Solvent-induced structural dynamics in noninterpenetrating porous coordination polymeric networks

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Porous coordination polymers (PCPs) and metal-organic frameworks (MOFs) are advanced materials with tunable structures and properties.
• Developing novel MOFs with specific functionalities, such as selective gas adsorption, is crucial for environmental and industrial applications.

Purpose of the Study:

• To synthesize and characterize new soft porous coordination polymer (PCP) or metal-organic framework (MOF) compounds.
• To investigate the guest exchange capabilities and gas adsorption properties of the synthesized MOFs.

Main Methods:

• Solvothermal synthesis of MOFs using a new rigid ligand, N-(4-pyridyl)-1,4,5,8-naphathalenetetracarboxymonoimide (PNMI), with Zn(II), Cd(II), and Mn(II) salts.
• Single-crystal X-ray diffraction to determine the crystal structures and net topology (rtl).
• Guest molecule exchange experiments and gas adsorption measurements (N2, H2, CO2).

Main Results:

• Three novel MOFs, [Zn(PNMI)], [Cd(PNMI)], and [Mn(PNMI)], were successfully synthesized.
• The MOFs feature one-dimensional rhombic channels and exhibit single-crystal to single-crystal (SCSC) guest exchange, with significant reductions in unit cell and void volumes.
• Activated Cd-based MOF (2) demonstrated selective CO2 uptake (278 cm²/g) over N2 and H2 at 1 bar and 196 K.

Conclusions:

• The synthesized MOFs possess dynamic structures capable of reversible guest exchange.
• The Cd-based MOF shows promise for selective carbon dioxide capture applications.
• The study highlights the potential of PNMI-based MOFs for gas separation and storage technologies.