Dynamic Characterization of Crystalline Supramolecular Rotors Assembled through Halogen Bonding

作者：Catalano Luca; Perez Estrada Salvador; Terraneo Giancarlo^*; Pilati Tullio; Resnati Giuseppe; Metrangolo Pierangelo; Garcia Garibay Miguel A

来源：Journal of the American Chemical Society, 2015, 137(49): 15386-15389.

DOI：10.1021/jacs.5b10776

A modular molecular kit for the preparation of crystalline molecular rotors was devised from a set of stators and rotators to gain simple access to a large number of structures with different dynamic performance and physical properties. In this work, we have accomplished this with crystalline molecular rotors self-assembled by halogen bonding of diazabicyclo[2.2.2]octane, acting as a rotator, and a set of five fluorine-substituted iodobenzenes that take the role of the stator. Using variable-temperature H-1 T-1 spin-lattice relaxation measurements, we have shown that all structures display ultrafast Brownian rotation with activation energies of 2.4-4.9 kcal/mol and pre-exponential factors of the order of (1-9) x 10(12) s(-1). Line shape analysis of quadrupolar echo H-2 NMR measurements in selected examples indicated rotational trajectories consistent with the 3-fold or 6-fold symmetric potential of the rotator.

• 出版日期2015-12-16