Inclusion Complexes of Ferrocenes and β-Cyclodextrins. Critical Appraisal of the Electrochemical Evaluation of Formation Constants

2000 ◽  
Vol 19 (14) ◽  
pp. 2791-2797 ◽  
Author(s):  
Domenico Osella ◽  
Andrea Carretta ◽  
Carlo Nervi ◽  
Mauro Ravera ◽  
Roberto Gobetto
Keyword(s):  
Inclusion Complexes ◽  
Critical Appraisal ◽  
Formation Constants ◽  
Electrochemical Evaluation

Studies of Chiral Modifiers on γ-Cyclodextrin-Pyrene Complexes Using Fluorescence Lifetime Measurements

1995 ◽  
Vol 49 (12) ◽  
pp. 1762-1765 ◽  
Author(s):  
A. Yvette Will ◽  
Jodi M. Schuette-Parsons ◽  
Rezik A. Agbaria ◽  
Isiah M. Warner
Keyword(s):  
Inclusion Complexes ◽  
Fluorescence Lifetime ◽  
Pure Water ◽  
Formation Constants ◽  
Chiral Alcohols ◽  
Lifetime Measurements

This work focuses on the inclusion complexes of γ-cyclodextrin and pyrene as indicated by fluorescence lifetime analyses and the influences of chiral alcohols and diols on these complexes. The 2-butanol participates in the γ-cyclodextrin-pyrene complexation and produces a longer lifetime of complexed pyrene than the value determined for the complex in pure water. The enantiomeric 1,3-butanediol also produces a longer lifetime of complexed pyrene. However, a decrease in this lifetime is observed in the presence of racemic 1,3-butanediol. This study also involves an estimation of formation constants for γ-cyclodextrin-pyrene complexes by use of the fluorescence lifetime measurements.

Electrochemical and Spectrophotometric Evaluation of the Formation Constants of the AA-βCD and DA-βCD Inclusion Complexes

2019 ◽  
Vol 15 (1) ◽  
pp. 507-516 ◽  
Author(s):  
Georgina Alarcón Ángeles ◽  
Silvia Corona- Avendaño ◽  
Manuel E. Palomar-Pardavé ◽  
Mario A. Romero-Romo ◽  
Alberto Rojas-Hernándéz ◽  
...  
Keyword(s):  
Inclusion Complexes ◽  
Formation Constants

Thermodynamic Parameters of the Inclusion Complexes of 2-Methylnaphthoate and α- and β-Cyclodextrins

1997 ◽  
Vol 51 (11) ◽  
pp. 1621-1627 ◽  
Author(s):  
Jose Manuel Madrid ◽  
Francisco Mendicuti
Keyword(s):  
Steady State ◽  
Thermodynamic Parameters ◽  
Inclusion Complexes ◽  
Emission Spectra ◽  
Formation Constants ◽  
Enthalpy Change ◽  
Dielectric Constants ◽  
High Enthalpy ◽  
Steady State Fluorescence ◽  
Good Probe

Steady-state fluorescence has been used to study the inclusion complexes of 2-methylnaphthoate (MN) with α- and β-cyclodextrins (CDs). Emission spectra of MN show two bands that are very sensitive to the CD concentration and temperature. The stoichiometry and formation constants of these complexes were investigated by obtaining the ratio of the two bands. Results showed identical stoichiometry (1:1) for both MN/α-CD and MN/β-CD complexes. However, the estimated formation constants were quite different. The thermodynamic parameters Δ H and Δ S were obtained from vant'Hoff plots. Results showed that MN/α-CD complexation is accompanied by an high enthalpy change, while MN/β-CD complexation is mainly en tropically favored. Anisotropy measurements were used to interpret the different signs of Δ S upon inclusion for both complexes. In addition, 2-methylnaphthoate seems to be a good probe for estimating microenvironmental polarity. Effective dielectric constants of inner α- and β-CD cavities were evaluated.

Stoichiometry and formation constants of pyrene inclusion complexes with .beta.- and .gamma.-cyclodextrin

1991 ◽  
Vol 95 (8) ◽  
pp. 3330-3334 ◽  
Author(s):  
A. Munoz de la Pena ◽  
T. Ndou ◽  
J. B. Zung ◽  
I. M. Warner
Keyword(s):  
Inclusion Complexes ◽  
Formation Constants ◽  
Gamma Cyclodextrin

The antimicrobial nalidixic acid as a probe for molecular recognition of α- and β-cyclodextrins

2002 ◽  
Vol 80 (10) ◽  
pp. 1313-1320 ◽  
Author(s):  
I S Shehatta ◽  
M S Ibrahim ◽  
M R Sultan
Keyword(s):  
Hydrogen Bond ◽  
Nalidixic Acid ◽  
Inclusion Complexes ◽  
Solution Structure ◽  
Formation Constants ◽  
Hydroxyl Group ◽  
Phase Solubility ◽  
Antibacterial Drug ◽  
Absorption Bands ◽  
Recognition Element

The inclusion of the antibacterial drug nalidixic acid (NAL) in α- and β-cyclodextrin (CD) cavities was studied using UV–vis absorption and voltammetric methods. It was corroborated that the UV absorption bands of NAL are intensified in the presence of α- and β-CDs. A pronounced decrease in the peak currents of NAL was also noticed upon the addition of α- and β-CDs. From the changes in the peak currents, it was concluded that NAL forms 1:1 inclusion complexes with the various hosts, which is also revealed in the phase solubility profile of the NAL–β-CD system, as a representative example. From voltammetric data, the logarithm of the binding constants were calculated to be 2.60 and 3.20 for α- and β-CDs, respectively. The magnitude of the formation constants, as well as the Gibbs free energies for NAL with α- and β-CDs, shows that NAL is bound more strongly to β-CD, with a more apolar cavity, than to α-CD. These observations suggest that hydrophobic interaction is the most important recognition element in the binding process. All orientations of entering NAL into the cavity have been considered herein, with the purpose of characterizing the inclusion complex of NAL with CD. Combining the experimental results and molecular modeling and energy calculations on the inclusion complexes yielded a more detailed picture of the solution structure of the complex formed between NAL and either α-CD or β-CD. It was inferred that the inclusion process can occur through the 2-methylpyridine side. An additional hydrogen bond was also found to be formed between the carboxyl group of NAL, which remains outside the β-CD cavity, and the secondary hydroxyl group of β-CD. This hydrogen bond should, therefore, be operating as an important second recognition element in the NAL–β-CD system. Key words: cyclodextrins, host–guest association, inclusion complexes, nalidixic acid, solubility, voltammetry.

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