Search

Density functional theory method and B3LYP/6‐311++G(d,p) level of theory were used to determine the acidity of α‐carbon in the hydroxyl derivatives of beta diketones in the gas phase. An investigation of acidity strength in the gas phase indicates that α‐carbon of hydroxyl derivatives of beta diketones become stronger acids than the α‐carbon of beta diketone itself as their conjugate bases gain more stability via both enolate and hydrogen bond formation. Natural bond orbital and quantum theory of atoms in molecules analyses also confirm the role of hydrogen bond interactions on increasing the acidity of α‐carbon of hydroxyl derivatives of beta diketones. [ABSTRACT FROM AUTHOR]

In this study, the effects of the remote intramolecular hydrogen bonding on the acidity of hydroxy‐1,4‐benzoquinone derivatives have been investigated ab initio by employing density functional theory (DFT) methods. The computational studies were performed for both gas and solution (H2O, DMSO, and MeCN solutions) phases. Our results indicated that remote hydrogen bonding could play an important role in increasing the acidity of hydroxy‐1,4‐benzoquinone. Noncovalent interaction reduced density gradient (NCI‐RDG) methods were used to visualize the attractive and repulsive interactions in the studied acids and their conjugate bases. Natural bond orbital (NBO) analysis was performed to confirm intramolecular hydrogen bonding effect on acidity. Quantum theory of atoms in molecules (QTAIM) was also used to study the nature of hydrogen bonds. QTAIM results showed that the intramolecular hydrogen bonds in these structures are electrostatic (closed‐shell) interactions in nature. In this study, the effects of the remote intramolecular hydrogen bonding on the acidity of hydroxy‐1,4‐benzoquinone derivatives are explored by using ab initio and density functional theory (DFT) calculations. It was found that remote hydrogen bonding could play a surprisingly role in increasing the acidity of hydroxy‐1,4‐benzoquinone. [ABSTRACT FROM AUTHOR]