Thermal properties of thiocyanatocopperc(II) complexes with picolines and lutidines

The thermal properties of coordination compounds of the composition Cu(NCS)₂L₂ (whereL=pyridine, 2-, 3- and 4-picoline, and 2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-lutidine) are dealt with. The thermal decomposition of these compounds begins with the release of the ligandL. The compounds with pyridine derivatives containing a methyl substituent at position 2 show a markedly decreased initial decomposition temperature. It was found that X-ray irradiation caused a reduction of the central atom Cu(II) in the coordination compounds under investigation. X-ray electron spectra data showed the stability of the compounds Cu(NCS)₂L₂ withL=picoline or lutidine having a methyl substituent at position 2 to be distinctly lower in the surface layers. From the given series, the compounds Cu(NCS)₂(pyridine)₂ and Cu(NCS)₂(3,5-lutidine)₂ exhibit an analogous course of thermal decomposition in nitrogen atmosphere up to 600°. The stoichiometries of thermal decomposition are discussed.

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Zusammenfassung Der Artikel befaßt sich mit den thermischen Eigenschaften von Koordi-nationsverbindungen der Zusammensetzung Cu(NCS)₂ L ₂ (L= Pyridin, 2-, 3-, 4-Pikolin, 2,3-, 2.4-, 2,5-, 2,6-, 3,4- und 3,5-Lutidin). Die thermische Zersetzung dieser Verbindungen beginnt mit der Abspaltung des LigandenL. Die Verbindungen mit Pyridinderivaten, welche einen Methylsubstituenten in Position 2 im Pyridinring enthalten, zeigen eine deutlich herabgesetzte anfängliche Zersetzungstemperatur. Es wurde gefunden, daß die Röntgenbestrahlung eine Reduktion des zentralen Cu(II)-Atoms bei den untersuchten Koordinationsverbindungen herbeiführte. Die Daten der Röntgen-Elektronenspektren zeigten, daß die Stabilität der Verbindungen Cu(NCS)₂L₂ mitL=Pikolin oder Lutidin, welche einen Methylsubstituenten in Position 2 enthalten, in den Oberflächenschichten wesentlich geringer ist. Von der gegebenen Reihe der Verbindungen zeigen Cu(NCS)₂(Pyridin)₂ und Cu(NCS)₂(3,5-Lutidin)₂ in Stickstoff-Atmosphäre bis zu 600° einen ähnlichen Verlauf der thermischen Zersetzung. Die Stöchiometrie ihrer thermischen Zersetzung wird beschrieben.

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Résumé L'article a trait aux propriétés thermiques des composés de coordination de composition Cu(SCN)₂L₂ (L=pyridine, 2-, 3-, 4-picoline, 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-lutidine). La décomposition thermique de ces composés commence avec la libération du ligandL. Les composés avec des dérivés de la pyridine contenant un substituant méthyle en position 2 sur le cycle de la pyridine présentent une température initiale de décomposition qui se trouve abaissée de manière appréciable. On observe que le traitement aux rayons X provoque une réduction de l'atome central Cu(II) dans les composés de coordination étudiés. Les données fournies par les spectres électroniques des rayons X ont montré que la stabilité des composés Cu(SCN)₂L₂ avecL= picoline ou lutidine, ayant un substituant méthyle en position 2, est nettement plus faible dans les couches superficielles. Dans cette série de composés, Cu(SCN)₂ (pyridine)₂ et Cu(SCN)₂(3,5-lutidine)₂ montrent, en atmosphère d'azote, jusqu'à 600°, un processus analogue de décomposition thermique. La stoechiométrie de leur réaction de décomposition thermique est examinée.

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Cu(NCS)₂L₂ L=, 2-, 3-, 4- , 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-. L. 2- . , , Cu(II). , Cu(NCS)₂L₂ c L= , 2, . Cu(NCS)₂ ( )₂ Cu(NCS)₂ (3,5-)₂ 600°. .

     

Kinetic analysis of thermogravimetric data. XX. Study of the thermal decomposition of some tetrathiocyanato-diamino-chromate complexes with derivatograph

The thermal decompositions of 8 complexes of the type A · H[Cr(NCS)₄(am)₂] (A=NH₃, pyridine,-picoline or aniline, andam=NH₃ or aniline) and of 14 complexes of the type M[Cr(NCS)₄(am)₂] (M=K, Ag, Tl, 1/2 Cd, 1/2 Pb or 1/3 Bi, andam=NH₃, benzylamine or aniline derivatives) were studied by means of a derivatograph. In the case of the A · H salts the formation of Cr(NCS)₃ was observed as a labile intermediate. Characteristic temperatures are discussed in terms of the polarizing effect of the outer sphere cations and of the nucleophilic character of the ligands. The results are compared with those obtained in the thermal decompositions of the analogous salts of the complex acid H₃[Cr(NCS)₆].

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Zusammenfassung Die thermische Zersetzung von 8 Komplexverbindungen des Typs A ·H[Cr(NCS)₄(am)₂] (A=NH₃, Pyridin, -Picolin, Anilin und am=NH₃ und Anilin) und von 14 Komplexen des Typs M[Cr(NCS)₄(am)₂] (M=K, Ag, Tl, 1/2 Cd, 1/2 Pb, 1/3 Bi und am=NH₃, Anilin und Anilinderivate) wurde mit dem Derivatographen untersucht. Im Falle der A. H Salze wird die Bildung von Cr(NCS)₃ als labiles Zwischenprodukt beobachtet. Die charakteristischen Temperaturen und kinetischen Parameter werden abgeleitet und auf der Basis der molekularen Struktur erörtert. Im Falle der M Salze werden die DTAPeaks aufgrund des Polarisationseffektes der Kationen der äußeren Sphäre und des nukleophilen Charakters der Liganden diskutiert. Die Ergebnisse werden mit jenen der thermischen Zersetzung der analogen Salze des H₃[Cr(NCS)₆] Komplexes verglichen.

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A. H[Cr(NCS)₄ ()₂], — , , - , «» . M[Cr(NCS)₄ ()₂], -, Ag, Tl, 1/2 Cd, 1/2Pb 1/3 Bi, « » — , . . Cr(NCS)₃, . , . , - . H₃[Cr(NCS)₆].

     

Influence of HCl on butene isomerization catalyzed by ethanolic rhodium trichloride II. Calculation and interpretation of the rate constants of the triangle scheme

The values of the rate constants of the triangle scheme, calculated by means of a non-linear least-squares method, depend systematically on the HCl concentration. The alteration of the cis-trans selectivity expressed by the ratio k_1c/k_1t might indicate a change in the mechanism of isomerization with the HCl concentration.

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, , . - , k_1c/k_1t, .

     

Thermal and calorimetric investigations on crystalline hydrates of barium hydroxide and their deuterated analogues

The thermal decompositions of Ba(OH)₂ · 8H₂O, Ba(OH)₂ · 8D₂O, Ba(OH)₂ · H₂O and Ba(OH)₂ · D₂O were studied and the phase transitions were identified by DSC and DTA methods. The corresponding enthalpy changes were determined and compared with those calculated from the thermodynamic data. A decrease of the thermal stability was demonstrated for the deuterated crystal hydrates in comparison with the normal ones.

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Zusammenfassung Die thermische Zersetzung von Ba(OH)₂ · 8H₂O, Ba(OH)₂ · 8D₂O, Ba(OH)₂ · H₂O und Ba(OH)₂ · D₂O wurde untersucht. Phasenübergänge wurden mittels DSC und DTA ermittelt. Die entsprechenden Enthalpieveränderungen wurden bestimmt und mit den aus thermodynamischen Daten berechneten Werten verglichen. Die deuterierten Kristallhydrate sind thermisch weniger stabil als die leichtes Kristallwasser enthaltenden Verbindungen.

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()₂ · 8₂, ()₂ · 8D₂O, Ba(OH)₂·H₂O Ba(OH)₂·D₂O. , . .

     

Preparation and properties of cyclodextrin inclusion compounds of organometallic complexes. Ferrocene inclusion compounds

Inclusion compounds of ferrocene(FcH) and its derivatives with cyclodextrins(CDs; -CD, -CD, and -CD) were prepared. CD-ferrocene inclusion compounds were obtained in a crystalline state in high yield. -CD and -CD formed 11 stoichiometric inclusion compounds with ferrocene and its derivatives. -CD formed 21 (CD:guest) complexes with ferrocene and the monosubstituted derivatives, but did not form complexes with 1,1-disubstituted derivatives, -CD-FcH and -CD-FcH complexes are thermally stable and do not liberate ferrocene on heating at 100°C in vacuo. The cyclodextrin inclusion compounds were characterized by¹H-NMR, IR, UV, and CD spectra. A large positive induced Cotton effect was observed in the case of -CD-FcH complex, while the -CD-FcH complex showed a negative spectrum. The binding mode is discussed. -Cyclodextrin was found to form inclusion complexes in ethylene glycol, diethylene glycol, triethylene glycol, methyl cellosolve, ethyl cellosolve, methyl alcohol, and glycerine solutions. -CD also formed complexes in ethylene glycol solution. The binding of ferrocene by -CD is stronger in ethylene glycol than in dimethyl sulfoxide and dimethyl formamide.     

Isomeric composition of ditolyls formed upon the thermal decomposition of an anionic Pt(IV) σ-tolyl chloride complex

Conclusion Heating a solution of PtCl₆ ^2– ions and toluene in CF₃CO₂H-H₂O leads to the formation of a platinum(IV) -tolyl complex which decomposes in the presence of free toluene to give 3,3-, 4,4-, 3,4-, 2,3- and 2,4-ditolyls.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2377–2380, October, 1986.This study was carried out in the framework of the Cooperation Program of Catalysis Scientists at the academies of sciences of the Socialist countries.     

N-acetylindoxyl in the synthesis of new condensed heterocycles

Derivatives of a new heterocyclic system thieno[2,35,6]pyrimido[3,4-a]indole, were obtained by the reaction of substituted N,O-diacetylindoxyls with excess N-(2-methyl-3-ethoxycarbonyl-4-thienyl)hydrazine. The reaction of N-acetylindoxyl and 4-hydrazinouracil forms 12-amino-1,3-dioxo-2,4,6-trimethylpyrimido[5,45,6]pyrimido[3,4-a]indole.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1343–1345, October, 1987.     

On the use of a dead-time meter for pile-up corrections

Correction for pile-up losses in the amplifier is possible by the dead-time fraction indicator of the ADC in case of long-lived radionuclides. If the dead-time meter has been calibrated, an accuracy of 1.5% is feasible up to a dead-time fraction of 25%. The precision decreases from 1.5% at 10% dead-time fraction to 3% at a deadtime fraction of 30%.     

Thiazolobenzo-1, 2, 3-thiadiazoles and derived cyanine dyes

The following tricyclic heterocyclic compounds are synthesized: 2-methylthiazolov (5, 4-e) benzo-1, 2, 3thiadiazole, 2-methylthiazolo (4, 5-e) benzo-1, 2, 3-thiadiazole, 2-methylthiazolo (4, 5-g) benzo-1, 2, 3-thiadiazole, and 2-methylthiazolo (5, 4-g) benzo-1, 2, 3-thiadiazole. The quaternary salts of these bases are used to prepare symmetrical and unsymmetrical trimethinecyanines and dimethinemercocyanines containing N-ethylrhodanine residues. The absorption maxima of these dyes are shifted toward the long-wave region as compared with the corresponding thiacyanines.     

Use of α-2-cyanoethyl tert-butoxycarbonylaspartate as an intermediate for synthesis of β-esters

The use of -2-cyanoethyl Boc-aspartate is proposed for the first time for the synthesis of -esters of Boc-aspartic acid. The -2-cyanoethyl protective group is selectively split out by strong organic bases under hydrolytic conditions without the -ester bond being affected. Using the -2-cyanoethyl derivative, -cyclohexyl, -benzyl, and -tert-butyl Boc-aspartates have been synthesized in good yields.All-Union Scientific-Research Institute of Molecular Biology. Vektor Scientific-Industrial Association. Ministry of the Medical and Biochemical Industries, Koltsovo, Novosibirsk Province. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 241–245, March–April, 1990.     

On the crystal chemistry of three copper(II)-arsenates: Cu3(AsO4)2-III,Na4Cu(AsO4)2, and KCu4(AsO4)3

The three copper(II)-arsenates were synthesized under hydrothermal conditions; their crystal structures were determined by single-crystal X-ray diffraction methods:Cu₃(AsO₄)₂-III:a=5.046(2) Å,b=5.417(2) Å,c=6.354(2) Å, =70.61(2)°, =86.52(2)°, =68.43(2)°,Z=1, space group ,R=0.035 for 1674 reflections with sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a=4.882(2) Å,b=5.870(2) Å,c=6.958(3) Å, =98.51(2)°, =90.76(2)°, =105.97(2)°,Z=1, space group ,R=0.028 for 2157 reflections with sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a=12.234(5) Å,b=12.438(5) Å,c=7.307(3) Å, =118.17(2)°,Z=4, space group C2/c,R=0.029 for 1896 reflections with sin / 0.80 Å^–1.Within these three compounds the Cu atoms are square planar [4], tetragonal pyramidal [4+1], and tetragonal bipyramidal [4+2] coordinated by O atoms; an exception is the Cu(2)^[4+1] atom in Cu₃(AsO₄)₂-III: the coordination polyhedron is a representative for the transition from a tetragonal pyramid towards a trigonal bipyramid. In KCu₄(AsO₄)₃ the Cu(1)^[4]O₄ square and the As(1)O₄ tetrahedron share a common O—O edge of 2.428(5) Å, resulting in distortions of both the CuO₄ square and the AsO₄ tetrahedron. The two Na atoms in Na₄Cu(AsO₄)₂ are [6] coordinated, the K atom in KCu₄(AsO₄)₃ is [8] coordinated by O atoms.Die drei Kupfer(II)-Arsenate wurden unter Hydrothermalbedingungen gezüchtet und ihre Kristallstrukturen mittels Einkristall-Röntgenbeugungsmethoden ermittelt:Cu₃(AsO₄)₂-III:a = 5.046(2) Å,b = 5.417(2) Å,c = 6.354(2) Å, = 70.61 (2)°, = 86.52(2)°, = 68.43(2)°,Z = 1, Raumgruppe ,R = 0.035 für 1674 Reflexe mit sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a = 4.882(2) Å,b = 5.870(2) Å,c = 6.958(3) Å, = 98.51(2)°, = 90.76(2)°, = 105.97(2)°,Z = 1, Raumgruppe ,R = 0.028 für 2157 Reflexe mit sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a = 12.234(5) Å,b = 12.438(5) Å,c = 7.307(3) Å, = 118.17(2)°,Z = 4, Raumgruppe C2/c,R = 0.029 für 1896 Reflexe mit sin / 0.80 Å^–1.Die Cu-Atome in diesen drei Verbindungen sind durch O-Atome quadratisch planar [4], tetragonal pyramidal [4 + 1] und tetragonal dipyramidal [4 + 2]-koordiniert; eine Ausnahme ist das Cu(2)^{[4 + 1]}-Atom in Cu₃(AsO₄)₂-III: Das Koordinationspolyeder stellt einen Vertreter des Übergangs von einer tetragonalen Pyramide zu einer trigonalen Dipyramide dar. In KCu₄(AsO₄)₃ haben das Cu(1)^[4]O₄-Quadrat und das As(1)O₄-Tetraeder eine gemeinsame O—O-Kante von 2.428(5) Å, was eine Verzerrung der beiden Koordinationsfiguren CuO₄-Quadrat und AsO₄-Tetraeder bedingt. Die zwei Na-Atome in Na₄Cu(AsO₄)₃ sind durch O-Atome [6]-koordiniert, das K-Atom in KCu₄(AsO₄)₃ ist [8]-koordiniert.

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Zur Kristallchemie dreier Kupfer (II)-Arsenate: Cu₃(AsO₄)₂-III, Na₄Cu(AsO₄)₂ und KCu₄(AsO₄)₃

     

Stereochemistry of nitrogenous heterocycles. 61. Synthesis and configuration of an eighth isomer of 2-methyl-4-hydroxydecahydroquinoline

Reduction of 1-benzoyl-2-methyl-4-oxo-cis-decahydroquinoline with sodium borohydride and sodium in alcohol has given 1-benzoyl-2-methyl-4-hydroxy-cis-decahydroquinoline, which exists in the steroidal conformation with diaxial , -substituents in the piperidine ring and with an equatorial hydroxy-group. Debenzoylation of this has given the last of the eight theoretically possible isomers of 2-methyl-4-hydroxydecahydroquinoline, namely 2-methyl-4-hydroxy-cis-decahydroquinoline, which exists in the nonsteroidal conformation with an axial hydroxy-group.For communication 60, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 238–243, February, 1987.     

3-Aminoalkyl-5-methyl-benzo[b]thiophene

Zusammenfassung Ausgehend von -[5-Methyl-benzo[b]thienyl-(3)]-propionsäure wurde eine Reihe von 5-Methyl-benzo[b]thiophenen mit einer Aminoalkylsubstitution in 3-Stellung dargestellt: 3-(-Aminoäthyl)-5-methyl-benzo[b]thiophen durchCurtius-Abbau des Azids und 3-(-Aminopropyl)-5-methyl-benzo[b]thiophen sowie N-Substitutionsprodukte davon durch LiAlH₄-Reduktion der entsprechenden Amide.

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5-Methyl-benzo[b]thiophenes having an aminoalkyl substituent in position 3 were prepared from -[5-methyl-benzo[b]-thienyl-(3)]-propionic acid: 3-(-aminoethyl)-5-methyl-benzo[b]-thiophene byCurtius rearrangement of the azide, and 3-(-aminopropyl)-5-methyl-benzo[b]thiophene as well as some of its N-derivatives by reduction of the corresponding amides with LiAlH₄.

     

Analytic evaluation of multicenter integrals for gaussian-type orbitals

This work contains the evaluation of multicenter integrals with Cartesian Gaussian functions occurring in ||||² These integrals have to be used if it is necessary to calculate the lower bounds for eigenvalues with the method of the minimization of the variance [1], Considering the varianceF() = ||H||² - (H!| )², the integrals from (HY, Y) are well known in contrast to those for ||H ||².     

Floroselin, a new coumarin from the roots of Seseli sessiliflorum

Conclusions A new coumarin has been isolated from the roots ofSeseli sessiliflorum for which the structure of 3-angeloyloxy-2,2-dimethyl-4-(trans-3-methylthioacryloyloxy)-3, 4-dihydropyrano-5,6:8,7-coumarin has been proposed. This is the first time that esters of 3-methylthioacrylic acid have been found in the coumarin series.All-Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 517–521, September–October, 1970.     

Changes undergone by 2-amino-N-(pyridyl-3′) anilinesunder pschorr reaction conditions

Reaction of 2 -nitroaniline with 3 -brornopyridine, 3 -iodo-5 -methylpyridine, and 3-iodo-6-methylpyridine gives 54–73% yield of the hitherto unknown 2-nitro-N-(pyridyl-3) aniline, 2-nitro-N-(5 -methylpyridyl3) aniline, and 2-nitro-N-(6-methylpyridyl-3) aniline. The nitro compounds prepared can easily be reduced to the corresponding amino-N-pyridylanilines. The amino compounds do not form carbolines under Pschorr reaction conditions, but are converted to triazoles or N -(pyridyl-3)-aniline.     

Faster analysis by reversed-phase high-performance liquid chromatography

Summary Many analysts are not taking full advantage of the high speed possibilities of modern LC. Some analytical procedures reported in the literature, and many in regular use in control laboratories, could be achieved in less time without loss in precision. Some factors which affect retention times are discussed and the advantages and disadvantages of employing shorter column lengths and finer packing materials in reversed-phase HPLC are examined. The effect on efficiency of increased flow rates with 10,5 and 3 m ODS materials is shown. The ability to couple shorter column lengths without loss of efficiency is also demonstrated. This allows a minimum length to be selected that gives adequate resolution. Examples of high speed separations are shown and limitations in state of the art HPLC equipment and chromatographic data systems are discussed briefly.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Selective aziridination of olefinic esters

Summary Oxidation of 3-amino-2-isobutylquinazoline-4-one (2) with lead tetraacetate at –20°C gave N-acetoxyamino-2-isobutylquinazolin-4-one (3), which selectively aziridinated olefinic esters to yield substituted 1-(2-isobutylquinazolin-4-one-3-yl)-aziridine-2-carboxylates5a–q.

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Selektive Aziridinierung von olefinischen Estern

Zusammenfassung Oxidation von 3-Amino-2-isobutylchinazolin-4-on (2) mit Bleitetraacetat bei –20°C ergab N-Acetoxyamino-2-isobutylchinazolin-4-on (3), welches mit verschiedenen olefinischen Estern selektiv substituierte 1-(2-Isobutylchinazolin-4-on-3-yl)-aziridin-2-carbonsäureester5a–q lieferte.

     

Phase equilibria in the Ag2Te-Cd system

The phase diagram of the Ag₂Te-Cd system, which is a polythermal section of the ternary system Ag-Cd-Te, was established by means of DTA and metallographic analysis. The diagram contains 32 phase regions, including the polymorphic modifications of Ag₂Te, solid solutions based on Ag₂Te and Cd, and two intermediate phases with variable compositions: Ag₂Cd_1+xTe and Ag₂Cd_5+xTe.

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Zusammenfassung Das Phasendiagramm des Systems Ag₂Te-Cd, eines polythermen Schnittes im ternären System Ag-Cd-Te, wurde aus DTA- und metallographischen Ergebnissen konstruiert. Das System besteht aus 32 Ein- und Zweistoffgebieten, darunter den polymorphen Modifikationen des Ag₂Te, festen Lösungen auf Basis Ag₂Te bzw. Cd, und ternären Phasen mit den variablen Zusammensetzungen Ag₂Cd_1+xTe und Ag₂Cd_5+xTe.

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Ag₂Te-Cd, AgCd-. , Ag₂Te, Ag₂Te Cd, Ag₂Cd_1+x Te Ag₂Cd_5+x Te.

     

Synthesis and Crystal Structure of the (batre)[CuBr4] Complex, where Batre is bis‐1,1′‐(4‐amino‐1,2,4‐triazolio)ethane

The (batre)[CuBr₄] complex is produced by the reaction of CuBr₂ and (batre)Br₂ in concentrated HBr; its crystal structure is determined. The acentric unit cell (Pn space group) has the following parameters: a = 7.626(2), b = 8.945(2), c = 11.702(2), = 96.69(3)°, V = 792.8(3)³, and Z=1 ((batre)[CuBr₄] composition). The structure of the complex is built up of [CuBr₄]^2- tetrahedral anions and (batre)²⁺ uncoordinated cations. The Cu—Br distances are 2.362–2.385 and the BrCuBr angles are 99.73–129.79°.