Experimental and Theoretical Charge Density Studies of 8-Hydroxyquinoline Cocrystallized with Salicylic Acid

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• 作者：Thanh Ha Nguyen ; Paul W. Groundwater ; James A. Platts ; David E. Hibbs
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：April 5, 2012
• 年：2012
• 卷：116
• 期：13
• 页码：3420-3427
• 全文大小：481K
• 年卷期：v.116,no.13(April 5, 2012)
• ISSN：1520-5215

文摘

The experimental electron density distribution (EDD) in 8-hydroxyquinoline cocrystallized with salicylic acid, 1, has been determined from a multipole refinement of high-resolution X-ray diffraction data collected at 100 K. The experimental EDD is compared with theoretical densities resulting from high-level ab initio and BHandH calculations using Atoms in Molecules theory. 1 crystallizes in the triclinic crystal system, and the asymmetric unit consists of a neutral salicylic acid molecule, a salicylate anion, and an 8-hydroxyquinolinium cation exhibiting a number of inter- and intramolecular hydrogen bonds and 蟺鈥撓€ interactions. Topological analysis reveals that 蟺鈥撓€ interactions are of the 鈥渃losed-shell鈥?type, characterized by rather low and flat charge density. In general, the agreement of the topological values (蟻_bcp and ²蟻_bcp) between experiment and theory is good, with mean differences of 0.010 e 脜^鈥? and 0.036 e 脜^鈥?, respectively. The energetics of the 蟺鈥撓€ interactions have been estimated, and excellent agreement is observed between the relative energy and the strength of 蟺-stacking derived from the Espinosa approach, with an average difference of only 4.4 kJ mol^鈥?.