S. Baykov, Kirill Geyl, D. Ivanov
Apr 12, 2021
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Influential Citations
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Journal
Chemistry, an Asian journal
Abstract
An interplay between 4-bromo- and 4-iodo-5-nitrophthalonitriles (XNPN, X = Br or I) and any one of the azines (pyridine 1 , 4-dimethylaminopyridine 2 , isoquinoline 3 , 4-cyanopyridine 4 , 2-methylpyridine 5 , 2-aminopyridine 6 , quinoline 7 , 1-methylisoquinoline 8 , and 2,2'-bipyridine 9 ) proceeds differently depending on steric and electronic effects of the heterocycles. Sterically unhindered azines 1 - 3 underwent the N -arylation to give the corresponding azinium salts (characterized by 1 H and 13 C{H} NMR and high-resolution ESI-MS). In contrast, azines 4 - 9 with sterically hindered N atoms or bearing an electron-withdrawing substituent, are formed stable co-crystals with XNPN, where two interacting molecules are bound by halogen bonding. In all obtained co-crystals, X ··· N structure-directed halogen bonds were recognized and theoretically evaluated including DFT calculations (PBE0-D3/def2-TZVP level of theory), QTAIM analysis, molecular electrostatic potential surfaces, and noncovalent interaction plot index. Estimated energies of halogen bonding vary from -7.6 kcal/mol (for 6· INPN) to -11.4 kcal/mol ( 5· INPN).