Benchmark Dynamics of Dipolar Molecular Rotors in Fluorinated Metal-Organic Frameworks |
| |
Authors: | Dr Jacopo Perego Dr Charl X Bezuidenhout Prof Silvia Bracco Dr Sergio Piva Dr Giacomo Prando Cristian Aloisi Prof Pietro Carretta Dr Jiří Kaleta Thi Phuong Le Prof Piero Sozzani Dr Andrea Daolio Prof Angiolina Comotti |
| |
Institution: | 1. Department of Materials Science, University of Milano - Bicocca, Via R. Cozzi 55, 20125 Milan, Italy;2. Department of Physics, University of Pavia, Via Bassi 6, 27100 Pavia, Italy;3. Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo námĕstí 542/2, 16000 Prague, Czech Republic |
| |
Abstract: | Fluorinated Metal-Organic Frameworks (MOFs), comprising a wheel-shaped ligand with geminal rotating fluorine atoms, produced benchmark mobility of correlated dipolar rotors at 2 K, with practically null activation energy (Ea=17 cal mol−1). 1H T1 NMR revealed multiple relaxation phenomena due to the exchange among correlated dipole-rotor configurations. Synchrotron radiation X-ray diffraction at 4 K, Density Functional Theory, Molecular Dynamics and phonon calculations showed the fluid landscape and pointed out a cascade mechanism converting dipole configurations into each other. Gas accessibility, shown by hyperpolarized-Xe NMR, allowed for chemical stimuli intervention: CO2 triggered dipole reorientation, reducing their collective dynamics and stimulating a dipole configuration change in the crystal. Dynamic materials under limited thermal noise and high responsiveness enable the fabrication of molecular machines with low energy dissipation and controllable dynamics. |
| |
Keywords: | Crystal Engineering Fluorine Metal Organic Frameworks Molecular Dynamics Molecular Rotor |
|
|