Mild synthesis of rare-earth based MOF-76 series

MOF-76 is one example of a rare-earth (RE) based metal-organic framework (MOF) and has potential applications in catalysis and guest sorption, among others. RE-MOFs are commonly synthesized under solvothermal conditions using high boiling point polar solvents such as N,N-dimethylformamide (DMF), which is known to be harmful to health and environment. Moreover, this solvent is strongly coordinating and has a high boiling point, making it hard to remove. As the synthesis of MOFs under more sustainable conditions is desirable and is one of our research interests, we studied the possibility of conducting the synthesis of such MOF-76 in ethanol as a greener and less coordinating solvent. We firstly optimized the synthesis of MOF-76 with La as model metal, since it is one of the cheapest rare earths, investigating different precursor concentrations and reactions temperatures. We observed that in this solvent the formation of sea urchin-shaped aggregates of crystals is preceded by the formation of a gel. After the optimization of the reaction conditions with lanthanum, we expanded the scope of our approach to other rare earths (Ce, Pr, Nd, Sm, Eu, Er and Yb), as well as to bimetallic MOFs containing Tb and Eu. Crystalline compounds, with crystallite sizes and shapes linked to the nature of the RE metal, were obtained with all the above-mentioned metals. However, the MOF-76 topology was only observed for the three largest (Ce, Pr, Nd) and the smallest (Yb) lanthanides, forming as sea-urchin shaped aggregates, while a different, unidentified crystalline phase was obtained for Eu, Sm, and Nd.

Affiliations

UCLouvainSST/IMCN/MOST - Molecular Chemistry, Materials and Catalysis

Citations

APA
Chicago
FWB

Steenhaut, T., Crits, R., Hermans, S., & Filinchuk, Y. (2022). Mild synthesis of rare-earth based MOF-76 series. Nucleation: multiple pathways, multiple outcomes, Brussels, Belgium. https://hdl.handle.net/2078.5/249031