Thermodynamic Study of Chlorobenzonitrile Isomers: A Survey on the Polymorphism, Pseudosymmetry, and the Chloro路路路Cyano Interaction

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• 作者：In锚s M. Rocha ; Tiago L. P. Galv茫o ; Maria D. M. C. Ribeiro da Silva ; Manuel A. V. Ribeiro da Silva
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：February 27, 2014
• 年：2014
• 卷：118
• 期：8
• 页码：1502-1510
• 全文大小：363K
• 年卷期：v.118,no.8(February 27, 2014)
• ISSN：1520-5215

文摘

The relationships among structural and thermodynamic properties of 2-, 3-, and 4-chlorobenzonitrile were investigated, in the present work, using several experimental techniques (Knudsen effusion, differential scanning calorimetry, and combustion calorimetry) and computational studies. The CN路路路Cl intermolecular interactions are weaker in 2-chlorobenzonitrile, reflecting a lower enthalpy of sublimation. The two polymorphic forms of 4-chlorobenzonitrile were observed by differential scanning calorimetry and interpreted in terms of the strength of CN路路路Cl intermolecular interactions. The entropic differentiation due to the pseudosymmetry observed in the crystalline packing of 2-chlorobenzonitrile was evaluated. Using adequate working reactions and the respective standard molar enthalpies of formation, in the gaseous phase, the halogen鈥揷yano intramolecular interaction was also evaluated. The theoretically estimated gas-phase enthalpies of formation were calculated using high-level ab initio molecular orbital calculations at the G3MP2B3 and MP2/cc-pVTZ levels of theory. The computed values support very well the experimental results obtained in this work.