《Hydrogen-Bonded Crystalline Molecular Machines with Ultrafast Rotation and Displacive Phase Transitions》 was written by Colin-Molina, Abraham; Jellen, Marcus J.; Rodriguez-Hernandez, Joelis; Cifuentes-Quintal, Miguel Eduardo; Barroso, Jorge; Toscano, Ruben A.; Merino, Gabriel; Rodriguez-Molina, Braulio. Formula: C12H7Br2N And the article was included in Chemistry – A European Journal in 2020. The article conveys some information:
Two new crystalline rotors 1 and 2 assembled through N-H···N hydrogen bonds by using halogenated carbazole as stators and 1,4-diaza[2.2.2]bicyclooctane (DABCO) as the rotator, are described. The dynamic characterization through 1H T1 relaxometry experiments indicate very low rotational activation barriers (Ea) of 0.67 kcal mol-1 for 1 and 0.26 kcal mol-1 for 2, indicating that DABCO can reach a THz frequency at room temperature in the latter. These Ea values are supported by solid-state d. functional theory computations. Interestingly, both supramol. rotors show a phase transition between 298 and 250 K, revealed by differential scanning calorimetry and single-crystal X-ray diffraction. The subtle changes in the crystalline environment of these rotors that can alter the motion of an almost barrierless DABCO are discussed here. In the part of experimental materials, we found many familiar compounds, such as 3,6-Dibromo-9H-carbazole(cas: 6825-20-3Formula: C12H7Br2N)
3,6-Dibromo-9H-carbazole(cas: 6825-20-3) is used as a pharmaceutical intermediate, and also an important intermediate of synthesizing optoelectronic materials. It has been used as a reagent in the synthesis of P7C3-A20 which is a potent neuroprotective agent.Formula: C12H7Br2N
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary