Charge Density Analysis and Topological Properties of Hal3-Synthons and Their Comparison with Competing Hydrogen Bonds

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• 作者：Mariya E. Brezgunova ; Emmanuel Aubert ; Slimane Dahaoui ; Pierre Fertey ; S茅bastien Leb猫gue ; Christian Jelsch ; J谩nos G. 脕ngy谩n ; Enrique Espinosa
• 刊名：Crystal Growth & Design
• 出版年：2012
• 出版时间：November 7, 2012
• 年：2012
• 卷：12
• 期：11
• 页码：5373-5386
• 全文大小：865K
• 年卷期：v.12,no.11(November 7, 2012)
• ISSN：1528-7505

文摘

Trimers based on intermolecular halogen-bonding interactions (Hal₃-synthons) have been studied in hexachlorobenzene, hexabromobenzene, pentachlorophenol, and pentabromophenol. Attention is paid to the comparison of Cl₃- and Br₃-synthons and to their competition with hydrogen bonds (HBs), based on the experimental and theoretical charge density analyses in crystal and gas phases. The main differences between Cl₃- and Br₃-synthons are established coming from the particular structure of the valence shell charge concentration region in Cl and Br atoms. Electrophilic鈥搉ucleophilic interactions take place within the intermolecular regions of Hal₃-synthons by putting face-to-face charge depletion (CD) and charge concentration (CC) regions belonging to the valence shell of the halogen atoms. The electrostatic interaction follows the electrophilic and nucleophilic power of these regions and is monitored by the negative Laplacian values normalized to charge density unit (L/蟻) at the corresponding topological critical points (CPs) of the L(r) = 鈭?img src="/appl/literatum/publisher/achs/journals/entities/2207.gif" alt="" class="entityA" align="absbottom" />²蟻(r) function. According to the topological and energetic properties at CPs of 蟻(r) and L(r), it is observed that Hal₃-synthons can successfully compete with intermolecular HBs in the analyzed structures. On the basis of the estimated interaction energy and the electrostatic descriptor 螖(L/蟻) = (L/蟻)_CC 鈥?(L/蟻)_CD, we conclude that a strong dispersion contribution assists Hal3-synthons in this competition.