Structure confirmation and thermal kinetics of the inclusion of cis-jasmone in β-cyclodextrin

In this study, inclusion complex of cis-jasmone in β-CD (β-CD-CJ) was synthesized to improve cis-jasmone stability. The structure and thermal kinetics of the inclusion complex was investigated by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). DSC studies showed that the stability of cis-jasmone after β-cyclodextrin encapsulation was improved. The dissociation kinetics of β-CD-CJ at different heating rates was studied by TG, and the activation energy E of β-CD-CJ thermal decomposition kinetic parameters was defined by Flynn–Wall–Ozawa method. The results showed that the average activation energy E was 121.16 kJ mol⁻¹.

In this study, inclusion complex of cis-jasmone in β-CD (β-CD-CJ) was synthesized to improve cis-jasmone stability.

Electrospray ionization mass spectrometry studies of cyclodextrin-carboxylate ion inclusion complexes

Aqueous solutions containing simple model aliphatic and alicyclic carboxylic acids (surrogates 1-4) were studied using negative ion electrospray mass spectrometry (ESI-MS) in the presence and absence of alpha-, beta-, and gamma-cyclodextrin. Molecular ions were detected corresponding to the parent carboxylic acids and complexed forms of the carboxylic acids; the latter corresponding to non-covalent inclusion complexes formed between carboxylic acid and cyclodextrin compounds (e.g., beta-CD, alpha-CD, and gamma-CD). The formation of 1:1 non-covalent inclusion cyclodextrin-carboxylic complexes and non-inclusion forms of the cellobiose-carboxylic acid compounds was also observed.Aqueous solutions of Syncrude-derived mixtures of aliphatic and alicyclic carboxylic acids (i.e. naphthenic acids; NAs) were similarly studied using ESI-MS, as outlined above. Molecular ions corresponding to the formation of CD-NAs inclusion complexes were observed whereas 1:1 non-inclusion forms of the cellobiose-NAs complexes were not detected. The ESI-MS results provide evidence for some measure of inclusion selectivity according to the 'size-fit' of the host and guest molecules (according to carbon number) and the hydrogen deficiency (z-series) of the naphthenic acid compounds. The relative abundances of the molecular ions of the CD-carboxylate anion adducts provide strong support for differing complex stability in aqueous solution. In general, the 1:1 complex stability according to hydrogen deficiency (z-series) of naphthenic acids may be attributed to the nature of the cavity size of the cyclodextrin host compounds and the relative lipophilicity of the guest.