Our research focuses on tailoring the physical-chemical properties of metal-organic frameworks (MOFs) based on abundant and non-toxic metals to improve their affinity for carbon dioxide. Our work has a strong synthetic character: synthesis of new materials, development of new synthetic methodologies and manipulation of the structure of known materials equally fascinate us. This is paired with the interest in understanding the structure of materials at the atomic level and its relationship with their physical-chemical properties. Our core expertise in terms of characterisation techniques is X-ray diffraction, which we use for both structural elucidation of new materials and in situ investigation of structural behaviour under various stimuli. We have close collaborations with groups specialising in spectroscopy (infrared, solid-state nuclear magnetic resonance, X-ray absorption spectroscopy), gas/vapour adsorption and computational chemistry.
| Current research directions |
(Per-)fluorinated MOFs
MOFs with highly polar fluorine atoms exposed in the pores are known to display enhanced affinity for CO2, thanks to favourable interactions between the Lewis basic fluorines and the Lewis acidic carbon in CO2. Using (per-)fluorinated analogues of common organic linkers is likely to produce (per-)fluorinated versions of known frameworks and to obtain better sorbents for CO2 capture. In addition, (per-)fluorinated MOFs can display high hydrophobicity and maintain their CO2 capture performance also in humid conditions. The recent discovery of a perfluorinated Ce-based MOF with MIL-140A topology that displays excellent CO2 capture properties kickstarted our research in this area, which is currently expanding in several directions.
Relevant publications:
- Cooperative CO2 adsorption mechanism in a perfluorinated CeIV-based metal organic framework J. Mater. Chem. A 2023, 11, 5568-5583 [https://pubs.rsc.org/en/content/articlelanding/2023/ta/d2ta09746j]
- Increased CO2 Affinity and Adsorption Selectivity in MOF-801 Fluorinated Analogues ACS Applied Mater. Interfaces 2022, 14, 40801–40811 [https://pubs.acs.org/doi/10.1021/acsami.2c07640]
- Water-Based Synthesis and Enhanced CO2 Capture Performance of Perfluorinated Cerium-Based Metal-Organic Frameworks with UiO-66 and MIL-140 Topology ACS Sustainable Chem. Eng. 2019, 7, 394–402 [https://pubs.acs.org/doi/10.1021/acssuschemeng.8b03765]
Sustainable synthetic methods for the production of MOFs
MOFs are often synthesised in solvothermal conditions (high temperature, high pressure) in polar organic solvents, such as N,N-dimethylformamide (DMF) and similar solvents. In sight of their commercial deployment, it is paramount to be able to prepare large amounts of MOFs in an economically and environmentally sustainable way. We are actively pursuing the development of synthetic procedures for the production of various benchmark MOFs avoiding the use of expensive and environmentally hazardous solvents and high temperatures/pressures.
Representative publications:
- “Shake ‘n Bake” Route to Functionalized Zr-UiO-66 Metal–Organic Frameworks Inorg. Chem. 2021, 60, 14294–14301 [https://pubs.acs.org/doi/10.1021/acs.inorgchem.1c01839]
- In situ X‐ray Diffraction Investigation of the Crystallisation of Perfluorinated Ce(IV)‐based Metal‐Organic Frameworks with UiO‐66 and MIL‐140 architectures Chem. Eur. J. 2021, 27, 6579-6592 [https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202005085]
- Efficient Microwave Assisted Synthesis of Metal-Organic Framework UiO-66: Optimization and Scale Up Dalton Trans. 2015, 44, 14019-14026 [https://pubs.rsc.org/en/content/articlelanding/2015/dt/c5dt01838b]
Phosphonate-based MOFs
Most MOFs are based on carboxylates as organic linkers, whereas use of phosphonate linkers for construction of MOFs is not yet well established, due to synthetic and crystallographic challenges. However, the excellent robustness of metal phosphonates represents a significant advantage, if compared to conventional carboxylate-based MOFs, for practical applications and this fact alone makes metal phosphonates an attractive class of materials. The primary goal is to develop new phosphonate-based MOFs using linkers with high rigidity and non-linear shape. More recently, interest is also directed at "rediscovering" known metal phosphonates as sorbents for CO2 capture.
Relevant publications:
- Unusual adsorption-induced phase transitions in a pillared-layered copper ethylenediphosphonate with ultrasmall channels Mater. Adv., 2024, 5, 183-198 [https://pubs.rsc.org/en/content/articlelanding/2024/ma/d3ma00356f]
- Investigating the effect of positional isomerism on the assembly of zirconium phosphonates based on tritopic linkers Dalton Trans. 2020, 49, 3662-3666 [https://pubs.rsc.org/en/content/articlelanding/2020/DT/C9DT02463H]
- The first route to highly stable crystalline microporous zirconium phosphonate metal–organic frameworks Chem. Commun. 2014, 50, 14831-14834 [https://pubs.rsc.org/en/content/articlelanding/2014/cc/c4cc06223j
Defect engineering of Zr-based MOFs
Zirconium-based MOFs (Zr-MOFs) are a subclass of MOFs known for their remarkable stability, especially in the presence of water. It was recently discovered that Zr-MOFs can contain large amounts of structural defects without suffering from significant loss of stability and that defects are reactive sites towards exchange of terminal groups. The goal is to take advantage of the dynamic nature of defects in Zr-MOFs to introduce functional groups of various natures, allowing to explore a chemical variety that is not accessible through classical functionalisation routes that involve modification of the organic linkers.
Relevant publications:
- “Band gap modulation of zirconium-based metal-organic frameworks by defect engineering” J. Mater. Chem. A 2019, 7, 23781-23786 (Contribution on invitation for the Themed Issue “2019 Emerging Investigators”) [https://pubs.rsc.org/en/content/articlelanding/2019/ta/c9ta05216j]
- A new approach to enhancing the CO2 capture performance of defective UiO-66 via post-synthetic defect exchange” Dalton Trans. 2019, 48, 3349-3359 [https://pubs.rsc.org/en/Content/ArticleLanding/2019/DT/C9DT00154A]
- Post-Synthetic Ligand Exchange in Zirconium-Based Metal-Organic Frameworks: Beware of the Defects!” (‡Equal contributions) Angew. Chem. Int. Ed. 2018, 57, 11706-11710 [https://onlinelibrary.wiley.com/doi/full/10.1002/anie.201806910]
