Investigation of aromatic hydrocarbon inclusion into cyclodextrins by Raman spectroscopy and thermal analysis

Abstract

Among various cavitand molecules, cyclodextrins are extensively studied due to their ability to form host-guest complexes with small hydrophobic molecules. Aiming to explore cyclodextrin implementation on the scopes related to the environmental pollution monitoring or remediation, extensive studies for understanding the cyclodextrin-based host-guest complex formation with selected targeted substances are conducted. In this context, two polycyclic aromatic hydrocarbons, naphthalene and fluoranthene as well as toluene as a member of volatile organic compounds, were studied regarding their ability to encapsulate into cyclodextrin cavities. Synthesised complexes were examined by thermogravimetric analysis combined with Raman spectroscopy. The obtained results demonstrated that the size between targeted molecules and the cyclodextrin cavities strongly correlates with its ability to engage in complexation. Thus, this latter parameter plays an important role in the inclusion complex formation as well as in the strength of the interaction between the molecules.

Molecular Structure of Cefuroxime Axetil Complexes with α-, β-, γ-, and 2-Hydroxypropyl-β-Cyclodextrins: Molecular Simulations and Raman Spectroscopic and Imaging Studies

“…A much smaller contribution of OH groups in 2HP-β-CD+CA revealed by Raman intensity coefficient calculations results from the presence of fewer OH groups in the inner cavity area than in the case of other CDs and the substitution of the hydroxyl groups by propyl groups [ 16 ]. A high intensity band is clearly observed for the C–C–C bending at 496 cm −1 for α-CD+CA, and less intensity was recorded for β-CD+CA (497 cm −1 ) and 2HP-β-CD+CA; also, the bands at 1366 (α-CD+CA) and 1370 cm −1 (γ-CD+CA) attributed to C-C stretching exhibit a lower intensity as well as increased intensity of C–H stretching (1476 and 1472 cm −1 for α-CD+CA and γ-CD+CA, respectively) compared to the other modes, proving a similar type of interactions between CA [ 45 ] and α- and γ-CD. Moreover, an increased frequency of stretching vibrational modes of hydroxyl (O–H) groups in α-CD+CA and γ-CD+CA conjugates may imply the hydrogen bonds weakening in the host molecule and hence increasing the amphiphilic properties of CDs, especially in the case of γ-CD possessing the largest surface area corresponding to the guest–host interactions [ 72 ].…”

“…The most significant bands recorded in the Raman spectra of studied CA-CD complexes (assignments were made in accordance with refs [44][45][46][47]…”

High-Strength and High-Toughness Silk Fibroin Hydrogels: A Strategy Using Dynamic Host–Guest Interactions

“…Raman spectra confirmed the conjugation of β-CD onto the carboxylated SF molecule (Figure S1A, Supporting Information). Corresponding to the characteristic peaks of SF at 1421 and 1596 cm –1 , the peak of CD-SF at 479 cm –1 was assigned to the C–C–C bending of β-CD. , …”

“…Corresponding to the characteristic peaks of SF at 1421 and 1596 cm −1 , the peak of CD-SF at 479 cm −1 was assigned to the C−C−C bending of β-CD. 43,44 Chol-SF was prepared by the esterification reaction of Chol with the carboxylated SF. FTIR spectrum of Chol showed the characteristic peaks for C−H bond stretching at 2930 cm −1 Peaks at 702 and 1668 cm −1 , denoting deformations of the conjugated ring system and CC stretching vibration of Chol, respectively, indicated that Chol was conjugated onto the SF protein.…”

Highly sensitive detection of estradiol by a SERS sensor based on TiO2 covered with gold nanoparticles

“…The surface should provide a good enhancement over a large range of wavelengths, to detect molecules with various fingerprints, while it should also be easy to fabricate at reduced cost. In addition, the surface functionalization needs to guarantee the selection, detection and quantification of a target molecule, e.g., a biomarker [1][2][3] or a pollutant [4,5] dissolved in complex media such as blood, plasma, urine, or river and sea water. SERS is mainly based on an electromagnetic effect that originates from the excitation of plasmon resonances, in particular of localized surface plasmons (LSPs) in metallic nanoparticles (NPs).…”