Thermal properties of thio-and selenocyanatocopper(II) complexes with bipyridine and phenanthroline

The paper deals with the thermal properties of complex compounds of the general formula CuL₂(NCX)₂ (whereL=bipy or phen,X=S or Se). The phenanthroline complexes exhibit a higher thermal stability than those with bipyridine. For the latter complexes thermal decomposition begins with the release of bipyridine molecules, while for the phenanthroline complexes redox reactions of pseudohalogenide ligands with Cu(II) take place. The redox reactions start at a lower temperature for the selenocyanate complexes than for the thiocyanate complexes.

---

Zusammenfassung Vorliegende Arbeit behandelt die thermischen Eigenschaften von Komplexverbindungen der allgemeinen Formel CuL₂(NCX)₂ (mitL=Bipyridin oder Phenanthrolin undX=S oder Se). Die Phenanthrolinkomplexe zeigen eine grössere thermische Stabilität als die Bipyridinkomplexe. Die thermiscne Zersetzung letzterer beginnt mit der Abgabe von Bipyridinmolekülen, während bei den Phenanthrolinkomplexen Redoxreaktionen von Pseudohalogenidliganden·mit Cu(II) stattfinden. Diese Redoxreaktionen beginnen bei den Selenozyanatkomplexen bei niedrigeren Temperaturen als bei den Thiozyanatkomplexen.

---

CuL₂(NCX)₂, L= , X= . . , — . - , .

     

Thermal decomposition of crystalline molecular sieve (C3H7)3N-AlPO4-5

The thermal decomposition of (C₃H₇)₃N-AlPO₄-5 in inert and oxidizing gas atmospheres has been studied by TG, DTG and DTA in the temperature range 303–1273 K. The removal of tripropylamine occluded in the channels of the aluminophosphate occurs in a number of steps and is strongly influenced by the gas atmosphere.

---

Zusammenfassung Die thermische Zersetzung von (C₃H₇)₃N-AlPO₄-5 wurde in inerter und oxydierender Gasatmosphäre mittels TG, DTG und DTA im Temperaturbereich von 303–1273 K untersucht. Der Austritt des in den Kanälen des Aluminiumphosphats okkludierten Tripropylamins erfolgt über eine Anzahl von Stufen und wird stark von der Gasatmosphäre beeinflußt.

---

, (C₃H₇)₃N-AlPO₄-5 303–1273 . , , .

---

---

We are grateful to Dr. V. G. Gunjikar, Mr. J. S. Gujaral and Dr. (Mrs) A. Mitra of the Special Instrument Group of our Laboratory for their co-operation in the work.     

Salen and tetrahydrosalen nickel(II) and copper(II) complexes

The synthesis and characterisation of novel bis salen complexes, M(salenH2), N,N-bis-[5(1,1,3,3-tetramethyl- butyl)salicylidene]-1,2-diaminoethane complexes, (M=Ni or Cu), and the corresponding less studied, bis-tetrahydrosalen complexes, M[H2(salenH2)], N,N-bis-[2-hydroxy-5(1,1,3,3-tetramethylbutyl)benzyl]-1,2-diaminoethane complexes, (M=Ni or Cu), with a highly branched substitution pattern at C-5 of the benzene ring is described. The Schiff bases behave as dibasic tetradentate ligands. The tetrahydrosalen complexes show structural properties, chemical and thermal behaviour which is different from those of the corresponding salen complexes. The melting points and decomposition temperatures of these complexes were determined by d.s.c. and t.g.a.     

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.

---

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

     

Thermal properties of 5-(subst)-amino-1,2,3,4-thiatriazoles

The thermal properties of 5-(subst)-amino-1,2,3,4-thiatriazoles were studied using TG and DTA. 5-amino-1,2,3,4-thiatriazole was actively decomposed at the melting temperature. The active thermal decomposition proceeds at a very fast rate, being accompanied by exothermic reactions of recombination. In comparison with this, the different-5-(subst)-amino-1,2,3,4-thiatriazoles are decomposed at slower rates in several degradative steps. The effects of some substituents on the total course of thermal degradation are discussed.

---

Zusammenfassung Die thermischen Eigenschaften von 5-(subst)-Amino-1,2,3,4,-Thiatriazolen wurden mittels der Methoden TG und DTA untersucht. Das 5-Amino-1,2,3,4-Thiatriazol wurde bei der Schmelztemperatur aktiv zersetzt. Die aktive thermische Zersetzung verläuft mit einer sehr großen Geschwindigkeit und wird von den exothermen Reaktionen der Rekombination begleitet. Im Vergleich hierzu werden die verschiedenen 5-(subst)-Amino-1,2,3,4-Thiatriazole mit einer geringeren Geschwindigkeit, in mehreren Zersetzungsstufen abgebaut. Die Wirkung einiger Substituenten auf den Gesamtablauf der thermischen Zersetzung wird erörtert.

---

Résumé On a étudié par TG et ATD les propriétés thermiques des 5-(subst)-amino-1,2,3,4-thiatriazoles. Le 5-amino-1,2,3,4-thiatriazole se décompose activement à la température de fusion. La décomposition thermique active s'effectue avec une très grande vitesse et s'accompagne de réactions exothermiques de recombinaison. Par contre, les divers 5-(subst)-amino-1,2,3,4-thiatriazoles se décomposent avec une vitesse plus faible et en plusieurs étapes. On discute l'effet de quelques substituants sur le processus complet de la dégradation thermique.

---

, , 5-()--1,2,3,4-. 5--1,2,3,4- . , . , 5-()--1,2,3,4- . .

     

Temperature programmed desorption of NH3 and H2O from NH4NaX and CoNH4NaX zeolites

A study has been made of temperature programmed desorption (TPD) of NH₃ and H₂O from samples of NH₄X and CoNH₄X zeolites of various degree of exchange. NH₃ TPD peaks could be explained by interaction of NH₃ with different Brönsted and Lewis acidic centers. Moreover a water peak at high temperatures allowed interpretations of the dehydroxylation, and by reason of the characteristic desorption temperatures a particular state of the Co²⁺ ions in the CoNH₄X zeolites is postulated.

---

- () NH₃ H₂O NH₄X CoNH₄X . NH₃ NH₃ =qs . . Co²⁺ CoNH₄X.

     

Thermal and some other properties of the complexes crystallizing from the system Ni(II)-en-[Ni(CN)4]2−-H2O

Seven complex compounds exhibiting the compositions Ni(en)₃Ni(CN)₄·H₂O (I), Ni(en)₃Ni(CN)₄ (II),-Ni(en)₂Ni(CN)₄ (III), Ni(en)Ni(CN)₄·2H₂O (IV), Ni(en)Ni(CN)₄ (V), Ni(en)₂Ni(CN)₄ · 2.5H₂O (VI) and-Ni(en)₂Ni(CN)₄ (VII) were prepared from the system Ni-en-[Ni(CN)₄]^2–-H₂O. These compounds were examined by the methods of infrared spectroscopy, X-ray powder diffractometry, UV-VIS reflectance spectroscopy, and also by the measurement of magnetic moments. The thermal stability, the stoichiometry of thermal decomposition and the mutual transformations were investigated with a derivatograph. The reactions proceeding according to the following schemes were observed if the system was heated to appropriate temperature: (I)(II)(III)(V)(IV) and (VI)(VII)(III)(V)(IV) Process (VII)(III) represents isomerization. The reversibility of the process (V)(IV) is due to the high hygroscopicity of the anhydrous complex. The changes in structure in the course of the individual processes are discussed.

---

Zusammenfassung Aus einem System Ni-en-[Ni(CN)₄]^2–-H₂O wurden sieben Komplexe der Formeln Ni(en)₃Ni(CN)₄·H₂O (I), Ni(en)₃Ni(CN)₄ (II),-Ni(en)₂Ni(CN)₄ (III), Ni(en)Ni(CN)₄·2H₂O (IV), Ni(en)Ni(CN)₄ (V), Ni(en)₂Ni(CN)₄ · 2.5H₂O (VI) und-Ni(en)₂Ni(CN)₄ (VII) hergestellt. Diese Verbindungen wurden mittels IR-Spektroskopie, Röntgenpulverdiffraktometrie, UV-Reflexionsspektroskopie und durch Messungen des magnetischen Momentes untersucht. Die Wärmestabilität, die Stöchiometrie des thermischen Zerfalles und die gegenseitigen Umwandlungen wurden mittels eines Derivatographen untersucht. Wird das System auf geeignete Temperaturen erhitzt, kann der Reaktionsverlauf durch folgendes Schema dargestellt werden: (I)(II)(III)(V)(IV) und (VI)(VII)(III)(V)(IV).Der Prozeß (VII)(III) verkörpert eine Isomerisierung. Die Umkehrbarkeit von Prozeß (V)(IV) ist auf die ausgeprägten Hygroskopieeigenschaften des wasserfreien Komplexes zurückzuführen. Es werden die im Ablaufe der einzelnen Prozesse vorgehenden Strukturveränderungen besprochen.

---

Ni- -[No(N)]² -₂ Ni(en)₃Ni(CN)₄ · ₂ (I), Ni(en)₃Ni(CN)₄ (II),-Ni(en)₂Ni(CN)₄ (III), Ni(en)Ni(CN)₄-2H₂O (IV), Ni(en)Ni(CN)₄ (V), Ni(en)₂Ni(CN)₄ · 2,5H₂O (VI) -Ni(en)₂Ni(CN)₄ (VII). , , - , . , . (I)(II)(III)(V)(IV) (VI)(VII)(III)(V)(IV). (VII)(III) . (V)(IV) . .

     

Preparation and x-ray structure determination of penta-and tetracyano-oxomolybdenum(IV) anions. The influence of water on their reactivity

Summary Several penta-and tetracyanooxomolybdenum(IV) anions have been synthesized containing different numbers of H₂O molecules, either coordinated or present as crystallisation molecules. The influence of these molecules on the reactivity of the complex, especially towards O₂, is discussed. Three compounds were characterized by x-ray structure determination. [Mo(O)(CN)₅(H₂O)₂(MeCN)₂][PPh₄]₄Cl belongs to triclinic space group P-1 witha=13.146(3) Å,b=16.944(5) Å,c=21.761(6) Å, =84.72(2)°, =87.15(2)° and =85.25(2)°. The volume of the unit cell is 4678(6)ų withz=2. The structure was refined to R=6.5%. [Mo(O)(CN)₄(H₂O)·6H₂O][PPh₄]₂ belongs to monoclinic space group P2₁/n witha=15.313(2)Å,b=19.983(3)Å,c=17.006(2)Å, =100.51(2)°. The volume of the unit cell is 5117(3)ų withz=4. The structure was refined to R=8.7%. [Mo(O)(CN)₄(MeCN)](PH₃)₂N]₂ belongs to triclinic space group P-1 witha=13.770(4)Å,b=16.292(5)Å,c=16.889(5)Å, =73.23(2)°, =72.02(2)° and =71.57(2)°. The volume of the unit cell is 3342(3)ų withz=2. The structure was refined to R=7.2%.     

Verfeinerung der Kristallstruktur von Kupfer(II)-hydroxichlorid,Cu(OH)Cl

The crystal structure of Cu(OH)Cl [a=5.555 (2) Å,b=6.671 (4) Å,c=6.127 (2) Å, =114.88 (3)°, space group P2_I/a,Z=4] was refined for 810 observed reflections with sin /0.80 Å^–1 toR=0.035. Crystals were synthesized under hydrothermal conditions. The copper atom is planar four coordinated by three oxygen atoms and one chlorine atom; two further chlorine atoms complete its coordination. The copper polyhedra share edges to build up sheets, which are connected by hydrogen bonds to the chlorine atoms of adjacent sheets.

     

Copper(II) complexes of schiff bases derived of 2-hydroxy-3-naphthaldehyde. The crystal and molecular structures of bis-{(phenyl)[(2-oxo-3H-naphth-3-ylidene)methyl]aminato}copper(II) and bis-{(benzene-4-trifluoromethyl)[(2-oxo-3H-naphth-3-ylidene)-methyl]aminato}copper(II)

Summary The Schiff base ligands, 3-[(Phenyl)-2-hydroxy-3H-Naphth-3-ylidene)methyl]aldamine (1) and 3-[(benzene-4-trifluoromethyl)-2-hydroxy-3H-naphth-3-ylidene)methyl]aldamine (2), and their corresponding Cu(II) complexes (I andII were synthesized. The crystal and molecular structures ofI andII were determined. CompoundI crystallizes in the triclinic crystal systema=10.804(5),b=12.589(5), andc=10.369(3) (Å), =107.72(3), =95.75(3), and =76.32(4)(°), in the space group P withZ=2. CompoundII crystallizes in the triclinic crystal systema=10.718(2),b=13.861(4), andc=10.110(9) (Å), =95.99(2), =90.16(2), and =93.90(2)(°), in the space group P withZ=2. The geometry around the metal atom in both complexesI andII is square planar.

---

Kupfer(II)-Komplexe von Schiffbasen von 2-Hydroxy-3-naphthaldehyd. Die Kristall-und Molekülstrukturen von Bis{(phenyl)[(2-oxo-3H-naphth-3-yliden)methyl]aminato}kupfer(II) und Bis{(benzen-4-trifluoromethyl)[(2-oxo-3H-naphth-3-yliden)methyl]aminato}kupfer(II)

Zusammenfassung Es wurden die Schiffbasen-Liganden 3-[(Phenyl)-2-hydroxy-3H-naphth-3-yliden)-methyl]aldamin (1) und 3-[(Benzen-4-trifluoromethyl)-2-hydroxy-3H-naphth-3-yliden)-methyl]aldamin (2) inklusive der entsprechenden Kupfer(II)-KomplexeI undII dargestellt. VonI undII wurden die Kristallstrukturen ermittelt. KomplexI kristallisiert im triklinen System mita=10.804(5),b=12.589(5),c=10.369(3) Å, =107.72(3), =95.75(3) und =76.32(4)° in der Raumgruppe P mitZ=2. VerbindungII kristallisiert ebenfalls im triklinen System mita=10.718(2),b=13.861(4),c=10.110(9) Å, =95.99(2), =90.16(2) und =93.90(2)° in der Raumgruppe P mitZ=2. Die Geometrie rund um Cu ist in beiden Komplexen quadratisch-planar.

     

IR-spectroscopic studies of strength and concentration of acid centers on V2O5/Al2O3 catalysts

The strength of protonic sites and the concentration of acid centers in V₂O₅/Al₂O₃ catalysts have been estimated according to pyridine and ammonium adsorption.

---

V₂O₅/Al₂O₃.

     

Thermogravimetry of copper and copper oxides (Cu2O-CuO)

The thermogravimetry of mixtures of metallic copper and copper oxides was studied. The experiments were performed by heating the samples in air to 700–800° to transform all the components to copper(II) oxide, and continuing the heating in nitrogen to 1050–1100° when the dissociation of copper(II) oxide to copper(I) oxide is complete. The identification of the components and their quantitative determination were carried out by determining the shape, size, and ratio of the segments of the curves obtained during the heating. The method can be used for quantitative analysis of mixtures of copper and/or copper oxides.

---

Zusammenfassung Gemische von metallischem Kupfer und Kupferoxiden wurden thermogravimetrisch untersucht. Zur Überführung aller Komponenten in Kupfer(II)-oxid erhitzte man sie in Luft auf 700–800°, um daraufhin bis zur vollständigen Dissoziation des Kupfer-(II)-oxids zu Kupfer(I)-oxid unter Stickstoff die Temperatur bis auf 1050–1100° zu steigern. Die Identifizierung der Komponenten und ihre quantitative Bestimmung erfolgten durch die Form, Größe und die Verhältnisse der verschiedenen Abschnitte der erhaltenen Kurven. Diese Methode ist zur quantitativen Bestimmung von Gemischen aus Kupfer und Kupferoxid sowie von Kupferoxiden geeignet.

---

Résumé Étude thermogravimétrique de mélanges du cuivre métallique et d'oxydes de cuivre. Les échantillons sont d'abord chauffés dans l'air jusqu'à 700–800° jusqu'à ce que tous les constituants soient transformés en oxyde de cuivre(II); le chauffage est ensuite poursuivi dans l'azote jusqu'à 1010–1100°, où la dissociation de l'oxyde de cuivre(II) en oxyde de cuivre(I) est complète. Les constituants ont été identifiés et dosés en utilisant la forme, la dimension et les proportions des différentes parties des courbes pendant le chauffage. La méthode peut être utilisée pour l'analyse quantitative de mélanges de cuivre et ou d'oxydes de cuivre.

---

. 700–800: ( (), 1050–1100° [ () (I)]. , , . / .

---

---

The author wishes to acknowledge the financial assistance provided by the Technion — Israel Institute of Technology.The author wishes also to thank Dr. R. F. Tylecote (University of Newcastle Upon Tyne, England) for very helpful comments and useful discussions of this investigation and to Mrs. N. Leder for chemical analyses.     

Energy dissipation and selectivity in the catalytic oxidation of ammonia

A qualitative interpretation of selectivity changes in ammonia oxidation, based on considerations of energy dissipation processes is presented.

---

, .

     

Endo and Exo Coordination to Cofacial Binuclear Copper(II) Complexes

A structural study of internal (endo) and external (exo) coordination to cofacial binuclear complexes is reported.Cu₂(NBA)₂(NBAH₂=3,3'-[2,7-naphthalenediylbis(methylene)]-bis(2,4-pentanedione)) is large enough to accommodate 2-methylpyrazine as an intramolecularly coordinated guest molecule Cu₂(NBA)₂((2Mepyz))4CH₂Cl₂Cu₂C₅₃H₅₈N₂O₈Cl₈, orthorhombic, space group Pnma (No. 62); a = 22.4674(11); b = 22.230(2); c = 11.4520(6) Å V = 5719.6(6) ų (at 100 K); Z = 4; R = 0.058; R _w = 0.167 for 344 parameters and 5339 reflections with I > 2(I). The Cu₂(NBA)₂(-(2-Mepyz)) molecules possess crystallographic m symmetry, with the CuCu vector (CuCu' 7.4801(8) Å) perpendicular to the mirror plane; this requires disorder in the 2-Mepyz guests. The two ``Cu(acac)₂' moieties (acacH = 2,4-pentanedione) are not quite parallel (dihedral angle between (acac)₂ planes = 3.93(7)^circ), forming a slightly wider opening on the side of the methyl group in the 2-Mepyz guest. On the other hand, the cavity in Cu₂(XBA)₂ (XBAH₂ = 3,3'-[1,3-phenylenebis(methylene)]-bis(2,4-pentanedione)) is smaller, so that CH₃CN must bind externally.Cu₂(XBA)₂(CH₃CN)₂1.5CH₃CNH₂O,Cu₂C₄₃H_52.5N_3.5O₉, monoclinic, space group P2₁/c (No. 14); a = 11.7361(16); b = 14.197(3); c = 13.299(3) Å; = 92.22(2)^{^}; V = 2214.3(7) ų (at 100 K); Z = 2; R = 0.044; R _w = 0.124 for 275 parameters and 4983 reflections with I > 2 (I). This structure contains centrosymmetric Cu₂(XBA)₂ units (CuCu' 4.8302(12) Å) with externally coordinated CH₃CN ligands. The crystal packing in Cu₂(NBA)₂((2Mepyz))4CH₂Cl₂,which contains close contacts between layers of Cu₂(NBA)₂(-(2-Mepyz)) moieties, is also similar to that in three other crystalline host–guest adducts M₂(NBA)₂(-G). Cu₂(XBA)₂(CH₃CN)₂1.5CH₃-CNH₂O does not contain similar layers of molecules, presumably because the adduct molecules do not have the same type of exposed flat surfaces.     

Polarographic investigation of the Cu(II) complex with ampicillin

The complex of Cu(II) ion and ampicillin is investigated polarographically in aqueous medium, at pH = 6, an ionic strength = 0.2, and room temperature. The stoichiometric ratio of Cu(II) and ampicillin in the complex, and the stability constant, logK = 5.1, were determined by Lingane's method.     

Preparation and structure of cobalt(II), nickel(II), copper(II) and zinc(II) complexes with 3-amino-5-(α/β)pyridyl-1, 2, 4-triazoles

Summary Complexes of bidentate 3-amino-5-()-pyridyl-1,2,4-triazole (L¹) and 3-amino-5-()-pyridyl-1, 2, 4-triazole (L²) of composition [ML¹Cl₂·H₂O], [ML²Cl₂·H₂O], [ML ₃ ^2/1 Cl₂] and [ML ₃ ^2/2 Cl₂] [M=Co^II, Ni^II, Cu^II, M=Zn^II] have been prepared and characterized by elemental analyses, i.r., u.v./visible, e.s.r. spectra, magnetic moments and molar conductances.     

Crystal structure of the 1:2 molecular complex between thecis-anti-cis isomer of dicyclohexano-18-crown-6 and 3-chloro-6-methylbenzenesulphamide

Reaction of thecis-anti-cis isomer of dicyclohexano-18-crown-6 with a mixture of 2-chloro-5-methylbenzenesulphamide and 3-chloro-6-methylbenzenesulphamide gives a crystalline product which has been characterized using X-ray crystallography. The complex (I) contains both isomers in a 83.0 (0.6):17.0 (0.6) ratio in favour of the 3-chloro-6-methyl-isomer. The joint crystallization of the crown ether with the mixture of the guest isomers might serve as a route for the partial extraction of one of them. The complex with host: guest ratio 1:2 crystallizes in a triclinic space group ,a=13.087(4),b=9.217(2),c=8.120(2) Å, =92.05(3),=100.52(3), =80.64(2)°, withZ=1. The structure was refined toR=0.041. Each of two equivalent guest molecules interacts with the macrocyclic ring by two NH...O hydrogen bonds, with N...O distances of 2.912(5) and 3.040(5) Å. Supplementary Data relevant to this paper have been deposited with the British Libary as Supplementary Publication No. SUP 82180 (30 pp.).     

Kinetic model for methanol conversion over Mg-ZSM-5 zeolite

The catalytic conversion of methanol to olefins over ZSM-5 zeolite modified by ion exchange with Mg exhibits an autocatalytic character. On this basis an overall kinetic model of the reaction was proposed which allowed the determination of rate constants and apparent activation energy.

---

ZSM-5, Mg, . , .

     

Empirical equations of state for adsorption layer: Alkylthiopolyoxyethylene glycols

Surface tension isotherms ofn-alkylthiopolyoxyerhylene glycols:n-C _x H_2x+1S(CH₂CH₂O) _y H, wherex=5 to 8,y=3 or 4, were approximated with orthogonal polynomials to get good quality values of surface pressure (II) and molar area of the adsorbed layer (). The modified Volmer (*(–₀)=Z*R*T) van der Waals and virial equations of state were used to correlate and in terms of real two-dimensional gas. The combination of Volmer and van der Waals equations of state made it possible to determine the interaction energy, , which was prescribed to cohesion of hydrophobic chains in the adsorption layer. The value of for the amphiphiles in question was in the range 0.97–1.91R*T and the average contribution per methylene group was ca. 0.21R*T.The Lennard-Jones potentials calculated from second virial coefficient were of the same range as , but no clear relation was found between their values and number of structure elements of the alkylthiopolyoxyethlene glycols.Presented during 7th International Conference: Surface and Colloid Science, July 7–13, 1991, Compiegne, France     

Structure électronique de l'o-benzoquinone (méthode L.C.A.O. améliorée)

Résumé La théorie L. C. A. O. améliorée est appliquée à l'étude de la structure électronique de l'o-benzoquinone. Les indices de liaison obtenus conduisent aux distances interatomiques suivantes: 1,23 Å pour les groupements carbonyles, 1,46 Å pour les liaisons «simples», 1,35 Å pour les liaisons «doubles». Les résultats obtenus pour l'énergie des transitions N V et N A et pour le moment dipolaire sont en bon accord avec l'expérience.

---

The improved LCAO theory is applied to o-benzoquinone. The mobile bond orders give the following bond distances: 1,23 Å for the C=O bonds, 1,35 Å for the double bonds, 1,46 Å for the single bonds. The results we got for the N V and N A transition energies, and for the dipole moment are in good agreement with the experiment.

---

Zusammenfassung Die elektronische Struktur der o-Benzochinon-Molekel wird mit Hilfe der verbesserten LCAO-Methode untersucht. Die berechneten Bindungsindices geben die folgenden interatomaren Abstände: 1,23 Å für die C=O-Bindungen, 1,46 Å für die Einfachbindungen, 1,35 Å für die Doppelbindungen. Die Werte für die N V- und N A-Übergänge und für das Dipolmoment stimmen gut mit der Erfahrung überein.