A molecular orbital study of cyclodextrin (cyclomalto-oligosaccharide) inclusion complexes. III, dipole moments of cyclodextrins in various types of inclusion complex

Sakurai, Minoru; Kitagawa, Masaki; Hoshi, Hajime; Inoue, Yoshio; Chûjô, Riichirǒ

doi:10.1016/0008-6215(90)84291-2

Cited by 70 publications

(35 citation statements)

References 51 publications

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“…In the present case, no hydrogen bonds were evidenced and, since there are no steric constraints to explain the difference between the A and B orientations in terms of stability, other forces must be considered. It is already known that cyclodextrin molecules have a rather high electric dipole moment; the correlation between this parameter and the complex stability by means of quantum-mechanical calculations has been previously reported [19–20]. The PP molecule has a permanent electric dipole, and the dipole–dipole interaction can make the difference between the A and B configurations.…”

Section: Resultsmentioning

confidence: 98%

Theoretical study on β-cyclodextrin inclusion complexes with propiconazole and protonated propiconazole

Fifere¹,

Marangoci²,

Maier³

et al. 2012

Beilstein J. Org. Chem.

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SummaryThe synthesis of the β-cyclodextrin/propiconazole nitrate inclusion complex and the advantages of the encapsulation of this drug were recently reported, but the experimental data only partially revealed the structure of the supramolecular complex due to the limitations in understanding the intermolecular association mechanism. The present work describes the equilibrium molecular geometries of β-cyclodextrin/propiconazole and β-cyclodextrin/protonated propiconazole, established by the AM1 and PM3 semi-empirical methods. The affinity between different parts of the guest molecule and the cyclodextrin cavity was studied considering that propiconazole possesses three residues able to be included into the host cavity through primary or secondary hydroxyl rims. The results have revealed that the most stable complex is formed when the azole residue of the propiconazole enters the cavity of the cyclodextrin through the narrow hydroxyl’s rim.

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Section: Resultsmentioning

confidence: 98%

Theoretical study on β-cyclodextrin inclusion complexes with propiconazole and protonated propiconazole

Fifere¹,

Marangoci²,

Maier³

et al. 2012

Beilstein J. Org. Chem.

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“…2, rests on the well known fact that CD molecules possess a dipole moment (see Figs. 2 and 4) [36]. For the peramino-CD used here this dipole moment is caused by the unequal number of different functionalities at the wide rim (14 OH-groups, see Fig.…”

Section: Article In Pressmentioning

confidence: 98%

Water-soluble, cyclodextrin-functionalized semiconductor nanocrystals: Preparation and pH-dependent aggregation and emission properties

Schärtl

Xie

Ren

et al. 2009

Journal of Luminescence

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“…These free-energy differences are a complex interplay of enthalpic and entropic contributions; however, the main driving force of complexation has not been identified yet. Possible effects are changes in Van der Waals forces [10] [13], hydrophobic interactions [14], and dipole -dipole alignment [10] [15], as well as electronic repulsion between frontier orbitals [16] (for an overview, see [12]). Liu and Guo [10] and Estrada et al [16] found the electronic effects to be more important in aCD inclusion complexes, whereas Cai et al [13] concluded that Van der Waals interactions are the most decisive ones.…”

mentioning

confidence: 99%

α‐Cyclodextrin Host–Guest Binding: A Computational Study of the Different Driving Forces

Riniker¹,

Daura²,

Gunsteren³

2010

Helvetica Chimica Acta

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Free-energy differences govern the equilibrium between bound and unbound states of a host and its guest molecules. The understanding of the underlying entropic and enthalpic contributions, and their complex interplay are crucial for the design of new drugs and inhibitors. In this study, molecular dynamics (MD) simulations were performed with inclusion complexes of a-cyclodextrin (aCD) and three monosubstituted benzene derivatives to investigate host -guest binding. aCD Complexes are an ideal model system, which is experimentally and computationally well-known. Thermodynamic integration (TI) simulations were carried out under various conditions for the free ligands in solution and bound to aCD. The two possible orientations of the ligand inside the cavity were investigated. Agreement with experimental data was only found for the more stable orientation, where the substituent resides inside the cavity. The better stability of this conformation results from stronger Van der Waals interactions and a favorable antiparallel host -guest dipole -dipole alignment. To estimate the entropic contributions, simulations were performed at three different temperatures (250, 300, and 350 K) and using positional restraints for the host. The system was found to be insensitive to both factors, due to the large and symmetric cavity of aCD, and the nondirectional nature of the host -guest interactions.Introduction. -a-Cyclodextrin (aCD) belongs to a family of cyclically closed oligosaccharides linked by a-bonds, where the number of glucose units ranges from six (aCD) to eight (gCD). The central cone-shaped cavity of cyclodextrins has hydrophobic character relative to bulk water, although actually semipolar [1] [2], while the rims of the cavity are hydrophilic due to the OH groups of glucose. The ability of aCD to bind small organic compounds in this cavity together with its small size renders it an ideal model for computational studies of host -guest binding [3 -5]. In addition, the system is well-studied experimentally [2] [6 -12]. Molecular dynamics (MD) simulations have reproduced the experimental relative free energies of binding [3]. These free-energy differences are a complex interplay of enthalpic and entropic contributions; however, the main driving force of complexation has not been identified yet. [16] found the electronic effects to be more important in aCD inclusion complexes, whereas Cai et al. [13] concluded that Van der Waals interactions are the most decisive ones. In addition, guest orientation in the cavity, steric effects, and the flexibility of the host may affect the equilibrium of the system. As the relative contributions of the

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A molecular orbital study of cyclodextrin (cyclomalto-oligosaccharide) inclusion complexes. III, dipole moments of cyclodextrins in various types of inclusion complex

Cited by 70 publications

References 51 publications

Theoretical study on β-cyclodextrin inclusion complexes with propiconazole and protonated propiconazole

Theoretical study on β-cyclodextrin inclusion complexes with propiconazole and protonated propiconazole

Water-soluble, cyclodextrin-functionalized semiconductor nanocrystals: Preparation and pH-dependent aggregation and emission properties

α‐Cyclodextrin Host–Guest Binding: A Computational Study of the Different Driving Forces

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