Complexes of О±-, ОІ-, and Оі-Cyclodextrins with Nitrophenols: A Theoretical Study of the Structure and Energy
S.S. Kiselev, Yu.A. Borisov
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, Russia
Keywords: циклодекстрины, нитрофенолы, комплексы внедрения, DFT, cyclodextrins, nitrophenols, intercalation complexes, DFT
Abstract
Detailed quantum mechanical calculations of the interaction of cyclodextrin (α-, β-, and γ-CD) with 4-nitrophenol (I), 4-nitro-2,6-dimethylphenol (II), 4-nitro-3,5-dimethylphenol (III), and their anions (IV-VI) with the formation of intercalation complexes are carried out for the first time. The calculations of the compounds are performed within the density functional theory by the hybrid Becke-Lee-Yang-Parr (B3LYP) method with LanL2DZ basis sets. For the α-CD+III and α-CD+VI complexes it is shown that a nitrophenol molecule of III and a nitrophenolate anion of VI are not contained in the α-CD torus, which agrees with the experimental equilibrium constants. It is found that the calculated equilibrium constants of the formation of guest-host complexes with phenolate anions are much larger than those of neutral molecules. The most stable CD complexes with nitrophenols and their anions should be expected for γ-CD. The β-CD complexes when the guest enters into the host cavity are formed only with compounds I, V, and VI.
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