The physical properties and unusual pyrolysis behaviour of a supramolecular complex of β-cyclodextrin and potassium ferrioxalate

Abstract

The thermal pyrolysis behaviour of a complex of β-cyclodextrin (CD) and potassium ferrioxalate (PF) was analyzed using gas chromatography coupled to time-of-flight mass spectrometry. Two rare inorganic ions: CO(2)(2+) and O(4)(+), neither of which was found in the cases of free β-CD and PF, were synchronously observed during the decomposition of the complex. Our observations led to proposed formation mechanisms of the ions, in which the structural transformation of a metastable intermediate ion (C(2)H(4)O(3)(+)) was employed to qualitatively explain our data. Besides this, the formation, structure and magnetic properties of the complex were evaluated carefully. First, XPS analysis indicates a decrease of electron densities of Fe(III) ions in the presence of β-CD. We think that this is due to an effect of the noncovalent complexation between PF and β-CD. This gives an indication on the effect of second sphere coordination of β-CD on the electronic structure of the Fe(III) in the first coordination sphere. Second, structural changes in stacking modes and morphologies provide further support for the noncovalent complexation. For example, the surface feature of the complex gives us an impression that both β-CD and PF are evenly dispersed with each other. Also, the complex presents a uniform sponge-like porous nanostructure with diameters of less than 50 nm. This seems to be an important reason for those changes that occurred in the thermal analysis. Finally, the result of magnetic experiments implies that the coordination compound PF upon complexation with β-CD will experience a gradual decrease in magnetization with the increase of magnetic fields. These observations have significant implications for a better understanding of the importance of the construction and deconstruction of a second sphere coordination in modifying the physical properties of an σ-coordination compound.

Controlled Morphological Transformation, Photocatalytic Properties, and Electrocatalytic OER Performance of Fe-MOF Nanopolyhedra

“…We have not observed any bump in these curves, implying that there is no magnetic phase transition. Moreover, the M values are always positive, which is a typical feature of paramagnetic materials …”

“…We have not observed any bump in these curves, implying that there is no magnetic phase transition. Moreover, the M values are always positive, which is a typical feature of paramagnetic materials 42. Figure8Bdisplays the relationship between M and H at 5 and 300 K. At 5 K, the M values of all the samples increase rapidly at the relatively low field (0∼25 kOe).…”

“…Moreover, the M values are always positive, which is a typical feature of paramagnetic materials. 42 Figure 8B displays the relationship between M and H at 5 and 300 K. At 5 K, the M values of all the samples increase rapidly at the relatively low field (0∼25 kOe). However, at relatively high fields (25∼60 kOe), these values of M increase slowly and tend to be close to saturation at 60 kOe.…”

Low-Temperature Carbonization and More Effective Degradation of Carbohydrates Induced by Ferric Trichloride

“…FE-SEM images of the figure illustrate a change in surface features of the materials. The single crystal of the β-CD is shaped like a hexagonal prism, − roughly 1–2 μm in side length and 1–3 μm in height. However, the particles of M 1 look like a thin pancake with a thickness of about 100 nm, while the crystals of M 2 and M 3 have the shape of an irregular sand grain.…”

Increased Water Solubility of Molybdenum Trioxide Induced by <em>&beta;</em>-Cyclodextrin

“…Additionally, TG analyses (see Fig. S9) show that the β-CD molecule in BGP presents a much lower decomposition temperature (560 K) in comparison with free β-CD (587 K) 37 and especially with the mixture (591 K). This implies that the molecule-ion interaction seriously impairs the thermal stability of β-CD.…”