Structure and properties of zinc 1,3-bdc metal-organic frameworks

Thesis

Complexity in material design is widely recognised as a means of introducing unique properties that may be beneficial for various applications. The project described in this thesis aims to explore the efficiency of introducing such complexity into materials through the incorporation of low-symmetry components. Due to their ability of offering control over the geometry of building blocks, metal-organic frameworks (MOFs) were selected as the platform for this exploration.

The presented results revolve around the structures and chemical/physical properties of five crystalline MOFs obtained by combining zinc with the low-symmetry bent linker 1,3-benzene dicarboxylic acid (1,3-bdc): TRUMOF-1, MOX-2, MOX-3, MOX4, and MOX-5. As highlighted in Chapter 3, these structures exhibit significant disparity in their topologies, with that of TRUMOF-1 being particularly intriguing due to its aperiodic nature.

The true structure of TRUMOF-1, as described in Chapter 7, was characterised using a Truchet-tile analogy. Its maze-like pore network was found to adsorb different types of gases and, more interestingly, enhance its elastic stability through the internal reorganisation of different local motifs. Being the first topologically aperiodic material to be reported, TRUMOF-1 likely possesses many other interesting properties with the potential for various applications, including error-correcting memory storage.

Our findings ultimately confirm the efficacy of incorporating low-symmetry components in obtaining complex materials. The role of 1,3-bdc in introducing this complexity, both through its bent shape and the flexibility of the carboxylate torsion angles, is discussed in Chapter 8.

Yet, there is still a need for a systematic approach to purposely synthesise complex structures such as TRUMOF-1. The difficulty in finding suitable synthetic parameters, together with the ultimate goal of controlling the complexity, are important aspects to focus on in future research.

Authors: Meekel, EG

• DOI: 10.5287/ora-m88pjanz8
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: Monte-Carlo; metal-organic frameworks; crystallography; diffuse scattering; inorganic chemistry
• Subjects: Chemistry, Inorganic; Monte Carlo method; Crystallography; Metal-organic frameworks; Materials