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Abstract  

Tetracyanocomplex clathrates and their changes caused by heating were studied. The intermediates formed were characterized by IR and UV-VIS spectroscopy. Elemental analysis and XRD patterns were also used. For the visualisation of changes occurring on the surface and the distribution of metallic elements therein were studied by electron microscopy and EDX. The extent of the non-stoichiometric changes introduced by the topochemical course of the degradation reactions was correlated with the measured electrical values.

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Journal of Thermal Analysis and Calorimetry
Authors:
D. V. Pinakov
,
V. A. Logvinenko
,
G. N. Chekhova
, and
Yu. V. Shubin

clathrate systems: from 9.47 to 9.02 Å for the first stage FGICs (FGIC-1) with acetonitrile [ 1 ], from 10.03 to 9.61 Å for chloroform FGICs [ 2 ], from 10.28 to 9.80 Å with dichloroethane [ 3 ], from 9.82 to 9.32 Å for inclusion compounds with methylene

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Abstract  

Nifedipine complexes with β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD), 2-hydroxypropyl-β-cyclodextrin (2HP-β-CD), randomly methylated-β-cyclodextrin (RM-β-CD) and heptakis(2,6-O-dimethyl)-β-cyclodextrin (DM-β-CD) have been prepared by both kneading and heating methods and their behaviour studied by differential scanning calorimetry (DSC), diffuse reflectance mid-infrared spectroscopy (FTIR) and X-ray diffractometry (XRD). DSC revealed the nifedipine melting endotherm with onset at approximately 171°C for the kneaded mixtures with β-CD, γ-CD and 2HP-β-CD, thus confirming the presence of nifedipine in the crystalline state, while some decrease in crystallinity was observed in the DM-β-CD kneaded mixture. With RM-β-CD, however, broadening and shifting of the nifedipine endotherm and reduction in its intensity suggested that the kneading could have produced an amorphous inclusion complex. These differing extents of interaction of nifedipine with the cyclodextrins were confirmed by FTIR and XRD studies.

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Abstract  

The decomposition of series of supramolecular compounds, namely inclusion compounds, was studied by means of different thermoanalytical methods, i.e., traditional thermogravimetry, quasi-equilibrium thermogravimetry, and thermomechanical analysis. The series of compounds included the intercalates on the base of fluorinated graphite C2F, the clathrates on the base of carbamide and on the base of coordination compounds and microporous inclusion compounds on the base of coordination compounds. Kinetic parameters of decomposition processes were estimated within the approaches of the non-isothermal kinetics (“model-free” kinetics, linear and non-linear regression methods for the topochemical equation detection). The kinetic stability of the inclusion compounds under heating, the flexibility of the matrix structure, and the thermodynamic stability of the intermediate phases are discussed.

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Journal of Thermal Analysis and Calorimetry
Authors:
D. Pinakov
,
V. Logvinenko
,
Yu. Shubin
, and
G. Chekhova

Abstract  

Inclusion compounds (intercalates) of fluorinated graphite matrix with methylene dichloride (C2F x Br z ·yCH2Cl2, x = 0.49, 0.69, 0.87, 0.92, z ≈ 0.01) were synthesized by guest substitution from acetonitrile to methylene dichloride. The kinetics of the thermal decomposition (the first stage of filling → the second stage of filling) was studied under isothermal conditions at 291–303 K. The relationship between the structure of host matrices with thermal properties and kinetic parameters of inclusion compounds is discussed.

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Differential scanning calorimetry DSC has been applied to the analysis of drugcyclodextrin binary systems in order to gain experimental evidence of the interaction and determine the stoichiometry of the inclusion compound. Two model systems, paracetamolbetacyclodextrin and vinburnineg-ammacyclodextrin were tested through the comparison of thermal behaviors of interacted and non-interacted mixtures containing excess drug. DSC allowed a confirmation of both interaction and stoichiometry of the inclusion compounds.

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Inclusion by a fluorenyl diol host with substituted pyridines

Structures, selectivity and kinetics of desorption

Journal of Thermal Analysis and Calorimetry
Authors:
L. Nassimbeni
,
G. Ramon
, and
E. Weber

Abstract  

The structures of the inclusion compounds formed by the host 9,9’-(ethyne-1,2-diyl)bis(fluoren-9-01) with pyridine and picolines are similar and display tubular topology. The host discriminates poorly between these guests. The kinetics of desorption of the pyridine compound is governed by the Avrami-Erofe’ev equation A2, with an activation energy of 111(7) kJ mol−1.

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Abstract  

An earlier study of the interaction between solid urea and n-octane vapour in the presence of noncomplex-forming hydrocarbons by means of a vacuum microbalance technique revealed the oscillatory nature of urea-octane inclusion compound (complex) formation: process damping, occurrence in the reverse direction and repeated renewal without attainment of the complete saturation of the urea with octane. The phenomenon is interpreted on the basis of the recently discovered oscillatory adsorption, regarded as the surface competition between the spottily adsorbed A and B components, which results alternatively in spontaneous transitions from a state ‘A in B’ to a state ‘B in A’ and vice versa, with simultaneous dramatic change in the spot configurations under A and B, as well as changes in the chemical potentials of adsorbed A and B at the inversion points, certain minimal parts of the surface under A and B being permanently occupied by each of the components. This latter signifies that the non-complex-forming hydrocarbon hinders the complete transition of the urea to its inclusion compound phase.

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Abstract  

The results of investigation of the influence of encapsulation on the mechanism of thermal decomposition of cyanide transition metal complexes, based on data obtained by methods of differential thermal analysis (inert atmosphere) and thermodesorption (mass-spectral monitoring of gaseous products) are represented. It was established, that encapsulation of cyanide iron(II) and cobalt(III) complexes in faujasite type zeolite results in the hydrolytic mechanism of thermal destruction of complexes, unlike to bulk analogues, which is determined by essential decreasing of the temperature of complex anions encapsulated destruction beginning, up to temperatures while zeolite water molecules are saved; the gaseous products of thermal destruction composition is determined by the peculiarities of localization of cations of different nature in inclusion compounds.

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