Multidynamic Crystalline Molecular Rotors Comprising an N‐Heterocyclic Carbene Binuclear Au(I) Complex Bearing Multiple Rotators

Abstract

AbstractWe report multidynamic molecular rotations in crystals using a concave‐shape N‐heterocyclic carbene (NHC) binuclear Au(I) complex rotor bearing pyrazine and tetrahydrofuran (THF) molecules as multicomponent rotators. Single‐crystal X‐ray diffraction (XRD) measurements revealed that two THF molecules are located near the central pyrazine encapsulated by two bulky NHC ligands. From 2H solid‐state NMR analysis, it was observed that the pyrazine rotated in a 2‐fold site exchange with a 180° rotational angle and a 31 kJ mol−1 energy barrier, while the THF molecules showed a 23°‐38° libration with a lower energy barrier (14 kJ mol−1). Interestingly, the pyrazine rotation was accelerated when the THF molecules rotated in fast site exchange with a large angle of libration, suggesting that the rotators exhibit multidynamics in a correlated manner.