Metal-organic frameworks and their applications in luminescent sensing and hydrocarbon separations
Creators: name: Velasco, Ever O.
Publisher: name: No Publisher Supplied
Year: 2022

description: Metal-Organic Frameworks (MOFs) are a versatile class of organic-inorganic highly crystalline and porous materials. Inorganic atoms (or clusters) are bridged together by organic linkers through coordinative bonds to form 3-dimentional extended networks. This class of porous materials are well-known for their ease of tunability and functionalization that originates from either modification to their inorganic or organic building blocks. The individual properties from either the inorganic or organic building blocks can be inherited by the resulting MOF material. These modifications allow this class of materials to be tailored to specific applications such as for gas separation and luminescent sensing. The individual interactions that occur between analytes and the host framework are always intricate, whether for gas separation or luminescent sensing, making complete control over the resulting frameworks challenging. The work summarized in this dissertation uses a combination of crystallographic, computational, and spectroscopic methods to understand the interactions that occur between the host frameworks and specific analytes for gas separation and luminescent detection of chemical species. This information was then used to design and use materials for the separation of C6 hydrocarbons, large scale production and the chemical detection of toxic chemical species. Zn-adtb is a robust, microporous MOF with excellent performance for adsorptive based separation of C6 hydrocarbons. This material can separate the linear isomer n-Hex from its branched isomers 3-methylpentane (3MP) and 2,3- dimethylbutane (23DMB) through a kinetic and molecular sieving mechanism, respectively to achieve higher octane rating in gasoline. One of the biggest drawbacks of MOFs for commercialization lie in the associated cost of the materials and their difficulty in large scale up synthesis. We demonstrate that Y-abtc, a MOF with excellent olefin/paraffin separation of C3 hydrocarbons, can be produced at the single one pot 100g scale. Furthermore, the breakthrough experiments at large scale show that the material can still produce polymer grade propylene (&gt;99.5%) suitable for the synthesis of plastics even after scaling up, demonstrating retention of both structure and property. A luminescent metal-organic framework (LMOF), Zr-tcbpe, was designed from an AIE chromophore linker for the selective detection of the neurotoxin Carbon Disulfide (CS2). The detection mechanism was revealed to be an electron transfer process while the interactions between CS2 and the Zr-SBU of the framework was elucidated for the first time. Finally, Zn-adtb (LMOF-341), is not only a microporous material capable of separating C6 hydrocarbons but it also exhibits luminescence and is capable of selectively sensing the toxin benzaldehyde through an electron transfer mechanism. Zn-adtb (LMOF-341) demonstrates the versatility of MOFs with its capability of separating C6 isomers but also being able to detect aldehyde-based toxins.