Inclusion compounds of phenol derivatives with cyclodextrins: a combined spectroscopic and thermal analysis

Abstract

Inclusion compounds involving α-, β-and γ -cyclodextrins (α-, β-and γ CD) and phenol derivatives, namely 3-methoxyphenol (3MeOPh), 2-methoxyphenol (2MeOPh) and 3-methylphenol (3MePh), were investigated and characterized by combining Raman spectroscopy, ab initio calculations, DSC and TG analysis. The effects of the inclusion process on the guest molecules and on the hydrogen bond interactions of the guests were studied by monitoring sensitive modes, such as C-C and C-H ring stretching modes. Moreover, the combined use of the data available from Raman spectra, computational methods and the known x-ray structures of similar compounds, allowed the proposal of most probable structures for the αCD inclusion compounds. Both inclusion compounds of meta-substituted guests in αCD present unusual 1 : 2 or 2 : 3 stoichiometries. The Raman spectra of these inclusion compounds reveal the split of several modes, spread over the entire spectral range, indicating the presence of guest molecules inside and outside the CD cavity.

Enhanced Antiproliferative Activity of the New Anticancer Candidate LPSF/AC04 in Cyclodextrin Inclusion Complexes Encapsulated into Liposomes

“…4a, b) and 2,800-3,200 cm −1 region (Fig. 4c, d) (31). The combined results of Raman and FTIR confirm the inclusion compound and also that LPSF/AC04:HP-β-CyD is relatively more stable than the LPSF/AC04:HP-γ-CyD inclusion complex, hence the choice of the LPSF/AC04:HP-β-CyD complex for further investigation.…”

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

“…Indeed, since this temperature is intermediate between the ones observed for individual CD and for individual NAP, we assume that it should be assigned to third process corresponding to the decomposition of NAP included inside the CD. Similar shift in guest decomposition temperature have been already observed by other groups (Nolasco et al 2009;Sardo et al 2009). The shift in decomposition temperature between free NAP and the one embedded into host indicates that the host-guest interaction protects the pollutant molecules from early volatilization.…”

“…Following the procedure described in literature (Sardo et al 2009), based on co-precipitation method, saturated aqueous solutions of αCD, βCD and γCD were mixed with aromatic compounds (TOL, NAP and FL) dissolved in ethanol at the concentration of 50 mM. The addition of the pollutant solutions into CDs, were made drop-wise using strong agitation at ambient temperature.…”

“…Generally, an increasing number of guest molecules involved in the complex was expected (with an increasing cavity size (αCD < βCD < γCD)). The γCD cavity is the wider and may be able to accommodate two guest molecules (Sardo et al 2009). On the contrary, αCD is the smaller host so its cavity is not large enough to accommodate one aromatic guest.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part IV

“…Nolasco et al 192 have carried out studies in the solid state with thermogravimetry and Raman spectroscopy to propose the host–guest structure of the inclusion complexes of trans ‐cinnamic acid and a number of its hydroxyl derivatives with α‐, β‐, and γ‐cyclodextrin molecules. In a related study involving inclusion complexes, Sardo et al 193 studied the complexes of 3‐methoxyphenol (3MeOPh), 2‐methoxyphenol (2MeOPh), and 3‐methylphenol (3MePh) with α‐, β‐, and γ‐cyclodextrins using Raman spectroscopy, ab initio calculations, differential scanning colorimetry (DSC), and thermogravimetry (TG) analysis. Wermelinger and Spolenak194 investigated the microstructure changes upon indentation of single‐crystalline (100)‐oriented silicon by transmission electron microscopy and Raman microscopy.…”