Origin of the isotropic motion in crystalline molecular rotors with carbazole stators. Issue 16 (20th March 2019)

• Record Type: Journal Article
• Authors: Colin-Molina, Abraham; Jellen, Marcus J.; García-Quezada, Eduardo; Cifuentes-Quintal, Miguel Eduardo; Murillo, Fernando; Barroso, Jorge; Pérez-Estrada, Salvador; Toscano, Rubén A.; Merino, Gabriel; Rodríguez-Molina, Braulio
• Is Part Of: Chemical science. Volume 10:Issue 16(2019)
• Page Start: 4422
• Page End: 4429
• Publication Date: 2019-03-20
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8sc04398a
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Herein we report two crystalline molecular rotors1 and4 that show extremely narrow signals in deuterium solid-state NMR spectroscopy. Abstract : Herein we report two crystalline molecular rotors1 and4 that show extremely narrow signals in deuterium solid-state NMR spectroscopy. Although this line shape is typically associated with fast-moving molecular components, our VT 2 H NMR experiments, along with X-ray diffraction analyses and periodic DFT computations show that this spectroscopic feature can also be originated from low-frequency intramolecular rotations of the central phenylene with a cone angle of 54.7° that is attained by the cooperative motion of the entire structure that distorts the molecular axis to rotation. In contrast, two isomeric structures (2 and3 ) do not show a noticeable intramolecular rotation, because their crystallographic arrays showed very restricting close contacts. Our findings clearly indicate that the multiple components and phase transitions in crystalline molecular machines can work in concert to achieve the desired motion.