Bulky Ligands for Open Channels: Manganese (II) sql MOFs from Pyridyl-Functionalised [3]Polynorbornanes.

Area of Science:

• Materials Chemistry
• Supramolecular Chemistry
• Crystallography

Background:

• Metal-organic frameworks (MOFs) offer tunable porosity for diverse applications.
• Developing novel ligands is crucial for designing MOFs with specific structural and functional properties.

Purpose of the Study:

• To synthesize and characterize novel semi-linear, fused [n]polynorbornane-based aliphatic ligands.
• To construct isoreticular sql MOFs using these ligands and investigate their structural characteristics.
• To explore the potential for pore functionalization in the resulting MOFs.

Main Methods:

• Ligand synthesis: preparation of di-methyl ester (LMe) and di-ethyl ester (LEt) ligands.
• MOF synthesis: reaction of ligands with manganese nitrate under specific conditions.
• Crystal structure analysis: X-ray diffraction to determine the detailed structure and pore architecture of the MOFs.

Main Results:

• Successful synthesis of two novel polynorbornane-based ligands (LMe and LEt).
• Formation of two isoreticular sql topology MOFs with the formula [Mn(L)2(NO3)2].
• Crystal structures revealed large, non-interpenetrating pores with aligned 1D channels.
• Ester moieties of the ligands were observed to orient into the pore channels.

Conclusions:

• The synthesized ligands are effective building blocks for creating MOFs with significant porosity.
• The observed pore orientation of ester groups presents opportunities for post-synthetic modification and functionalization.
• These findings contribute to the design of customized MOFs for targeted applications.