NYUAD Associate Professor of Chemistry Pance Naumov's collaborative work with Colin-Molina, Garcia-Garibay and others was published in Elsevier's Matter in an article entitled, "Thermosalient Amphidynamic Molecular Machines: Motion at the Molecular and Macroscopic Scales" and spotlighted in Cell Press' Trends in Chemistry in an article entitled, "Amphidynamic Crystals Key to Artificial Molecular Machines" by Indranil Roy and J. Frasier Stoddart.
Read the original research article here:
Read the spotlight here:
Summary: The supramolecular amphidynamic rotor 1, composed of two carbazole molecules acting as the stator and a DABCO rotator, exhibits remarkable thermosalience above 316 K. During this process, the crystals spontaneously transduce collective molecular displacements into macroscopic movement due to a phase transition, which is described by single-crystal X-ray analyses from 100 K to 320 K. The fast rotation in the low-temperature phase (I) occurs with a low activation energy Ea(I) ≈ 2.6 kcal mol−1 and a pre-exponential factor A(I) ≈ 1012 s−1. Increased symmetry of the cavity in the high-temperature phase (II) resulted in slower dynamics, regardless of a smaller rotational barrier, Ea(II) ≈ 0.5 kcal mol−1, due to the large reduction in the pre-exponential factor to A(II) ≈ 107 s−1. These results demonstrate that a relatively small distortion of lattice framework leads to drastic dynamic effects at both molecular and macroscopic scales, helping us to understand responsive crystalline materials.