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

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
,
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
› Institutsangaben

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.

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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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