Dynamics of Hydrogen Bonding in Three‐Component Nanorotors. Issue 62 (6th October 2020)

• Record Type: Journal Article
• Authors: Biswas, Pronay Kumar; Goswami, Abir; Saha, Suchismita; Schmittel, Michael
• Is Part Of: Chemistry. Volume 26:Issue 62(2020)
• Page Start: 14095
• Page End: 14099
• Publication Date: 2020-10-06
• Subjects: hydrogen bonding -- multicomponent assembly -- rotational dynamics -- self-assembly -- self-sorting; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202002877
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The dynamics of hydrogen bonding do not only play an important role in many biochemical processes but also in Nature's multicomponent machines. Here, a three‐component nanorotor is presented where both the self‐assembly and rotational dynamics are guided by hydrogen bonding. In the rate‐limiting step of the rotational exchange, two phenolic O‐H–N, N(phenanthroline) hydrogen bonds are cleaved, a process that was followed by variable‐temperature 1 H NMR spectroscopy. Activation data (Δ G ≠ 298 =46.7 kJ mol −1 at 298 K, Δ H ≠ =55.3 kJ mol −1, and Δ S ≠ =28.8 J mol −1 K −1 ) were determined, furnishing a rotational exchange frequency of k 298 =40.0 kHz. Fully reversible disassembly/assembly of the nanorotor was achieved by addition of 5.0 equivalents of trifluoroacetic acid (TFA)/1, 8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) over three cycles. Abstract : In a spin : Two three‐component nanorotors are presented where both the reversible formation and rotational dynamics decisively depend on the proper geometric fit of intra‐supramolecular hydrogen bonding. In the rate‐limiting step of the rotational exchange, two phenolic O‐H–N, N(phenanthroline) hydrogen bonds were cleaved, a process that was investigated by variable‐temperature (VT) 1 H NMR spectroscopy.