Dynamic Pore Space Partition in Zinc Metal-Organic Frameworks

Area of Science:

• Materials Chemistry
• Nanotechnology
• Chemical Engineering

Background:

• Framework connectivity is crucial for tuning metal-organic framework (MOF) properties like gas selectivity.
• Highly connected frameworks are common for M3 and Zr6 clusters, but rare for Zn4O tetramers, a foundational MOF building block.

Purpose of the Study:

• To explore the potential of pore space partition (PSP) to achieve higher connectivity in Zn4O-based MOFs.
• To synthesize and characterize a new family of Zn-pacs materials using PSP on the MOF-5-type system.
• To investigate the role of steric effects in the formation of highly connected Zn4O clusters.

Main Methods:

• Application of pore space partition (PSP) to the MOF-5-type system.
• Synthesis of a diverse family of Zn_x-pacs materials (x=2, 3, 4) with varying pore-partition mechanisms.
• Semiquantitative mapping of zinc-cluster chemistry within the pacs platform.

Main Results:

• Successful synthesis of a large family of Zn_x-pacs materials with Zn4O clusters exhibiting higher connectivity (>6).
• Discovery of a new pacs family based on 9-connected Zn4O, driven by steric effects and compressed hexagonal c/a ratios.
• Demonstrated broader applicability of PSP, removing the requirement for preoriented open-metal sites.

Conclusions:

• PSP is a powerful strategy to enhance framework connectivity in MOFs, particularly for Zn4O building blocks.
• The newly synthesized pacs materials exhibit improved aqueous stability and superior C2H2/C2H4 separation performance compared to non-partitioned counterparts.
• This work expands the scope of PSP and opens new avenues for designing advanced MOFs with tailored properties.