The modular and isoreticular nature of metal-organic frameworks (MOFs) permits the exploration of structural frameworks that allow for control over the ligand environment. This allows for tuning the ligand’s interactions with neighbouring moieties within the MOF. Conventionally molecular rotors used as struts in MOFs are isolated to reduce or eliminate interactions with their environment towards achieving fast rotary dynamics. Inserting bicyclo[1.1.1]pentandioate (FTR) rotors into a cubic framework yielded isolated rotors with an energy barrier for rotation of a couple of calories per mole (Fig 1 A).[1] The outstanding synthetic versatility of MOFs allows us to insert the FTR rotors into a pillar-and-layer Zn-MOF and a geminal fluorinated FTR rotor into an Al-MOF where the rotors can interact with their neighbours. Contrary to expectations, these rotors navigate the rotational potential energy landscape in such a way as to produce co-rotating pairs of rotors or geared molecular rotors. These geared molecular rotors have very low energy barriers for rotation (24 cal/mol) owing to the synchroneity of their rotation.[2] Additionally, the dipolar FTR-F2 rotor in the Al-MOF forms layers of interacting rotors oriented in different configurations. Interconversion between the different rotor configurations is achieved by the highly dynamic cooperative reorientation cascade of the dipolar rotors with a very low barrier for reorientation of ca. 17 cal/mol (Fig 1 B). [3] References [1] J. Perego, S. Bracco, M. Negroni, C. X. Bezuidenhout, G. Prando, P. Carretta, A. Comotti, P. Sozzani Nature Chem. 2020, 12, 845. [2] J.Perego, C. X. Bezuidenhout, S. Bracco, G. Prando, L. Marchiò, M. Negroni, P. Carretta, P. Sozzani, and A. Comotti JACS 2021 143 (33), 13082-13090. [3] Perego, J.; Bezuidenhout, C. X.; Bracco, S.; Piva, S.; Prando, G.; Aloisi, C.; Carretta, P.; Kaleta, J.; Le, T. P.; Sozzani, P.; Daolio, A.; Comotti, A., Angew. Chem. Int. Ed 2023, 62, e202215893.
Bezuidenhout, C., Perego, J., Daolio, A., Bracco, S., Piva, S., Sozzani, P., et al. (2023). Molecular Rotor Dynamics in Metal–Organic Frameworks at Extremely Low Temperatures. In Abstracts Book 5th European Conference on Metal Organic Frameworks and Porous Polymers (EuroMOF2023), Granada 2023 (pp.326-326). EuroMOF.
Molecular Rotor Dynamics in Metal–Organic Frameworks at Extremely Low Temperatures
Bezuidenhout, CX
;Perego, J;Daolio, A;Bracco, S;Piva, S;Sozzani, P;Comotti, A
2023
Abstract
The modular and isoreticular nature of metal-organic frameworks (MOFs) permits the exploration of structural frameworks that allow for control over the ligand environment. This allows for tuning the ligand’s interactions with neighbouring moieties within the MOF. Conventionally molecular rotors used as struts in MOFs are isolated to reduce or eliminate interactions with their environment towards achieving fast rotary dynamics. Inserting bicyclo[1.1.1]pentandioate (FTR) rotors into a cubic framework yielded isolated rotors with an energy barrier for rotation of a couple of calories per mole (Fig 1 A).[1] The outstanding synthetic versatility of MOFs allows us to insert the FTR rotors into a pillar-and-layer Zn-MOF and a geminal fluorinated FTR rotor into an Al-MOF where the rotors can interact with their neighbours. Contrary to expectations, these rotors navigate the rotational potential energy landscape in such a way as to produce co-rotating pairs of rotors or geared molecular rotors. These geared molecular rotors have very low energy barriers for rotation (24 cal/mol) owing to the synchroneity of their rotation.[2] Additionally, the dipolar FTR-F2 rotor in the Al-MOF forms layers of interacting rotors oriented in different configurations. Interconversion between the different rotor configurations is achieved by the highly dynamic cooperative reorientation cascade of the dipolar rotors with a very low barrier for reorientation of ca. 17 cal/mol (Fig 1 B). [3] References [1] J. Perego, S. Bracco, M. Negroni, C. X. Bezuidenhout, G. Prando, P. Carretta, A. Comotti, P. Sozzani Nature Chem. 2020, 12, 845. [2] J.Perego, C. X. Bezuidenhout, S. Bracco, G. Prando, L. Marchiò, M. Negroni, P. Carretta, P. Sozzani, and A. Comotti JACS 2021 143 (33), 13082-13090. [3] Perego, J.; Bezuidenhout, C. X.; Bracco, S.; Piva, S.; Prando, G.; Aloisi, C.; Carretta, P.; Kaleta, J.; Le, T. P.; Sozzani, P.; Daolio, A.; Comotti, A., Angew. Chem. Int. Ed 2023, 62, e202215893.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
