CAr鈥揌路路路O Hydrogen Bonds in Substituted Isobenzofuranone Derivatives: Geometric, Topological, and NMR Characterization

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• 作者：Mark V. Sigalov ; Evgeniya P. Doronina ; Valery F. Sidorkin
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：July 26, 2012
• 年：2012
• 卷：116
• 期：29
• 页码：7718-7725
• 全文大小：436K
• 年卷期：v.116,no.29(July 26, 2012)
• ISSN：1520-5215

文摘

Substituted isobenzofuranone derivatives 1a鈥?b>3a and bindone 4 are characterized by the presence of an intramolecular C_Ar鈥揌路路路O hydrogen bond in the crystal (X-ray), solution (¹H NMR and specific and nonspecific IEF-PCM solvation model combined with MP2 and B3LYP methods), and gas (MP2 and B3LYP) phases. According to geometric and AIM criteria, the C_Ar鈥揌路路路O interaction weakens in 1a鈥?b>3a (independent of substituent nature) and in 4 with the change in media in the following order: gas phase > CHCl₃ solution > DMSO solution > crystal. The maximum value of hydrogen bond energy is 4.6 kcal/mol for 1a鈥?b>3a and 5.6 kcal/mol for 4. Both in crystals and in solutions, hydrogen bond strength increases in the order 1a < 2a < 3a with the rising electronegativity of the ring substituents (H < OMe < Cl). The best method for calculating ¹H NMR chemical shifts (未^calcd 鈥?未^expl < 0.7 ppm) of hydrogen bonded and nonbonded protons in 1a鈥?b>3a and 1b鈥?b>3b (isomers without hydrogen bonds) is the GIAO method at the B3LYP level with the 6-31G** and 6-311G** basis sets. For the C鈥揌 moiety involved in the hydrogen bond, the increase of the spin鈥搒pin coupling constant ¹J(¹³C鈥?sup>1H) by about 7.5 Hz is in good agreement with calculations for C鈥揌 bond shortening and for blue shifts of C鈥揌 stretching vibrations (by 55鈥?5 cm^鈥?).