Competing Effects of Chlorination on the Strength of Te⋅⋅⋅O Chalcogen Bonds Select the Structure of Mixed Supramolecular Macrocyclic Aggregates of Iso‐Tellurazole N ‐Oxides Academic Article uri icon

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abstract

  • Chlorination of 3-methyl-5-phenyl-1,2-tellurazole-2-oxide yielded the λ4 Te dichloro derivative. Its crystal structure demonstrates that the heterocycle retains its ability to autoassociate by chalcogen bonding (ChB) forming macrocyclic tetramers. The corresponding Te⋅⋅⋅O ChB distances are 2.062 Å, the shortest observed to date in aggregates of this type. DFT-D3 calculations indicate that while the halogenated molecule is stronger as a ChB donor it also is a weaker ChB acceptor; the overall effect is that the ChBs in the chlorinated homotetramer are not significantly stronger. However, partial halogenation or scrambling selectively yield the 2 : 2 heterotetramer with alternating λ4 Te and λ2 Te centers, which calculations identified as the thermodynamically preferred arrangement.

authors

  • Vargas-baca, Ignacio
  • Ho, Peter C
  • Lomax, Justin
  • Tomassetti, Valerie
  • Britten, James F
  • Vargas‐Baca, Ignacio

publication date

  • July 26, 2021