Nitroxides. LXX. Electron spin resonance study of cyclodextrin inclusion compounds

Martinie, J.; Michon, J.; Rassat, A.

doi:10.1021/ja00840a037

Cited by 130 publications

(57 citation statements)

References 12 publications

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“…Presumably the quite hydrophilic nature of the polymers prevents efficient binding of DTBN. Since the ESR spectral line shape will be mainly determined by the molecular motion of the DTBN probe and only to a small extent by that of the complexes [10,11], we conclude that the probe rotates more quickly in the SDS-polymer complexes than in unperturbed SDS micelles. Presumably, the headgroups of the SDS micelles sorbed on the polymer are less tightly packed and the spin probe resides in a less hydrophobic environment.…”

Section: Resultsmentioning

confidence: 80%

“…The modest decrease of AN (16.86 gauss in 70 mM SDS) reflects the reduced micropolarity at the binding sites in the micellar aggregate. The effective rotational correlation times [10,11] (re; in H20:1.7 x 10 -11 S, in 70 mM SDS: 1.5 x 10 -l~ s) were calculated from: rcho/,,2 /ho/,,: ] r,~ = 6.5 x 10 -~~ Wo Lk--I + \h+,l -2 where TWo is the peak-to-peak line width of the ESR midfield line (in gauss) and ho, h_l and h+ 1 are the peak-to-peak heights of the mid-, low-, and high-field lines, respectively. The assumptions involved in the use of this equation and the several factors which contribute to the observed line shape and line width of the paramagnetic probe have been discussed previously [10,11].…”

Section: Resultsmentioning

confidence: 99%

“…The effective rotational correlation times [10,11] (re; in H20:1.7 x 10 -11 S, in 70 mM SDS: 1.5 x 10 -l~ s) were calculated from: rcho/,,2 /ho/,,: ] r,~ = 6.5 x 10 -~~ Wo Lk--I + \h+,l -2 where TWo is the peak-to-peak line width of the ESR midfield line (in gauss) and ho, h_l and h+ 1 are the peak-to-peak heights of the mid-, low-, and high-field lines, respectively. The assumptions involved in the use of this equation and the several factors which contribute to the observed line shape and line width of the paramagnetic probe have been discussed previously [10,11]. At SDS concentrations above 20 mM a splitting of the high-field line into two signals is observed, indicating relatively slow exchange of DTBN between the aqueous and micellar phases in agreement with similar findings for cetyltrimethylammonium bromide micelles [12].…”

Section: Resultsmentioning

confidence: 99%

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Micelle-polymer complexes as studied by the ESR spin probe technique

Witte

Buwalda

Engberts

1987

Colloid & Polymer Sci

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Complexes between sodium dodecyl sulfate micelles and the water-soluble polymers poly(N-vinylpyrrolidone), poly(ethylene oxide) and a copolymer of poly(vinyl alcohol) and poly(vinyl acetate) have been studied in aqueous solution by the electron spin resonance (ESR) technique using di-tert-butyl nitroxide as a spin probe. The effective rotational correlation times reveal lowering of the critical micelle concentration and decreased headgroup packing in the micelle upon interaction with the polymers.

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Section: Resultsmentioning

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Micelle-polymer complexes as studied by the ESR spin probe technique

Witte

Buwalda

Engberts

1987

Colloid & Polymer Sci

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“…[4] An alternative way to perform host-guest studies with such insoluble hosts is to use appropriate organic paramagnetic guests, the behavior of which is easily detected by EPR spectroscopy in submillimolar concentrations. [11] This probe technique, which is not restricted to insoluble species, has been successfully applied to host-guest studies involving cyclodextrins, [12] calixarenes, [13] and more recently cucurbiturils. [14] The sensitivity of the paramagnetic probe to minor changes of the environment allows the inclusion process to be characterized and, in some cases, association and dissociation constants to be determined.…”

Section: Introductionmentioning

confidence: 99%

Inclusion of a Nitronyl Nitroxyl Radical and Its Hydrochloride in Cucurbit[8]uril

Peresypkina

Fedin

Maurel

et al. 2010

Chemistry A European J

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The recognition properties of cucurbit[8]uril (CB8) toward nitronyl nitroxide 2-(2-benzimidazolyl)-4,4,5,5-tetramethylimidazolidinyl-3-oxide-1-oxy (1) and its hydrochloride have been investigated. 1·HCl led to 1:1 inclusion complex [1·HCl@CB8], which was characterized both in solution and by single-crystal X-ray diffraction. In this compound only the tetramethylimidazolidinyl fragment is included in the host. The magnetic behavior of the complex corresponds to a Curie law with a large separation of the spin carriers in the solid. In contrast, an insoluble species exhibiting ferromagnetic behavior is formed when pure 1 reacts with acid-free CB8. The formula [(1)(2)@(CB8)(3)], in which two radical guests are arranged in such a way that the phenyl groups of the benzimidazolyl substituents are both stacked into one CB8 and the tetramethyl fragments are each capped by a terminal macrocycle, is proposed, in agreement with microanalysis, spectrophotometric, EPR, and magnetic measurements. According to McConnell's rules, the alternating spin densities within the stacked aromatic fragments result in a ferromagnetic interaction (J=+2.3 cm(-1), H=-2JS(1)S(2)) and a triplet ground spin state for the inclusion complex.

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“…At the fast motion region, all the utilized methods for calculation of rotational correlation times were based on the Kivelson line width theory [30]. However, asa result of approximations and also with the use of various parameters, different equations were given in the previous studies [31,32]. In this study, the equation given by Kuznetsov et al [33] was used T= where ABpp and /pp are the peak-to-peak line width and line height, respectively.…”

Section: Simulation Of Spectramentioning

confidence: 99%

Analysis of poly(ethylene oxide)-lithium/sodium dodecyl sulfate interactions by electron paramagnetic resonance simulation for 16-doxyl stearic acid

Demır

Paktaş

2005

Appl. Magn. Reson.

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The interaction of lithium dodecyl sulfate (LiDS) and sodium dodecyl sulfate (SDS) with poly(ethylene oxide) (PEO) has been studied with 16-doxyl stearic acid (16-DS) in aqueous solution by electron paramagnetic resonance (EPR). The rotational correlation times r c and nitrogen hyperfine eoupling constants A N versus the surfactant concentration with and without PEO have been calculated for different concentrations of 16-DS by our single-domain simulation program and EPRSIM program. Since the results of single-domain simulations were insufficient in pronounied changing the interval of re and A N values, spectra were also simulated with two and three domains to get better insight about domains. Better-fit results were found in these simulations. Data obtained from simulations revealed the effects of the polymer and surfactant counterion on the micelle formation and aggregation percentages. At about 8 mM SDS and about 12 mM LiDS concentrations, the presence of polymer provided more hydrophobic environment for I6-DS and this indicated that the loeation of the polymer was within the interface region. With the increase of the surfactant concentration, less hydrophobic environment was obtained for the nitroxide, which suggested a more open structure for the polymer-surfactant micelles.

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Nitroxides. LXX. Electron spin resonance study of cyclodextrin inclusion compounds

Cited by 130 publications

References 12 publications

Micelle-polymer complexes as studied by the ESR spin probe technique

Micelle-polymer complexes as studied by the ESR spin probe technique

Inclusion of a Nitronyl Nitroxyl Radical and Its Hydrochloride in Cucurbit[8]uril

Analysis of poly(ethylene oxide)-lithium/sodium dodecyl sulfate interactions by electron paramagnetic resonance simulation for 16-doxyl stearic acid

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