TY - JOUR

T1 - Azine Steric Hindrances Switch Halogen Bonding to N-Arylation upon Interplay with σ-Hole Donating Haloarenenitriles

AU - Baykov, Sergey V.

AU - Geyl, Kirill K.

AU - Ivanov, Daniil M.

AU - Gomila, Rosa M.

AU - Frontera, Antonio

AU - Kukushkin, Vadim Y.

N1 - Publisher Copyright: © 2021 Wiley-VCH GmbH

PY - 2021/6/1

Y1 - 2021/6/1

N2 - 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 N-arylation to give the corresponding azinium salts (characterized by 1H and 13C{H} NMR and high-resolution ESI-MS). In contrast, azines 4–9 with sterically hindered N atoms or bearing an electron-withdrawing substituent, form 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).

AB - 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 N-arylation to give the corresponding azinium salts (characterized by 1H and 13C{H} NMR and high-resolution ESI-MS). In contrast, azines 4–9 with sterically hindered N atoms or bearing an electron-withdrawing substituent, form 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).

KW - azines

KW - halogen bonding

KW - nitriles

KW - noncovalent interactions

KW - self-assembly

UR - http://www.scopus.com/inward/record.url?scp=85105173184&partnerID=8YFLogxK

U2 - 10.1002/asia.202100282

DO - 10.1002/asia.202100282

M3 - Article

C2 - 33844884

AN - SCOPUS:85105173184

VL - 16

SP - 1445

EP - 1455

JO - Chemistry - An Asian Journal

JF - Chemistry - An Asian Journal

SN - 1861-4728

IS - 11

ER -