with CHCl3 to yield [Et2NH2]2[Cd5(BTB)4(DEF)2] ⋅ xCHCl3 (1 b) accompanied by changes to pore sizes and shapes. Unexpectedly, the DEF solvates coordinated to the central Cd2+ could not be replaced by strongly donor pyridyl and dipyridyl ligands. Additionally, more electron-deficient pyridyls preferentially coordinated to the flanking Cd2+ of the Cd5 SBU, as exemplified by [Et2NH2]2[Cd5(BTB)4(DEF)2(PyCHO)2] ⋅ xSol (2 a, PyCHO=4-pyridinealdehyde) and [Et2NH2]2[Cd5(BTB)4(DEF)2(PyAc)2] ⋅ xSol (2 b, PyAc=4-acetylpyridine). Density functional theory (DFT) calculations were used to understand these counterintuitive observations.
| Original language | English |
|---|---|
| Pages (from-to) | 503-509 |
| Number of pages | 7 |
| Journal | ChemPlusChem |
| Volume | 85 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 1 Mar 2020 |
Keywords
- cadmium
- clusters
- flexible metal–organic frameworks
- gas uptake
- ligand substitution