Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint-Viallard Conductivity Equation. Part 1. Symmetrical 2:2 Type Electrolytes. Dilute Aqueous Solutions of Alkaline Earth Metal Sulfates and Transition Metal Sulfates

Literature values of the electrical conductivities of dilute aqueous solutions of alkaline metal sulfates (BeSO₄, MgSO₄, CaSO₄, SrSO₄) and of transition metal sulfates (MnSO₄, FeSO₄, CoSO₄, NiSO₄, CuSO₄, ZnSO₄, CdSO₄) were reexamined within the framework of the Quint-Viallard conductivity equations in order to obtain a uniform representation of conductivities. It was observed that the limiting conductances of electrolytes at infinite dilution are very similar irrespective of the applied conductivity equation, whereas the derived ion association equilibrium constants vary considerably. The ion association equilibrium constants are therefore of doubtful physical value and should be treated rather as just fitting parameters.     

Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint-Viallard Conductivity Equation. Part 2. Symmetrical 3:3 Type Electrolytes. Dilute Aqueous Solutions of Rare Earth Hexacyanoferrates(III) and Hexacyanocobaltates(III)

Literature values of the electrical conductivities of dilute aqueous solutions of trivalent rare earth hexacyanoferrates(III) (La, Pr, Nd, Sm, Gd) and of rare earth hexacyanocobaltates(III) (La, Nd, Sm, Y) were reexamined within the framework of the Quint-Viallard conductivity equation in order to obtain a uniform representation of their conductivities. It was observed that the limiting conductances of electrolytes at infinite dilution depend weakly on the applied conductivity equation, whereas the derived ion association equilibrium constants vary considerably and therefore should be treated rather as fitting parameters.     

Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint-Viallard Conductivity Equation. Part 4. Symmetrical 2:2, 3:3 and Unsymmetrical 2:1, 3:1 and 1:3 Type Electrolytes in Pure Organic Solvents

Conductivities of symmetrical and unsymmetrical electrolytes of 2:2, 3:3, 2:1, 3:1 and 1:3 charge types in pure organic solvents (methanol, ethanol, 1-propanol, dimethyl sulfoxide, acetonitrile, formamide, N-methylformamide, N,N-dimethylformamide, N-methylacetamide and N,N-dimethylacetamide) were analyzed using the Quint-Viallard conductivity equation and taking into account the ion association effect. The molar limiting conductances and the ion association constants were determined for various multivalent electrolytes in these solvents using the literature conductivities. In many cases, for the first time, it was possible to obtain consistent values of the limiting ionic conductances in organic solvents.     

Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint-Viallard Conductivity Equation. Universal Curves of Limiting Conductances and Walden Products of Electrolytes in Mixed Solvents. Part 5. Symmetrical 2:2, 3:3 and Unsymmetrical 1:2, 2:1 and 1:3 Type Electrolytes

Conductivities of symmetrical and unsymmetrical electrolytes of 2:2, 3:3, 1:2, 2:1 and 1:3 types in ethanol–water and the 1,4-dioxane–water mixtures were analyzed using the Quint-Viallard conductivity equation and taking into account the ion association effect. The molar limiting conductances and the ion association constants were reexamined for various multivalent electrolytes. One non-aqueous system, methanol–ethylene glycol mixtures, was also considered. The limiting conductances were also examined in the framework of universal curves of limiting conductances and the excess Walden products introduced by the author. These new concepts in the analysis of conductance data allow the estimation of values of limiting conductances of electrolytes or ions, to give an indication about the quality of the conductivity measurements and the type of interactions expected in the systems. It was found that for any type of electrolyte only one universal curve of limiting conductances exists. In the water-rich mixtures, attractive interactions (structure-making effects) are expected when electrolytes are added to mixtures with ethanol or with 1,4-dioxane. In contrast, in ethylene glycol–methanol-rich mixtures repulsive interactions (structure-breaking effects) are more likely.     

Activity Coefficients of Electrolytes from Liquid Membrane Cells. XI. The Nonsulfate 1:2 Salts,Potassium Oxalate,and Sodium 1,5-Naphthalenedisulfonate

Activity coefficients of K₂C₂O₄ and Na₂ds, ds^2– = 1,5-naphthalenedisulfonate anion, which were previously unavailable, are examined at 25.0°C using liquid membrane cells. The results for both salts are approximated satisfactorily by the primitive model in spite of the fact that ds^2–, a planar ion with electric charges distant from one another, does not resemble a charged hard sphere. Data are compared with those of K₂SO₄ and bivalent metal perchlorates. The Pitzer ion-interaction parameters are reported.     

6′，6″-二吡啶基-2，2′：4′，4″：2″，2′′′-四联吡啶稀土配合物的合成、表征及荧光性质研究(英)

Two series of solid complexes of rare earth nitrates and picrates with the “back-to-back” terpyridine, 6′,6″-bis(2-pyridyl)-2,2′:4′,4″:2″,2′′′-quaterpyridine (L) have been synthesized. These complexes have been characterized by elemental analysis, conductivity measurements, thermal analysis and IR spectroscopy. At the same time, the luminescent properties of the Eu(Ⅲ) and Tb(Ⅲ) complexes were also studied.     

2,6—双（1′—苯基—3′—甲基—5′—氧代—4′—甲酰吡唑）吡啶稀土配合物的合成

在乙醇－水溶液中合成了１４种２，６－双（１′－苯基－３′－甲基－５′－氧代－４′－甲酰吡啶）吡啶稀土配合物，元素分析确定其化学组成的ＲＥ２Ｌ３．ｎＨ２Ｏ并用紫外可见光谱、红外光谱，核磁共振谱，热分析，荧光光谱，摩尔电导等进行了表征。     

ChemInform Abstract: Crystal Structures of New Ternary Rare Earth Silicides Sc3Pr2Si4, Sc1.26Pr3.74Si4 and Sc3.96Nd1.04Si4 with Ordered and Partially Ordered Rare Earth Sites.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Synthesis,Crystal Structure,and Conductivity Investigation of a New Monophosphate: (2-CH3OC6H4CH2NH 3)H2PO4

Chemical preparation, crystal structure, thermogravimetric and differential analysis, solid state ³¹P MAS NMR characterization, and IR spectroscopic investigations are given for a new organic cation dihydrogenmonophosphate, (2-CH₃OC₆H₄CH₂NH₃)H₂PO₄. This compound is monoclinic C2/c, with unit cell parameters a = 27.740(8), b = 4.827(2), c = 16.435(3) Å, β = 93.79(2)°, V = 2196 (1) ų, Z = 8, and ρ = 1.422 g · cm^?3. The crystal structure has been determined and refined to R = 0.046 (Rw = 0.056), using 1,746 independent reflections with I > 3σ (I). Its atomic arrangement can be described by infinite polyanions [H₂PO₄] _n ^{n ?}, organized in ribbons alternating with organic cations. Strong hydrogen bonds connect the different components. Electrical conductivity measurements show that the [2-CH₃OC₆H₄CH₂NH₃]H₂PO₄ has a low ionic conductivity value at 403 K.     

Hetero-Diels-Alder Additions of α,β-Unsaturated-Acyl Cyanides. Part 3. Syntheses of 3-bromo-2-ethoxy-3,4-dihydro-2H-pyran-6-carbonitriles,and about their transformation to 2-ethoxy-2H-pyrans

Cycloadditions of the α,β-unsaturated-acyl cyanides 1–3 with (Z)-or (E)-1-bromo-2-ethoxyethene ( 4 ) may be performed at moderate temperatures and provide in good yields the 3-bromo-2-ethoxy-3,4-dihydro-2H-pyran-6-carbonitriles 5–7 , respectively (Scheme 1). Diastereoisomeric pairs of products result at room temperature merely from the ‘endo’- and ‘exo’-transition states; more complex mixtures appear above 60° as a consequence of (Z)/(E)-isomerization of 4 . The relative stability of the anomers of 5 and 6 is explored by treatment with BF₃·Et₂O. Acid alcoholysis (MeOH or EtOH) of 5 leads to acetals 9a , b of 4-bromo-5-oxopentanoate. Alkyl (2Z,4E)-5-ethoxypenta-2,4-dienoates 12 , 17 , and 20 , are formed in alcoholic alkoxide solutions from 5 , 6 , and 7 , respectively, which is compatible with the intermediacy of 2-alkoxy-2H-pyrans and their valence tautomers, α,β-unsaturatedacyl cyanides. Methoxide addition to the CN group competes with dehydrobromination in case of 5 ; it leads to 3-bromo-3,4-dihydro-2H-pyran-6-carboximidate 13 (ca. 50% at ?20°) which can be hydrolyzed to the methyl carboxylate 14 . DBU (1,8-diazabicyclo[5,4,0]undec-7-ene) in benzene converts 5 to 6-ethoxy-2-oxohexa-3,5-dienenitrile ( 11 ), the ring-opening product of an obviously unstable 2-ethoxy-2H-pyran; the same reagent dehydrobrominates 6 to 2-ethoxy-4-methyl-2H-pyran-6-carbonitrile ( 15 ). HBr Elimination from 7 takes place with great ease in presence of pyridine, or even during chromatography on alumina, and leads to the stable ethyl 6-cyano-2-ethoxy-2H-pyran-4-carboxylate ( 18 ); this dimerizes at room temperature to give a 1:3 mixture of tricyclic adducts ‘endo’- 21 and ‘exo’- 21 . The structure of the latter is established by an X-ray crystallographic analysis.     

Rac. cis- und trans- 1, 2-Dimethyl-4-hydroxy-6, 7-dimethoxy-1, 2, 3, 4-tetrahydro-isochinolin,Synthese und Stereochemie

The synthesis of rac. cis- and trans-1,2-dimethyl-4-hydroxy-6,7-dimethoxy-1,2,3,4-tetrahydro-isoquinoline (respectively 8 and 9 ) is described. The relative configuration of these amino alcohols was determined by a detailed analysis of nmr.- and ir.-spectra. The comparison of the nmr.-spectra of 8 and 9 with that of gigantine reveals the non identity of these compounds.     

Structural Study of Alkaline 1-Phenyl-1H-1, 2, 3, 4-tetrazole-5-thiolate Salts: An Example of Periodicity in Alkaline Cations

The alkaline 1-phenyl-1H-1, 2, 3, 4-tetrazole-5-thiolate salts, M[C₆H₅N₄CS] (M = Li ( 1 ), Na ( 2 ), K ( 3 ), Rb ( 4 ) and Cs ( 5 )) were obtained and characterized by means of mass spectrometry (FAB⁺) and NMR (¹H; ¹³C) spectroscopy. The structures of Na ( 2 ), K ( 3 ), Rb ( 4 ) and Cs ( 5 ) compounds were determined by X-ray diffraction methods. The ligand shows a rich variety of coordination patterns with the alkaline cations. The formation of a four-membered ring MSCN in the compounds with heavier alkali cations (K, Rb and Cs) is shown. In all the cations the coordination number around it increases with the ionic radius. Compounds with Cs⁺ and Rb⁺ exhibited the formation of Cs-C and Rb-C interactions with the phenyl group.     

Cyclic Acetal-Photosensitized Polymerization. IV. Photopolymerization of Styrene in the Presence of 1, 3:2, 4:5, 6-Trimethylene-D-Sorbitol

Styrene(St) was polymerized in benzene solution in the presence of l, 3:2, 4:5, 6-trimethylene-D-sorbitol(TCA) by means of photo-irradiation of system at 30°C. It was found that the polymerization was depressed by the addition of TCA and then proceeded through a radical mechanism. The chain-transfer constant of the styryl radical to TCA was estimated to be 0.16. Accordingly, the photopolymerization of St in the presence of TCA is studied kinetically with regard to chain transfer and termination.     

The Inorganic-free Organic Conductor α''''-(ET)_2C_6H_4(SO_3)_2 : Its Synthesis, Structure, and Conductivity

Having more than twenty years?glory, ET series still keep the most promising family in various kinds of organic conductors. Most of ET based molecular conductors consist of organic cationic ET+0.5 radical and certain anionic inorganic component such as the superconductor k-(ET)2Cu[N(CN)2]Cl (TC = 12.8K, 0.3kbar)1. Recently, the first purely organic superconductor b-(ET)2SF5CH2CF2SO3 (TC = 5.2K)2 has been reported, which aroused our interest on this kind of inorganic-free organic c…     

Synthesis of Novel Nucleoside: 2'-deoxyuridine-3',5'-di(4, 4'-dimethoxy-5, 6, 5', 6'-dimethylenedioxybipheny1-2-methoxy carbonyl 2'-carboxylate)

Anumberofnucleosideshavebeenreportedtobeanti-hepatitisBvirusagents',althoughnoneofthemhaveyetbeenprovedtobeclinicallyusefull.Inaddition,dimethyldicarboxylatebiphenyl(DDB)isawidelyusedanti-hepatiticdrugwithhigheffectinloweringSGPTandconsiderablelowtoxicity'.InviewofthediscoverythatseveralnucleosideswiththeD-configurationandanaloguesofthebiphenyldicarboxylateareselectiveantiviralagents,itwasofinteresttosynthesizenucleosidederivativesaspotentialantiviralagents.Recently,thecarbocyclicanalogueo…     

A new fused heterocyclic system: 6H-pyrazolo[3, 4-c][1, 2, 5]thiadiazine 2, 2-dioxide

A base-promoted cyclodehydration of 4-nitroso-5-alkylsulfonylamidopyrazoles 3 afforded 6H-pyrazolo-[3, 4-c][1, 2, 5]thiadiazine 2, 2-dioxide ( 4 ). The structure of 4 was confirmed through X-ray analysis.     

Die massenspektrometrische retro-Diels-Alder-Reaktion: 1, 2, 3, 4-Tetrahydroisochinolin und 1, 2, 3, 4-Tetrahydronaphthalin (Tetralin). 31. Mitteilung über massenspektrometrische Untersuchungen

The Mass Spectral retro-Diels-Alder-Reaction: 1,2,3,4-Tetrahydroisoquinoline and 1,2,3,4-Tetrahydronaphthaline (Tetraline) The retro-Diels-Alder reaction of 1,2,3,4-tetrahydroisoquinoline and of its N-acetyl derivative was confirmed on the basis of labelled derivatives (Scheme 2). Furthermore, the loss of ethylene was investigated with the 1,2,3,4-tetrahydronaphthalene- and 1,2,3,4-tetrahydronaphthalen-1-one-derivatives given in Schemes 4, 5 and 6. In the case of the 1,2,3,4-tetrahydronaphthalen-1-one-derivatives ethylene is lost via a retro-Diels-Alder reaction. The loss of ethylene from 1,2,3,4-tetrahydronaphthalene ( 1 ) and from its derivatives is a rather complex reaction (Scheme 8): 1/3 of ethylene is split off 1 ⁺ via a formal retro-Diels-Alder reaction, 2/3 are lost after a specific rearrangement. The ratio of these two fragmentation pathways depends very much on the substituents placed at the aliphatic and the aromatic rings, compare e.g. Table 4.