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Abstract <p>2,4-Diamino-3,5,6-trifluorobenzonitrile makes cocrystals with macrocyclic 18-crown-6, 15-crown-5, and 12-crown-4 ethers of 4:3, 1:1, and 2:1 stoichiometries respectively. The inability to 1:1 cocrystallization with 18-crown-6 and a nonmonotonic change in the diamine fraction in the cocrystal when the macrocycle size changes distinguish it from a series of structurally similar polyfluoroarylenediamines. In all cocrystals synthesized the cyano group and the polyfluoroaromatic moiety participate in structure-forming interactions (N–H⋯N<sub>cyano</sub> H-bond, π⋯π and <i>p</i>⋯π contacts) supplementing the N–H⋯O<sub>cr</sub> H-bond with crown ether. Quantum chemical DFT computations of the molecular electrostatic potential, binding energies, and topological parameters of the electron density in dimers show a considerable contribution of interactions between aromatic coformer molecules to stabilization of the cocrystal structure. The key factor providing the 1:1 cocrystallization is π-stacking occurring in the cocrystal with 15-crown-5 and is violated when passing to 18-crown-6 due to an increase in the macrocycle size. The structural and quantum chemical analysis performed characterizes the hierarchy of supramolecular synthons as tools to design molecular crystals.</p>

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Competition Between Intermolecular Interactions in the Self-Assembly of Cocrystals of Polyfluorinated Arylenediamines with Crown Ethers: Effect of the Cyano Group

  • 期刊论文

  • 发表日期：

    2025年5月1日

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  • T. A. Vaganova,
  • Yu. V. Gatilov,
  • N. A. Kryuchkova,
  • D. P. Pishchur,
  • E. V. Malykhin

摘要

Abstract

2,4-Diamino-3,5,6-trifluorobenzonitrile makes cocrystals with macrocyclic 18-crown-6, 15-crown-5, and 12-crown-4 ethers of 4:3, 1:1, and 2:1 stoichiometries respectively. The inability to 1:1 cocrystallization with 18-crown-6 and a nonmonotonic change in the diamine fraction in the cocrystal when the macrocycle size changes distinguish it from a series of structurally similar polyfluoroarylenediamines. In all cocrystals synthesized the cyano group and the polyfluoroaromatic moiety participate in structure-forming interactions (N–H⋯Ncyano H-bond, π⋯π and p⋯π contacts) supplementing the N–H⋯Ocr H-bond with crown ether. Quantum chemical DFT computations of the molecular electrostatic potential, binding energies, and topological parameters of the electron density in dimers show a considerable contribution of interactions between aromatic coformer molecules to stabilization of the cocrystal structure. The key factor providing the 1:1 cocrystallization is π-stacking occurring in the cocrystal with 15-crown-5 and is violated when passing to 18-crown-6 due to an increase in the macrocycle size. The structural and quantum chemical analysis performed characterizes the hierarchy of supramolecular synthons as tools to design molecular crystals.