Dialkylaminobenzonitriles as Fluorescence Polarity Probes for Aqueous Solutions of Cyclodextrins

Cox, Graham; Hauptman, Paul J.; Turro, Nicholas J.

doi:10.1111/j.1751-1097.1984.tb03896.x

Cited by 115 publications

(52 citation statements)

References 30 publications

(10 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[137,138] For example, fluorescence intensity increases considerably (10-fold) if CyD is added to an aqueous solution of 1-anilinonaphthalene-8-sulfonate. Complex formation results in a higher fluorescence quantum yield, and the emission maximum is shifted towards shorter wavelengths.…”

Section: Fluorescence Spectroscopymentioning

confidence: 99%

A review on cyclodextrin encapsulation of essential oils and volatiles

Cabral-Marques

2010

Flavour & Fragrance J

578

360

View full text Add to dashboard Cite

Cyclodextrins (CyDs) are cyclic carbohydrates derived from starch. The parent CyDs contain six, seven and eight glucopyranose units and are referred as a-, b-and g-CyD, respectively. The most important property of the CyDs is the ability to establish specific interactions -molecular encapsulation -with various types of molecules through the formation of noncovalently bonded entities, either in the solid phase or in aqueous solution. These nano-encapsulating agents may form inclusion complexes with essential oils and volatiles, or their components, in order to improve their characteristics, such as transformation of liquid compounds into crystalline form; masking unpleasant smells and tastes of some compounds; improving the physical and/or chemical stability; and stabilizing volatile compounds by reducing or eliminating any losses through evaporation. Complexation has been used to avoid the destruction of certain flavours by processing or, on storage, allowing the use of minor amounts of flavours. The guest molecule is released in the warm moisture of the mouth. Examples are spices, essential oils of vegetable origin and plant flavours, chamomile oil and extract, eucalyptus oil, fennel oil, lemon oil, onion and garlic oil, camphor, menthol, thymol, etc. There are several methods for the preparation of inclusion complexes; kneading, co-precipitation, freeze-drying and spray-drying the most commonly used. Evidence for a guest inclusion into the apolar CyD cavity may be proved by various analytical techniques, including NMR spectroscopy, UV-visible absorption spectroscopy, optical rotatory dispersion and circular dichroism, fluorescence, infrared/FT-IR spectroscopy, thermo-analysis, TLC, mass spectromety, and powder X-ray diffractometry.

show abstract

Section: Fluorescence Spectroscopymentioning

confidence: 99%

A review on cyclodextrin encapsulation of essential oils and volatiles

Cabral-Marques

2010

Flavour & Fragrance J

578

360

View full text Add to dashboard Cite

show abstract

“…[27][28][29] However, most of these studies consider only the 1:1 complex formation. Few studies which take account of the higher order complexes have so far been made, such as the speculation of the formation of 1:2 complex by Al-Hassan 30 and Nag et al 31 and very recent reports by Panja and Chakravorti 32 and by Das.…”

Section: Resultsmentioning

confidence: 98%

Cavity Size Effect on the Excited State Dynamics of Methyl 4-(Dimethylamino)benzoate−Cyclodextrin Complexes

et al. 2004

View full text Add to dashboard Cite

The effect of cyclodextrin (CD) complexation on the fluorescence properties of methyl 4-(dimethylamino)-benzoate (MDMAB) was studied. The complex with R-, -, and γ-CDs exhibited twisted intramolecular charge transfer (TICT) fluorescence whereas only the emission from the locally excited state was observed in aqueous solution without CD. In the case of the R-CD complex, dual TICT emission was observed, a low-energy emission was centered at 520 nm, and a higher-energy emission was centered at 450 nm. The dependence of TICT emission intensity on pH and R-CD concentration suggested that the lower and higher energy emission can be attributed to the TICT states of MDMAB in the 1:1 and 1:2 MDMAB-R-CD complexes. On the other hand, only the formation of 1:1 complex was observed in the presence of -and γ-CDs. The cavity size effect on the fluorescence properties of MDMAB was further discussed on the basis of time-resolved laser spectroscopy.

show abstract

“…The exothermic peaks around 300°C for the β-cyclodextrin sample due to melting and thermal decomposition of the β-cyclodextrin itself [5]. Besides UV-vis spectra, Phase solubility study and Differential Scanning Calorimetry (DSC), there are other several techniques to characterize inclusion complex formation of cyclodextrin which are Infrared Spectroscopy [3], Vacuum Methods [33], X-ray Diffraction [36], Chromatography [37], Mass Spectrometry [3], Nuclear Magnetic Resonance Spectroscopy [38], Fluorescence Spectroscopy [39] and Optical Methods [40].…”

Section: Differential Scanning Calorimetry (Dsc)mentioning

confidence: 99%

Inclusion complex formation of cyclodextrin with its guest and their applications

Cheirsilp¹,

Rakmai²

2017

Biol Eng Med

View full text Add to dashboard Cite

Cyclodextrin (CD) are cyclic oligosaccharides consisting of glucopyranosyl units linked by α-(1,4) bonds. The widely used natural cyclodextrins are α-, β-and γ-cyclodextrin consisting of 6, 7 and 8 glucopyranose units, respectively. The cyclodextrin molecules have a unique structure with a hydrophobic cavity and a hydrophilic surface which can form inclusion complex with a wide variety of guests. The use of cyclodextrins and their derivatives for the encapsulation of bioactive compounds can protect the compounds from environmental conditions and improve the aqueous solubility for increasing their capacity to functionalize the products. In some cases, there is a need to enhance water solubility of β-cyclodextrin by adding the hydroxyalkyl groups on the β-cyclodextrin surface. This review aimed to summarize the method for inclusion complex formation of cyclodextrin with its guests and its applications. Table 1. The cyclodextrin molecules have a unique structure with a hydrophobic cavity and a hydrophilic surface in which a guest molecule can be entrapped. Cyclodextrin can form inclusion complex with a wide variety of solid, liquid and gaseous compounds. Complex formation is a dimensional, geometrically limited fit, between cyclodextrin cavity and the guest molecule [2].Generally, hydrophobic molecules have greater affinity for the cyclodextrin cavity when they are in water solution. Moreover, the encapsulation changes the physical and chemical properties of the guests, such as solubility and stability. Therefore, cyclodextrins are suitable for application in food and flavors, pharmaceutical products, cosmetic, agriculture and chemical industries. Cyclodextrins can link specifically to other cyclodextrins (covalent or noncovalent). Because of this property, cyclodextrins can be used as building blocks for the construction of supramolecular complexes. Building blocks which cannot be prepared by common methods can be applied, such as separation of complex mixtures of molecules and enantiomers [3]. Cyclodextrins are produced by reacting gelatinized starch with the enzyme cyclodextrin glucosyltransferase (CGTase) as a result of intramolecular transglycosylation reaction from degradation of starch. Inclusion complex formationCyclodextrins have an internal non-polar hole and hydroxyl groups placed on the surface, the inclusion of hydrophobic compounds takes place mainly by hydrophobic interactions between guest molecules and the walls of cyclodextrin cavity [5]. However, other forces, such as van der Walls and dipole-dipole interactions, may be involved in the binding of the guest. Despite the number of factors and different forces involved in the complexation with cyclodextrins, the production of complexes is a rather simple process. There are several methods to obtain cyclodextrin-guest complexes depending on the properties of the guest and the nature of the chosen cyclodextrin. Kneading methodKneading technique is suitable for poorly water-soluble guests, because the guest is dissolved slowly during the forma...

show abstract

Dialkylaminobenzonitriles as Fluorescence Polarity Probes for Aqueous Solutions of Cyclodextrins

Cited by 115 publications

References 30 publications

A review on cyclodextrin encapsulation of essential oils and volatiles

A review on cyclodextrin encapsulation of essential oils and volatiles

Cavity Size Effect on the Excited State Dynamics of Methyl 4-(Dimethylamino)benzoate−Cyclodextrin Complexes

Inclusion complex formation of cyclodextrin with its guest and their applications

Contact Info

Product

Resources

About