Thermal analysis of two series mono - and di -azocalix[4]arene derivatives
12 Feb 2011-Journal of Thermal Analysis and Calorimetry (Springer Netherlands)-Vol. 105, Iss: 1, pp 341-347
TL;DR: In this paper, thermal decomposition of mono- and di-azocalix[4]arene derivatives (A1-A8 and B1-B8) was investigated by means of thermogravimetry (TG), differential thermal analysis (DTA) and derivative thermograves (DTG), and the degree amount of volatile pyrolysis products were determined in air atmosphere using TG, DTA and DTG curves.
Abstract: In the present study, thermal decomposition of mono- and di-azocalix[4]arene derivatives (A1–A8 and B1–B8) was investigated by means of thermogravimetry (TG), differential thermal analysis (DTA) and derivative thermogravimetry (DTG). The exclusion of methanol, hydrolysis of benzoyl ester and methyl ketone groups in lower rim, and decomposition of azo groups in upper rim have occurred during thermal analysis, consecutively. The thermal decomposition degrees amount of volatile pyrolysis products were determined in air atmosphere using TG, DTA and DTG curves. In conclusion, the thermal analyses of azocalix[4]arenes demonstrated that its stability depends on the substituted groups and their positions in the calix[4]arene structure.
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TL;DR: A comprehensive review of azo-containing macrocyclic compounds reported up to now can be found in this article, where representative works on azo macrocycles with their molecular recognition, self-assembly and application emphasized.
Abstract: Macrocyclic compounds play an important role in supramolecular chemistry accounting for their unique recognition and self-assembly properties and potential applications in biomedicine and material science. Azo compounds display promising capability in fields of molecular switches, polymers, smart materials and molecular machines because of their photoactive and electroactive properties. Introducing azo groups into macrocycles gives them signal moieties, additional recognition sites, photo-responsive properties, and so on. Herein, we comprehensively review the structures of azo-containing macrocyclic compounds reported up to now. Then we describe representative works on azo macrocycles with their molecular recognition, self-assembly and application emphasized.
27 citations
TL;DR: In this article, the thermal behavior of three ester derivatives of p-tert-butyl calix[n]arene (n = 4, 6 and 8) in comparison with the parent calixarene was investigated by means of the thermogravimetric (TG) and differential thermograimetic (DTG) analysis and differential scanning calorimetry (DSC).
Abstract: The thermal behaviour of three ester derivatives of p-tert-butyl calix[n]arene (n = 4, 6 and 8) in comparison with the parent calixarene was investigated by means of the thermogravimetric (TG) and differential thermogravimetic (DTG) analysis and differential scanning calorimetry (DSC). The thermal stability domains, the composition of the pyrolysis products and the thermal effects, were determined on the basis of TG, DTG and DSC plots registered in nitrogen flow. Attempts to analyse the evolved gases by TG-FTIR coupling were also performed. It was demonstrated that the stability of the calix[n]arene derivatives depends on both the size of the hydrophobic cavity and number of the substituting groups grafted on the calix[n]arene skeleton.
21 citations
TL;DR: In this paper, the synthesis of chromogenic di-substituted azocalix[4]arene derivatives is described, and the complexing properties of these compounds were studied by the liquid-liquid extraction of selected metal cations (Sr2+, Ag+, Hg+, Co2+ Hg2+, Co 2+, Ni2+, Cu2+, Pb2+, Cr3+, Al3+), but almost no affinity to other metals.
20 citations
TL;DR: In this paper, all the thermal studies of parent calix[n]arenes, azocalix[4]arene derivatives and their complexes containing lower and upper rim functionalized groups are reported.
Abstract: Calixarenes have been widely regarded as an important class of macrocyclic host molecules, due to their efficient and highly selective binding properties towards specific metal ions. Azocalixarenes, containing single conjugated chromophore azo (‒N˭N‒) group in p- positions are synthesized by “one-pot” procedures with satisfactory yields. Their structures (as solid and liquid) are elucidated by UV-Vis, FT-IR, 1H and 13C-NMR spectroscopic methods, as well as elemental analysis techniques. Thermal stability of calixarenes is very important because of their potential applications in high temperature processes such as the dyeing of textile fibers, ink-jet printing and photocopying and in high technology areas such as lasers and electro-optical devices. In this paper all the thermal studies of parent calix[n]arenes, azocalix[4]arene derivatives and their complexes containing lower and upper rim functionalized groups are reported. All the thermo analytical results such as the temperature ranges and peak temperat...
14 citations
TL;DR: In this paper, the ability of 1,3-alternate conformer of tert-butylcalix[4]arene with four n-propoxy substituents to detect nitrogen dioxide in reversible sensors was investigated.
Abstract: Simultaneous thermal analysis with evolved gas analysis (STA-EGA) was used to study the ability of 1,3-alternate conformer of tert-butylcalix[4]arene with four n-propoxy substituents (1) to be applied for detection of nitrogen dioxide in reversible sensors. Solid calixarene 1 forms an intensively colored charge-transfer complex (CTC) with gaseous NO2/N2O4. Using the STA-EGA method, the nature and conditions of CTC bleaching were characterized, including the conditions of its reversible change of color from white to dark blue and back at CTC formation and decomposition. For this, the thermal stability of CTC and its regeneration products were studied. This, together with the ion thermograms for evolved gases, gives the information on the oxidation of 1 by nitrogen dioxide if present.
12 citations
Cites background from "Thermal analysis of two series mono..."
...By this, host 1 differs from several other calixarenes, which have such transitions [1, 2, 12, 13]....
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References
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TL;DR: Novel strategies for cavity design using calix[n]arene skeletons, strategies that are intended to allow complexation of specific molecular targets or metal ions are described.
Abstract: Calixarenes are macrocyclic molecules, like crown ethers and cyclodextrins.1-7 Calixarenes made up of phenol and methylene units have many conformational isomers because of two possible rotational modes of the phenol unit: the oxygen-through-theannulus rotation and the para-substituent-throughthe-annulus rotation (Figure 1). The conformational isomers thus yielded afford a great number of unique cavities with the different size and the different shape. Recently, a number of strategies have been exploited by which not only the conformation of calix[4]arenes, but also those of calix[6]arenes and calix[8]arenes, can be immobilized. This means that our group can now design various calixarene-based receptors that show high selectivity for guest molecules and metal cations. In this review article, our group describe novel strategies for cavity design using calix[n]arene skeletons, strategies that are intended to allow complexation of specific molecular targets or metal ions.
1,216 citations
"Thermal analysis of two series mono..." refers background in this paper
...Numerous potential applications of calixarene derivatives such as specific ligands for cations, anions and host of neutral compounds have been reported previously [1–4]....
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401 citations
Book•
25 Jul 1997
TL;DR: Artificial neural networks as a semi-empirical modeling tool for physical property prediction in polymer science as mentioned in this paper have been used to predict physical properties of polyethylene under high pressure structure, stability, and degradation of PVC solution state of metal complex calixarenes and polymetric calixarixarene thermodynamic opportunity of degradation reaction initiation polymerization.
Abstract: Artificial neural networks as a semi-empirical modelling tool for physical property predictions in polymer science new generation high performance polymers by displacement polymerization acrylamide polymers transparent polyolefins the polyolefins stabilizers with intramolecular synergism high-temperature stabilization of polyolefins poly(malic acid) from natural sources stabilization of polyolefins gamma radiation induced preparation of polyelectrolytes and its use for treatment of waste water polyvinylchloride (PVC)/thermoplastic polyurethane (TPU) polymeric blends mechanical properties of ionomers and ionomer blends metallocene based polyolefins - product characteristics preparations and properties of porous poly(vinyl alcohol)-poly(vinyl acetate) composites hydrophobization of polyanionic polymers to achieve higher biological activity uniform latex particles reaction mechanism of vinyl polymerization with amine in redox and photo-induced charge-transfer initiation systems photoinitiation of free-radical polymerization by organometallic compounds chemical modification of polystyrenes in the presence of cationic catalysis and their industrial applications performance of polyethylenes in relation to their molecular structure the crystallization of polyethylene under high pressure structure, stability, and degradation of PVC solution state of metal complex calixarenes and polymetric calixarenes thermodynamic opportunity of degradation reaction initiation polymerization by ylides. (Part contents).
211 citations
TL;DR: The influence of both the guest structure and the shape and flexibility of the hosts on the complexstability in the gas phase and (mainly) in solution is considered in this article, where five structural types of organic cations are reviewed.
Abstract: Calix[n]arenes represent an interestingclass of preorganized aromatic hostsexhibiting an enhanced ability forcation-π interaction. Recent resultsobtained with the complexation of variouscalix[n]arenes and five structural typesof organic cations, namely ammonium ions,quaternary ammonium ions, phosphonium ions,iminium ions and tropylium ions are reviewed.The influence of both the guest structure and theshape and flexibility of the hosts on the complexstability in the gas phase and (mainly) in solutionis considered.
97 citations
TL;DR: In this paper, the title compound was used for preparation of complexes Cu2(ac)4(bfp)2 (8) and CoCl2(BFp) 2 (9), where ac=CH3CO 2 − 2 − 3 CO 2 and bfp=[1]benzofuro[3,2-c]pyridine.
Abstract: (E)-3-(1-Benzofuran-2-yl)propenoic acid (1) was prepared from 1-benzofuran-2-carbaldehyde under the Doebner’s conditions. The obtained acid was converted to the corresponding azide 2, which was cyclized by heating in diphenyl ether to [1]benzofuro[3,2-c]pyridine-1(2H)-one (3). This compound was aromatized with phosphorus oxychloride to chloroderivative 4 which was reduced with zinc and acetic acid to the title compound 5. [1]Benzofuro[3,2-c]pyridine-2-oxide (6) was synthesized by reaction of 5 with 3-chloroperoxybenzoic acid in dichloromethane. Treatment of 6 with benzoyl chloride and potassium cyanide (Reissert-Henze reaction) was shown to produce the corresponding [1]benzofuro[3,2-c]pyridine-1-carbonitrile (7). The title compound was used for preparation of complexes Cu2(ac)4(bfp)2 (8) and CoCl2(bfp)2 (9), where ac=CH3CO
2
−
and bfp=[1]benzofuro[3,2-c]pyridine. Both oxygen atom of carboxylate ions is used in the coordination to Cu(II). Thermal properties of the complexes 8 and 9 have been studied by TG and DTA and both complexes exhibited high thermal stability while complex 9 are thermally more stable than complex 8.
73 citations
"Thermal analysis of two series mono..." refers background in this paper
...Thermal analysis plays important role in structure and stability studies of both organic and inorganic compounds [10–12]....
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