Molecular rotors are a class of crystalline organic materials that may feature macroscopic properties such as emission, gas absorption, or volatile species, as well as the transduction of thermal energy into mechanical energy. Also, it is reported that these properties can be controlled by regulating the movement of their molecular components. However, for the accurate control of these properties, it is essential to understand how these molecules move within the crystal. For this purpose, various experimental techniques are used to describe the angularity and frequency of rotational movement in the solid-state. Some include single-crystal X-ray diffraction, and in particular, nuclear magnetic resonance in the solid-state at variable temperature, in which nuclei such as 13C and 2H are examined. The data obtained by these analyses allow determining the geometric variation as the system moves, as well as its activation parameters. Nevertheless, these techniques have detection constraints that limit the understanding of the molecular motion in solids. However, through electronic structure computations, it is possible to obtain not only the rotational potential and the transition states involved in the internal movement of the crystal's components, but also to gain a better insight into the interactions that occur during rotation. The first results that we have obtained are:
1) A. Aguilar-Granda, A. Colin-Molina, M. J. Jellen, A. Núñez-Pineda, M. Eduardo Cifuentes-Quintal, R. A. Toscano, G. Merino, B. Rodríguez-Molina "Triggering the Dynamics of a Carbazole-p-[phenylene-diethynyl]- xylene Rotor through a Mechanically Induced Phase Transition" Chem. Commun. 2019, 55, 14054-14057. Impact factor: 6.164
2) A. Colin-Molina, M. Jellen, E. García-Quezada, E. Cifuentes-Quintal, F. Murillo, J. Barroso, S. Pérez-Estrada, R. A. Toscano, G. Merino, B. Rodríguez-Molina "Origin of the Isotropic Motion in Crystalline Molecular Rotors with Carbazole Stators" Chem. Sci. 2019, 10, 4422-4429. Impact factor: 9.556
If you are interested in this topic, we need a graduate student (master's or Ph.D.) to model in the solid-state these rotors synthesized at Dr. Braulio Rodriguez-Molina's lab. The thesis may be elaborated at the Instituto de Química (UNAM) or at the Cinvestav Mérida.