| Přispěvatelé: |
Jacopo Perego, Charl X. Bezuidenhout, Silvia Bracco,a Angiolina Comotti, Piero Sozzania, Perego, J, Bezuidenhout, C, Bracco, S, Comotti, A, Sozzani, P |
| Popis: |
Metal organic frameworks provide a versatile platform that can generate intriguing behaviours and innovative properties. Specifically, this contribution highlights our recent results related to the installation of highly dynamic molecular rotors in MOFs[1] and the development of fast scintillating MOFs and MOF/polymer composites for fast detection of high-energy radiations[2]. MOFs provide precise spatial disposition of organic struts and enough free volume to preserve the dynamic properties of molecular motors and rotors even in condensed matter. Molecular rotor bicyclo[1.1.1]pentane–dicarboxylate was installed in the 3D cubic structure of a highly porous zinc MOF[1] (figure A,B,C,D). Its dynamic behaviour was investigated with solid state NMR relaxation and muon-spin spectroscopy performed at temperatures as low as 2 K and molecular dynamic simulations, providing clear evidence of very fast molecular reorientation in the GHz regime even at the lowest temperatures, consistent with a low activation energy for rotational motion of 6.2 cal mol-1. High-Z MOFs were generated by coordination of zirconium-based clusters and highly emissive 9,10-bis(4-carboxyphenyl)anthracene (DPA) ligands allowing for the efficient sensitization of the linker fluorescence under high-energy radiation excitation (figure E,F). MOF nanocrystals were embedded in a continuous polymer matrix producing ultra-fast scintillators with rise time of ~ 50 ps and high light yields suitable for application as detectors for time-of-flight positron emission tomography (TOF-PET). [1] J. Perego, S. Bracco, M. Negroni, C. X. Bezuidenhout, G. Prando, P. Carretta, A. Comotti, and P. Sozzani, Nat. Chem. (2020), 12, 845. [2] J. Perego, I. Villa, A. Pedrini, E. C. Padovani, R. Crapanzano, A. Vedda, C. Dujardin, C. X. Bezuidenhout, S. Bracco, P. E. Sozzani, A. Comotti, L. Gironi, M. Beretta, M. Salomoni, N. Kratochwil, S. Gundacker, E. Auffray, F. Meinardi, A. Monguzzi, Nat. Photonics (2021) https://doi.org/10.1038/s41566-021-00769-z. |
