Study of host-guess capacity of N-acylhydrazone-based macrocycles using NMR spectroscopy

Anca Gabriela Mirea (National Institute of Materials Physics, Romania)

Abstract: We present herein the synthesis of novel [2 + 2] and [3 + 3] N-acylhydrazone-based macrocycles using a pool of dialdehydes and dihydrazides. The macrocycles were used in various assays to investigate the hosting capacity of various guests using NMR.

  1. Amit Bhattacharya Avatar
    Amit Bhattacharya

    Hi Anca, interesting work! Could you please elaborate a bit more on how you inferred the triangular or tetragonal geometry using 2D NMR?

    1. Anca Gabriela Mirea Avatar
      Anca Gabriela Mirea

      Hy Amit! To elucidate the macrocyclic shape, we recorded 2D NMR (NOESY) indicating a triangular shape, according to the space interactions of protons within the molecule. The spectrum revealed NOE connectivity between NH and H (hydrazide moieties) protons, as well as CH=N and H (aldehyde moieties) protons. For more details you can read our article DOI: 10.1039/d4ta09035g.

      Thank you very much for your interest! I appreciate your question!

  2. Anca Gabriela Mirea Avatar
    Anca Gabriela Mirea

    Hy Amit! To elucidate the macrocyclic shape, we recorded 2D NMR (NOESY) indicating a triangular shape, according to the space interactions of protons within the molecule. The spectrum revealed NOE connectivity between NH and H (hydrazide moieties) protons, as well as CH=N and H (aldehyde moieties) protons. For more details you can read our article DOI: 10.1039/d4ta09035g.

    Thank you very much for your interest! I appreciate your question!

    1. Amit Bhattacharya Avatar
      Amit Bhattacharya

      Thanks Anca.

  3. Riley Hooper Avatar
    Riley Hooper

    Nice work Anca – why do you think the rectangular macrocycle readily took up F- and not Br-? What about Cl-? From your work, do you have any insights on what kind of synthetic considerations give rise to different macrocycle shapes?
    Thanks!

    1. Anca Gabriela Mirea Avatar
      Anca Gabriela Mirea

      Hy Riley! The interaction of the rectangular macrocycle with TBAF may either lead to deprotonation of the hydroxyl and amide groups or cause
      hydrogen bonding between the fluoride and the two groups.
      The shape of the macrocycle depends on the precursors used for the synthesis.

      Thank you very much for your interest! I appreciate your question!

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