Porous coordination polymers based on functionalized Schiff base linkers: enhanced CO2 uptake by pore surface...

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Porous coordination polymers (PCPs) are advanced materials with tunable structures and properties.
• Mixed-linker systems offer a versatile approach to designing novel PCP frameworks.
• Understanding structure-property relationships is crucial for developing materials with specific adsorption capabilities.

Purpose of the Study:

• To synthesize and characterize new mixed-linker porous coordination polymers.
• To investigate the impact of pore surface modification on gas adsorption properties, particularly CO2 uptake.
• To explore the role of linker choice in controlling framework interpenetration and porosity.

Main Methods:

• Synthesis of three new porous coordination polymers using dicarboxylate and Schiff base linkers.
• Structural characterization via X-ray diffraction to determine 3D coordination frameworks.
• Adsorption studies to evaluate CO2 and water vapor uptake capacities.
• Single-crystal-to-single-crystal transformations were observed and analyzed.

Main Results:

• Three novel 3D coordination polymers, {[Cu(Meazpy)0.5(glut)](H2O)}n (2), {[Zn(azpy)0.5(terep)](H2O)}n (3), and {[Zn(Meazpy)0.5(terep)]}n (4), were successfully synthesized.
• Compound 2, featuring a methyl-modified Schiff base linker, exhibited a 50% enhancement in CO2 uptake compared to a similar framework (compound 1) lacking the methyl group.
• Framework interpenetration was controlled by linker selection, with glutarate leading to non-interpenetrated structures, unlike terephthalate which resulted in interpenetrated frameworks.

Conclusions:

• Pore surface modification via methyl group incorporation in Schiff base linkers is an effective strategy for enhancing CO2 adsorption in porous coordination polymers.
• The choice of dicarboxylate linker significantly influences the framework topology, allowing for control over interpenetration and porosity.
• These findings contribute to the rational design of advanced porous materials for gas storage and separation applications.