Molecular rotors offer a platform to realize controlled dynamics and modulate the functions of solids. The motional mechanisms in arrays of rotors have not been explored in depth. Crystal-like porous organosilicas, comprising p-phenylene rotators pivoted onto a siloxane scaffold, were modelled using molecular dynamics (MD) simulations. Long simulations, on a microsecond scale, allowed to follow the reorientation statistics of rotor collections and single out group configurations and frequency distributions as a function of temperature. The motions observed in the MD simulations support a multiple-site model for rotor reorientations. Computed motional frequencies revealed a complex rotatory phenomenon combining an ultra-fast libration motion (oscillation up to 30°) with a slow and fast 180° flip reorientation. Adopting a multiple-site model provides a more accurate simulation of the 2H-NMR spectra and a rationalization of their temperature dependence. In particular, rotators endowed with distinct rates could be explained by the presence of slower rings locked in a T-shaped conformation.

De Nicola, A., Correa, A., Bracco, S., Perego, J., Sozzani, P., Comotti, A., et al. (2022). Collective dynamics of molecular rotors in periodic mesoporous organosilica: a combined solid-state 2H-NMR and molecular dynamics simulation study. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 24(2), 666-673 [10.1039/d1cp05013c].

Collective dynamics of molecular rotors in periodic mesoporous organosilica: a combined solid-state 2H-NMR and molecular dynamics simulation study

Bracco S.
Membro del Collaboration Group
;
Perego J.
Membro del Collaboration Group
;
Sozzani P.
Membro del Collaboration Group
;
Comotti A.
Membro del Collaboration Group
;
2022

Abstract

Molecular rotors offer a platform to realize controlled dynamics and modulate the functions of solids. The motional mechanisms in arrays of rotors have not been explored in depth. Crystal-like porous organosilicas, comprising p-phenylene rotators pivoted onto a siloxane scaffold, were modelled using molecular dynamics (MD) simulations. Long simulations, on a microsecond scale, allowed to follow the reorientation statistics of rotor collections and single out group configurations and frequency distributions as a function of temperature. The motions observed in the MD simulations support a multiple-site model for rotor reorientations. Computed motional frequencies revealed a complex rotatory phenomenon combining an ultra-fast libration motion (oscillation up to 30°) with a slow and fast 180° flip reorientation. Adopting a multiple-site model provides a more accurate simulation of the 2H-NMR spectra and a rationalization of their temperature dependence. In particular, rotators endowed with distinct rates could be explained by the presence of slower rings locked in a T-shaped conformation.
Articolo in rivista - Articolo scientifico
Dynamica, molecular rotors, 2H NMR, hybrid material, organosilica;
English
666
673
8
De Nicola, A., Correa, A., Bracco, S., Perego, J., Sozzani, P., Comotti, A., et al. (2022). Collective dynamics of molecular rotors in periodic mesoporous organosilica: a combined solid-state 2H-NMR and molecular dynamics simulation study. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 24(2), 666-673 [10.1039/d1cp05013c].
De Nicola, A; Correa, A; Bracco, S; Perego, J; Sozzani, P; Comotti, A; Milano, G
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/355059
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