Correlation between structures and thermal properties of hydrated thallium(I) diborates; H2O-Tl2B4O7 phase diagram

Two synthetic hydrated thallium (I) diborates have been found in the liquidsolid equilibria of the 100° isotherm of the ternary system H₂O-B₂O₃-Tl₂O; they were characterized via the powder diagrams, but classical chemical analysis does not lead to the correct degree of hydration. Through TG of the powders, a complex process is found with no explanation. Structural resolution and TG of the monocrystals allow a correct explanation of the thermal dehydration: these thallium (I) diborates are two distinct compounds, Tl₂B₄O₇ · 3H₂O and Tl₂B₄O₇ · 1.5H₂O, which have their own process of dehydration; they contain infinite chains of polyanions and their structural formulae are Tl₂[B₄O₆ (OH)₂] · 2H₂O and Tl₄[B₈O₁₂ (OH)₄]H₂O; the latter polyanion may be considered as the dimer of the first.The H₂O-Tl₂B₄O₇ phase diagram was established by thermal analysis and solubility experiments, both under pressure; it allows the prediction that another hydrated thallium (I) diborate, Tl₂B₄O₇·H₂O, exists, with possible structural formula Tl₆[B₁₂O₁₈ (OH)₆]. Actually, only monocrystals of Tl₄[B₈O₁₂ (OH)₄]·H₂O have been obtained hydrothermally from Tl₂[B₄O₆ (OH)₂] · 2H₂O.

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Zusammenfassung Im ternären System H₂O-B₂O₃-Tl₂O liegen bei 100° bei Einstellung des Gleichgewichtes flüssig-fest zwei hydratisierte Thallium (I) -diborate vor; diese wurden durch Pulverdiagramme charakterisiert, die klassische chemische Analyse ergab jedoch nicht den richtigen Hydratationsgrad. Bei TGA von Pulvern verläuft ein komplexer Prozeß, für den keine mögliche Erklärung gegeben werden kann. Strukturaufklärung und TGA mit Einkristallen ermöglichen eine korrekte Erklärung der thermischen Dehydratisierung: die hydratisierten Thallium (I) -diborate sind zwei verschiedene Verbindungen der Zusammensetzung Tl₂B₄O₇· 3H₂O und Tl₂B₄O₇· 1.5H₂O mit unterschiedlichem Dehydratisierungsverlauf, die Polyanionketten enthalten und durch die Strukturformeln Tl₂[B₄O₆ (OH)₂] · 2H₂O bzw. Tl₄[B₈O₁₂ (OH)₄] · H₂O zu beschreiben sind. Das Polyanion der zweiten Verbindung kann als Dimeres des der ersten angesehen werden. Das Phasendiagram H₂O-Tl₂B₄O₇ wurde durch unter Druck ausgeführte thermische Analyse und Löslichkeitsexperimente aufgestellt. Aus diesem Phasendiagramm kann die Existenz eines anderen hydratisierten Thallium (I) -diborats, Tl₂B₄O₇ · H₂O, mit der möglichen Strukturformel Tl₆[B₁₂O₁₈ (OH)₆] vorausgesagt werden. In Wirklichkeit wurden aber nur Einkristalle von Tl₄[B₈O₁₂ (OH)₄]·H₂O durch hydrothermale Behandlung von Tl₂[B₄O₆ (OH)₂] · 2H₂O erhalten.

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₂-₂₃-l₂ 100° , . , . : l₂₄₇·₂ l₂₄₇·1.5₂, . l₂[₄₆()₂]· 2₂ l₄[₈₁₂()₄]·₂. . ₂-l₂₄₇. , l₂₄₇·₂ l₆[₁₂₁₈()₆]. , l₄[₈₁₂()₄]·₂ l₂[₄O₆()₂]·2₂O.

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Paper presented at the World Conference on Thermal Analysis Amsterdam, 1984.     

A novel method for the dealumination of zeolites

A wide range of halogen containing reagents (metal halides, oxyhalides, acid halides, etc.) are found to interact from the gas phase with exchange ions of zeolites and to effect dealumination at elevated temperatures. The incorporation of extraneous ions into the framework by this technique is not impossible theoretically. The importance of the method in the preparation of dealuminated and/or metal containing catalysts is discussed.

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, , ( , , ), , . . / , .

     

Synthesis of some new esters of 1-n-butyl-2, 5-dimethyl-4-ethynyl (ethyl)-and 1-allyl-2, 5-dimethylpiperid-4-ols

The following are synthesized: 1-n-butyl-2e, 5e-dimethyl-4e-ethynylpiperid-4a-yl benzoate ( isomer), 1-n-butyl-2e, 5e-dimethyl-4a-ethynyl (ethyl) piperid-4e-yl o-chlorobenzoate ( isomers), 1-allyl-2e, 5e-dimethylpiperid-4e-yl o-chlorobenzoate ( isomer).     

Synthesis and Dehydrohalogenation of 3 β-Chloro-5 α,7 α-dibromo-6-ketosteroids of the Stigmastane and Cholestane Series

3-Chloro-5,7-dibromo-6-ketosteroids 5a and 5b are synthesized from -sitosterol (1a) and cholesterol (1b). Dehydrohalogenation of these forms 7-bromo-2,4-dien-6-ones (6a-b), 2,4-dien-6-ones (7a-b), and 14-hydroperoxy-2,4,7-trien-6-ones (8a-b). Woodward hydroxylation of dienone 6a produces 2-iodo-7-bromo-3-acetoxy-⁴-6-ketone 9 and 7-bromo-2,3-diacetoxy-⁴-6-ketone 10. 2-Iodo-3-acetoxy-^4,7,14-trien-6-one 11 is prepared analogously from trienone 8a.     

13C NMR Spectroscopy on the Complexation of α-Cyclodextrin with 1-Alkanols and 1-Alkanoate Ions

Binding constants for -cyclodextrin ( -CD) complexes with 1- alkanols and 1- alkanoate ions were determined by analyzing changes ( ) in chemical shifts of guest ¹³C NMR signals with -CD concentration. The guests gave well-separated ¹³C NMR signals. The curve-fitting analyses of for individual carbons upon assumption of a simple 1:1 complexation gave virtually the same binding constants (K₁) in the cases of guests with relatively short alkyl chains, such as 1-propanol, 1-butanol, 1- pentanol , 1- butanoate , 1- pentanoate , and 1-hexanoate. However, thus obtained individual K₁ values were significantly different from one another, when the guests had relatively long alkyl chains such as 1- hexanol , 1- heptanol , and 1-octanoate. In these guests, satisfactorily consistent K₁ values were obtained by the curve-fitting analyses of for individual carbons upon an assumption that not only 1:1 but also 2:1 (host:guest) complexation occurs.     

Triterpene glycosides ofLeontice eversmannii

Conclusions The structure of leontoside E has been established as a hexaoside of hederagenin. Its O-glycosidic moiety is branched and consists of O--D-glucopyranosido(1 » 4)-O--D-glucopyranosido(1 » 3)-O--L-arabopyranose and its O-acyl glycosidic moiety is O--L-rhamnopyranosido(1 » 4)-O--D-glucopyranosido(1 » 6)-O--D-glucopyranose.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 4, pp. 216–221, 1968     

Synthesis and some properties of the methyl ester and N,N-diethylamide of 2-azido-5-phenyl-4-thiazolecarboxylic acid

The methyl ester and N,N-diethylamide of 2-azido-5-phenyl-4-thiazolecarboxylic acid were obtained by the reaction of the corresponding 4-substituted 2-hydrazino-5-phenylthiazole with NaNO₂ in acid media. IR and UV spectroscopy were used to show that the compounds synthesized retain azide form in both the crystalline state and in solution. The reaction of azides with dicarbonyl compounds gave derivatives of 2-[5-methyl-4-acetyl-or 2-[5-methyl-4-ethoxycarbonyl-1,2,3-triazol-1-yl]-5-phenylthiazole-4-carboxylic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 710–714, May, 1993.     

Effect of the state of vanadium cations on the IR spectra of adsorbed carbon monoxide

ESR and IR-spectrosocpic studies of the effect of the state of vanadium ions on the IR-spectra of adsorbed CO have revealed complex formation of CO with V⁴⁺ (vCO at 2192 and 2205 cm^–1) and V³⁺ (vCO at 2178 and 2185 cm^–1) ions.

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-- - CO. CO V⁴⁺ (vCO 2192, 2205 cm^–1) V³⁺ (vCO 2178, 2185 cm^–1).

     

Comparative study on inclusion complexations of antiinflammatory drug flurbiprofen with β-cyclodextrin and methylated β-cyclodextrins

Abstruct Some physicochemical properties of methylated -cyclodextrins, i.e., heptakis(2,6-di-O-methyl)--cyclodextrin (DM--CyD) and heptakis(2,3,6-tri-O-methyl)--cyclodextrin (TM--CyD) were compared with those of natural -cyclodextrin (-CyD). Inclusion behaviors of -CyD and methylated -CyDs in water and in solid state were studied by solubility analysis, spectroscopies (UV, CD,¹³C-NMR and IR), X-ray diffractometry and thermal analysis, using an antiinflammatory drug flurbiprofen (FP) as a guest molecule. The spectral data suggest that the inclusion mode of FP-TM--CyD is somewhat different from those of FP--CyD and FP-DM--CyD. The solid complexes of FP with - and methylated -CyDs were obtained in molar ratio of 11, and their dissolution behavior and release from suppository base were examined. The data are presented suggesting that DM--CyD is particularly useful for improving the pharmaceutical properties of FP in various dosage forms.     

Synthesis of spiro[isoquinoline-4,4′-pyran]-3-imines

A method has been developed for the synthesis of 4-[2-(bromomethyl)phenyl] tetrahydro-2H-4-pyrancarbonitrile and a study was carried out on the reaction of this compound with primary amines, which, depending on the conditions, leads to either 4-[2-(R-aminomethyl)phenyl]tetrahydro-2H-4-pyrancarbonitriles or hydrobromides of 2-R-aryl-2,3,2,3,5,6-hexahydrospiro[isoquinoline-4(1H),4-pyran]-3-imines.Taras Shevchenko Kiev University, 252017 Kiev, Ukraine; e-mail: vkysil@mail.univ.kiev.ua. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1035–1041, August, 2000.