Synlett 2023; 34(10): 1113-1121
DOI: 10.1055/a-2071-4235
cluster
Dispersion Effects

Dispersion in Crystal Structures of 1-Chloro-3-aryl-5-trihalomethyl-1λ4,2,4,6-thiatriazines: Towards an Understanding of the Supramolecular Organization of Covalent Thiazyl Chlorides

Authors

  • Savini Suduweli Kondage

    a   Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Dr. W, Lethbridge, AB, Canada T1K 3M4, Canada
  • Tracey L. Roemmele

    a   Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Dr. W, Lethbridge, AB, Canada T1K 3M4, Canada
  • René T. Boeré

    a   Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Dr. W, Lethbridge, AB, Canada T1K 3M4, Canada
    b   The Canadian Centre for Research in Advanced Fluorine Technologies (C-CRAFT), University of Lethbridge, 4401 University Dr. W, Lethbridge, AB, Canada T1K 3M4, Canada

Research funding for this work was provided by ongoing Discovery Grants from the Natural Sciences and Engineering Research Council of Canada. The funding of the Bruker D8-Apex II diffractometer from the NSERC-C Research Tools and Instruments program, with a generous contribution from the University of Lethbridge, is gratefully acknowledged.


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Abstract

The syntheses of five new 1-chloro-3-aryl-5-trichloromethyl-1λ4,2,4,6-thiatriazines, aryl = 4-R-C6H4- (R = CH3O, CH3, H, Cl and CF3), are reported with full characterization. Single-crystal X-ray diffraction structure determinations on all, as well as the 5-CF3 analogue which also has R = CF3, with models produced by Hirshfeld atom refinement, produced high-accuracy structures. All six exemplars form lateral dimers with short contacts that define a centrosymmetric {δ+S···Nδ−}2 motif, with interaction distances from 3.0473(9) to 3.422(3) Å, which do not vary in an expected manner with R. Normal population analysis charges computed by B3LYP-D3/6-311++G(d,p) DFT methods show small variations, and entirely as expected from the inductive effects of R. Gas-phase minimization of the dimers with M06-2X/aug-cc-pVDZ or B3LYP-D3/6-311++G(d,p) methods, with full counterpoise correction, replicate the experimental geometries for the 5-CF3, the 5-CCl3/CH3OC6H4 and the 5-CCl3/CH3C6H4 experimental structures, but diverge for other CCl3 exemplars. Interaction energies are more than double those computed for [(HC)2N2S]2. Using a geometry-optimized model with H in place of CX3, the interaction energy reduces to a very realistic –22 to –24 kJ/mol for just the {δ+S···Nδ−}2 motif, suggesting that CX3 interactions contribute 21% (CF3) to 37% (CCl3) of the total.

Supporting Information



Publikationsverlauf

Eingereicht: 26. Februar 2023

Angenommen nach Revision: 12. April 2023

Accepted Manuscript online:
12. April 2023

Artikel online veröffentlicht:
23. Mai 2023

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