Photophysical and photochemical properties of inclusion complexes of β-cyclodextrin with aminocoumarins

Asimov, M. M.; Рубинов, А. Н.

doi:10.1007/bf02606492

Cited by 6 publications

(5 citation statements)

References 12 publications

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“…[203][204][205][206][207][208][209][210][211][212][213] They have also been studied in CD cavities for different purposes. 66,[213][214][215][216][217][218][219][220][221][222] For coumarin 480 (C480) and coumarin 460 (C460) in aqueous solutions, the blue shift in the emission spectrum and the increase of the fluorescence lifetimes in the presence of γ-CD have been assigned to the formation of an inclusion complex with CD. [220][221][222] Molecular mechanics calculations for the C460:γ-CD complex suggest that the most stable inclusion complex has the carbonyl end of the guest near the narrower, primary OH end of the host and the amino end group of C460 near the secondary OH side of the cavity.…”

Section: Coumarins 460 and 480mentioning

confidence: 99%

“…Coumarins have been the subject of many steady-state and ultrafast studies. − They have also been studied in CD cavities for different purposes. ,− For coumarin 480 (C480) and coumarin 460 (C460) in aqueous solutions, the blue shift in the emission spectrum and the increase of the fluorescence lifetimes in the presence of γ-CD have been assigned to the formation of an inclusion complex with CD. − Molecular mechanics calculations for the C460:γ-CD complex suggest that the most stable inclusion complex has the carbonyl end of the guest near the narrower, primary OH end of the host and the amino end group of C460 near the secondary OH side of the cavity . The calculations also suggest the formation of a H-bond between the carbonyl group of the guest and two hydroxyl groups of the host.…”

Section: 2 Coumarins 460 and 480mentioning

confidence: 99%

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Ultrafast Guest Dynamics in Cyclodextrin Nanocavities

2004

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Section: Coumarins 460 and 480mentioning

confidence: 99%

Section: 2 Coumarins 460 and 480mentioning

confidence: 99%

Ultrafast Guest Dynamics in Cyclodextrin Nanocavities

2004

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“…A study on aminocoumarins [145] emphasizes the quality of the specific interaction with CDs to obtain a strongly enhanced fluorescence and stabilize the included coumarins. Their aim is to obtain better lasing conditions for these dyes.…”

Section: Enhancement Of the Fluorescence Of Guests Molecules In Cyclomentioning

confidence: 99%

Luminescence in organized media and supramolecular interactions:physicochemical aspects and applications

Lerner¹,

Martín²

2000

Analusis

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Introduction Molecular luminescence of analytes in organized media or in supramolecular complexes of cyclodextrinsThe photophysical and photochemical behaviour of molecules complexed to cyclodextrins (CD) is generally different from their behaviour in solution. The first observations in the field were qualitative and were related to the increased stabilisation of labile molecules, mostly drugs, against photodegradation when complexed to natural cyclodextrins [1]. Complexation by CD's was then the preferred subject for those involved in supramolecular chemistry and drug vectorisation techniques [2] as well as in separation techniques [3][4][5]. Stabilization of a molecule against photochemical degradation is still very important in the field of pharmaceutical sciences. A recent example is the stabilisation of promazine as an inclusion complex with β-cyclodextrin [6]. Other photochemists were attracted quite early to this field of research and initiated studies, which were mostly photophysical in nature [7,8]. The key observation was that the formation of supramolecular complexes of analytes with cyclodextrins (CDs) resulted in an increase of their fluorescence quantum yield or even in the appearance of room temperature phosphorescence (RTP) [9][10][11][12]. This enhancement has been used to increase the sensitivity and the selectivity in both luminescence and chromatographic techniques [13-15].We will not say more about RTP with CDs as the subject will be developed in another contribution in the same issue of this Journal. However RTP is also observed in the solubilization of analytes in micellar colloïdal solutions and this field will be reviewed hereunder.These properties have been used to develop analytical techniques, which combine the selectivity of complexation with an enhanced emission [16][17][18][19]. In this way an improvement in the detection limits is obtained in many separation techniques such as HPLC, capillary electrophoresis (CE) or planar chromatography. Furthermore these molecular interactions allow to reveal or to stabilize new molecular forms or to turn species which are normally non-emitting into luminescent ones. All these aspects are reviewed hereunder after a short summary on the nature of the intermolecular interactions, which lie at the heart of these effects. Nature of the interactions between an analyte and a CD or a micelleWithout going into a thorough analysis of the origin of the interactions which exist between molecules in dense media which concern us here, it seems useful to recall the most important factors which should be taken into account when any type of luminescence, fluorescence or phosphorescence is involved.

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“…It has been shown that CDs orientate their chemical and photochemical , reactivity. From a photophysical viewpoint, one important objective was to increase with CDs the solubility and stability of coumarins in water, in an attempt to use them as laser dyes. − CDs also proved to be useful in the spectrophotometric analysis of chiral coumarin-based pesticides. , Finally, the coumarin/CD system allowed the solvation dynamics in a restricted environment to be studied, mimicking the biological process that occurs within the cavity of proteins and lipid membranes …”

Section: Introductionmentioning

confidence: 99%

“…In the above-cited cases, there have been a number of observations that the spectroscopic properties of the dyes were modified in the presence of CDs. − , The effects observed varied strongly with the nature of the coumarin derivative used. Remarkable differences were also encountered for the binding constants.…”

Section: Introductionmentioning

confidence: 99%

Inclusion Complex of Fluorescent 4-Hydroxycoumarin Derivatives with Native β-Cyclodextrin: Enhanced Stabilization Induced by the Appended Substituent

and

Fery–Forgues

2001

J. Phys. Chem. B

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This work studies the interaction of substituted coumarins with β-cyclodextrin (β-CD). The role of the substituent in the 3 position was investigated. The guest molecules were two original 4-hydroxycoumarin derivatives, bearing an ethyl furoate (1) or a benzodioxanyl (2) substituent in the 3 position. Comparison was made with a nonsubstituted analogue (3). It must be noted that molecules 1 and 2 potentially offer very different complexation sites. Formation of the inclusion complex was checked by UV/vis absorption and fluorescence spectroscopy. A strong revival of the fluorescence intensity of 1 and 2 was observed in the presence of β-CD and partly attributed to the fact that the heterocyclic substituent was prevented from rotating freely. The 1:1 stoichiometry of the complex was established, and the values of the binding constants (7 × 10 2 and 3.4 × 10 2 M -1 for 1 and 2, respectively) were extracted from the spectrophotometric data. A much lower (8.1 × 10 1 M -1 ) binding constant was found for unsubstituted compound 3. The 1 H NMR study confirmed that the coumaryl ring system was engulfed in the cyclodextrin cavity. The proximal moiety of the heterocyclic substituent also interacted with the β-CD, whereas the rest protruded outside the cavity. This explains that the substituent controls the structure of the inclusion complex and contributes to its stabilization.

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Photophysical and photochemical properties of inclusion complexes of β-cyclodextrin with aminocoumarins

Cited by 6 publications

References 12 publications

Ultrafast Guest Dynamics in Cyclodextrin Nanocavities

Ultrafast Guest Dynamics in Cyclodextrin Nanocavities

Luminescence in organized media and supramolecular interactions:physicochemical aspects and applications

Inclusion Complex of Fluorescent 4-Hydroxycoumarin Derivatives with Native β-Cyclodextrin: Enhanced Stabilization Induced by the Appended Substituent

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