Nanoscale rotational dynamics of four independent rotators confined in crowded crystalline layers

We report a study where Car–Parrinello molecular dynamics simulations and variable-temperature (30–300 K) 1H spin–lattice relaxation time experiments nicely complement each other to characterize the dynamics within a set of four crystalline 1,4-diethynylbicyclo[2.2.2]octane (BCO) rotors assembled in...

Descripción completa

Detalles Bibliográficos
Autores: Rodríguez Fortea, Antonio, Canadell, Enric, Wzietek, Pawel, Lemouchi, Cyprien, Allain, Magali, Zorina, Leokadiya, Batail, Patrick
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2020
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/209336
Acceso en línea:http://hdl.handle.net/10261/209336
Access Level:acceso abierto
Palabra clave:Molecular dynamics
Nanotechnology
Organometallics
Relaxation time
Rotational flow
Spin-lattice relaxation
Descripción
Sumario:We report a study where Car–Parrinello molecular dynamics simulations and variable-temperature (30–300 K) 1H spin–lattice relaxation time experiments nicely complement each other to characterize the dynamics within a set of four crystalline 1,4-diethynylbicyclo[2.2.2]octane (BCO) rotors assembled in the metal–organic rotor, {Li+4(−CO2-Ph-BCO-py)4(H2O)8}·2DMF. The remarkable finding of this work is that, despite the individual rotational barriers of four rotors being indiscernible and superimposed in a broad relaxation process, we were able to unravel a strongly interrelated series of rotational motions involving disrotatory and conrotatory motions in pairs as well as rotational steps of single rotators, all three processes with similar, sizeable rotational barriers of 6 kcal mol−1. It is noteworthy that DFT molecular dynamics simulations and variable-temperature (30–300 K) proton spin–lattice relaxation time experiments deliver the same high value for the rotational barriers stressing the potential of the combined use of the two techniques in understanding rotational motion at the nanoscale.