Über Chrom(II)-carboxylate und Halogenochromate(II)

Highly pure chromium(II) acetate, was obtained from chromium powder and anhydrous acetic acid in the presence of a small amount of acetylhalide. Cr^II acetate reacts with acetyl halide in anhydrous acetic acid to sesquisolvates like CrCl₂ · 3/2 CH₃COOH. If one equivalent of alkali acetate or an organic nitrogen base is added to solutions of Cr^II acetate in acetyl halide/acetic acid mixtures, trihalochromates(II) are precipitated which are hexagonal in structure, except the ammonium and the potassium salt. With two equivalents of alkali or ammonium acetate tetrachlorochromates(II) of cesium, rubidium and ammonium are precipitated. They are tetragonal in structure (K₂NiF₄ type). Using pyridinium acetate with various mixtures of acetyl bromide and acetic acid, only the solvates (PyH)₃(CrBr₅) · 2CH₃COOH is formed.     

Über Blei (II)-oxidhydrat der Zusammensetzung 3PbO·H2O

Lead oxide hydrate mentioned in the earlier literature with several formulas between PbO · H₂O and PbO · 0.33 H₂O has been synthesized and investigated by high resolution X-ray powder methods, thermogravimetry and infrared spectroscopy. The unit cell was found from 62 powder reflections to be tetragonal with a = 8.009 ± 0.003 Å, c = 9.312 ± 0.005 Å, Z = 12 [PbO · 0.33 H₂O]. These data were confirmed by WEISSENBERG and Precession photographs of single crystals grown as a corrosion product on metallic lead. The space group is D–P4/mnc or C–P4 nc. Thermogravimetric measurements, corrected for a slight content of superficially bound carbon dioxide detected by infrared spectroscopy, lead to the most probable formula 3 PbO · H₂O or PbO · 0.33 H₂O. As infrared spectra show the presence of a HOH deformation vibration, the compound is considered to be an oxide hydrate and not an oxide hydroxide of lead.     

Über Blei(II)-oxid- und -hydroxidchloride

Inhaltsübersicht. Bei der Reaktion von tetragonalem Blei(II)-oxid in wäßriger Suspension mit Calciumchlorid oder mit Ammoniumchlorid lassen sich für molare Verhältnisse Cl^–/PbO bis zu 4/1 nur drei kristalline basische Blei(II)-chloride in der festen Phase mit den Pb/Cl-Verhältnissen von 3,5, 2,0 bzw. 1,0 nachweisen. Lead(II) Oxide and Hydroxide Chloride Abstract. In the reaction between tetragonal lead(II) oxide in aqueous suspension and calcium chloride, or ammonium chloride, and for molar ratios of Cl^–/PbO up to 4/1 only three kinds of crystalline basic lead chlorides are detectable in the solid phase with Pb/Cl ratios of 3.5, 2.0 and 1.0, respectively.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. XL. Über Lithium-alkenylmanganate(II)

Contributions to the Chemistry of Transition Metal Alkyl Compounds. XL. About Lithium Alkenylmanganates(II) MnCl₂ reacts with vinyl, 2,2-dimethylvinyl, allyl, and methallyl lithium giving rise to alkenyl manganates(II). In a pure state the compounds Li₂[Mn(CH?CH₂)₄] · 1.5 diox, Li₂[Mn(CH?C(CH₃)₂)₄] · 1.5 diox, Li₂[Mn(CH₂? CH?CH₂)₄] · 2.5 diox and Li₃[Mn(CH₂? C(CH₃)?CH₂)₅] · 2 diox were isolated. The compounds were characterized by elementary analysis, EPR and IR spectra, magnetic moments, and reactions with iodine.     

Über Kaliumtetracyanoplatinat(II), Kaliumtetracyanopalladat(II) und deren Monohydrate

We have determined the crystal structures of the potassium tetracyanoplatinates(II) and ‐palladates(II), and of their monohydrates, by X‐ray powder diffraction techniques and single crystal structure analysis. K₂[Pt(CN)₄]: orthorhombic; Pccn; a = 1370.11(2); b = 907.09(1); c = 703.91(2) pm; Z = 4; R_F² = 0.0903 (N(hkl) = 415). K₂[Pt(CN)₄] · H₂O: orthorhombic; Pnna; a = 715.79(4); b = 977.91(6); c = 1322.46(8) pm; Z = 4; R(F)_N′ = 0.027 (N′(hkl) = 1066). K₂[Pd(CN)₄]: monoclinic; P2₁/c; a = 433.03(2); b = 782.90(3); c = 1328.17(6) pm; ß = 93.069(3)°; Z = 2; R_p = 0.0583 (N(hkl) = 352). K₂[Pd(CN)₄] · H₂O: orthorhombic; Pnna; a = 721.48(6); b = 976.77(8); c = 1326.4(1) pm; Z = 4; R(F)_N′ = 0.048 (N′(hkl) = 1137). In all examined representatives the anions are stacked one upon the other, even though they are tilted in part. The results are completed by spectroscopic and thermo analytical investigations.     

Über Alkalihexafluorobismutate(V)

The compounds LiBiF₆ (a = 5.18, c = 13.9₉ Å), NaBiF₆ (a = 5.47, c = 15.1₆ Å), RbBiF₆ (a = 7.71, c = 7.89 Å) and CsBiF₆ (a = 7.93, c = 8.27 Å, hexagonal lattice constants) are rhombohedral. The hexagonal unit cell contains three formula weights. LiBiF₆ and NaBiF₆ are isotypic with LiSbF₆, RbBiF₆ and CsBiF₆ are KOsF₆-isotypes. All compounds are colourless and very moisture sensitive.     

Über den Mechanismus der Cope-Umlagerung

On the Mechanism of the Cope Rearrangement The rates of the Cope rearrangement of 2,5-dicyano-3-methyl-hexa-1, 5-diene ( 12 ), (E)- and (Z)-2, 5-dicyano-hepta-1,5-diene ((E)- and (Z)- 14 ) as well as of 2, 5-dimethoxycarbonyl-3-methyl-hexa-1,5-diene ( 13 ) and (E)- and (Z)-2,5-dimethoxycarbonyl-hepta-1,5-diene ((E)- and (Z)- 15 ) were measured in decane solution in the temperature range of 50 to 150° (see Tables 5 and 8 to 12). A detailed English summary of this work is given in [1 b].     

Über Halogenotitanate(IV)

The preparation of tetraethylammonium slats with following anions is described: [TiBrCl₅]^2?,[TiBr₅Cl]^2?,[TiCl₄Br · CH₃CN]^?, [TiBr₄Cl · CH₃CN]^?, [TiBr₅ · CH₃CN]^? und TiF. The reaction mechanisms is discussed. TiF forms fluorine-bridges giving a polymeric anion. Chlorofluorotitanates(IV) could not be prepared. Mixed halide complexes of Ti(IV), Nb(V) and Ta(V) are compared with analogous complexes of Sn(IV), Pb(IV) and Sb(V).     

Über die Struktur von Bis-(dihydroxoboroxalendiamiddioximato)-nickel(II)-tetrahydrat

The space group of the sparingly soluble brown coloured bis-(dihydroxobor-oxalene-diamide-dioximato)-nickel(II)-tetrahydrate (C₄H₁₂N₈O₈B₂Ni · 4 H₂O) is P21/c with a = 9.25, b = 13.27, c = 6.61 Å and β = 92.7°. The structure was solved on single crystals. There are two molecules in the unit cell. Within the square planar complex the nickel atom is bonded to the four nitrogen atoms of the plane system of the two dioximato ligands (Ni? N = 1.84 ± 0.02 Å). Each of the boron atoms is tetrahedrally surrounded by two oxygen atoms belonging to the oxime groups and two hydroxyl groups (B? O = 1.50 ± 0.06 Å). Thus the complex has the conformation of a chair form. The water molecules participate in intermolecular hydrogen bonds. There is no interaction between Ni atoms.     

Über die Stereochemie von Zwischenprodukten (Aldolbasen) der Doebner-von Miller-Chinolin-Synthese

In the Doebner-von Miller quinoline synthesis with acetaldehyde or crotonaldehyde two stereoisomeric 4-hydroxy-1, 2, 3, 4-tetrahydroquinaldines are formed as intermediates. The stereochemistry of these compounds differing in the relative positions of the hydroxygroups to the methyl-group can be ascertained by NMR.-spectroscopy. The pK_a-values of stereoisomers are not identical due to the different spacial positions of the HO-groups.     

Über Halogenphenylester der Phosphorsäure

A simple method for preparing halogenphenylesters of phosphoric, phenylphosphonic and phosphorous acid from the respective acid chlorides and phenols in the presence of various nitrogen-containing catalysts is described. Contrary to other methods, these reactions give high yields, despite of steric hindrance.     

Über die Hydrolyse von Eisen(III)-Salz-Lösungen. II Die Alterung der Hydrolyseprodukte

On the Hydrolysis of Iron (III) Salt Solutions. II. Ageing of Hydrolysis Products The long time ageing up to 15 years of the products obtained by alkalifying iron(III) chloride solutions to different neutralisation degrees has been studied. The concentration of the Fe³⁺ and the Cl- ions, the strength of the alkali, and the rate of its addition influence the results. Slow alkalifying produced up to 90% neutralisation β-FeOOH. The transformation of the amorphous iron(III) oxidehydroxide to β-FeOOH was promoted by a high concentration of the Cl- ions. When a large amount of amorphous iron(III) oxidehydroxide was formed, intimately intergrown crystals of α- and β-FeOOH resulted. On further ageing β-FeOOH transformed into α-FeOOH. At a degree of neutralisation of 95 and 100% transformation of the amorphous iron(III) oxidehydroxide into α-Fe₂O₃ occurred. The 100% neutralized precipitate, however, remained partly amorphous. Authors discuss the factors that determine very slow reactions leading to these results.     

Über die absolute Konfiguration der Visnagane

(+)-cis-Khellactone methyl ether ( 4 ) and (?)-trans-khellactone methyl ether ( 6 ) had earlier been assigned the absolute configurations 3′-S; 4′-S and 3′-S; 4′-R, respectively, on the basis of the FREUDENBERG , rule. Both compounds together with their defunctionalised derivatives (?)- 7 and (+)- 8 (=(+)-lomatin), obtained from a mixture of (+)-visnadin ( 1 ) and (+)-samidin ( 2 ), were investigated by the HOREAU method. A conformational analytical study showed that the optical yield should rise in the order 4 < 6 < 7 , 8. This order was found and the α-phenylbutyric acid liberated was always dextrorotatory. The centre 3′ of the khellactones and their derivatives must be R-chiral and not S. Treatment of (?)- 6 with pyridinium perbromide gave (?)-trans-3-bromokhellactone methyl ether ( 11 ) as orthorhombic crystals. The X-ray crystal structure determination was made using the anomalous scattering of the Mo-K α radiation by Br. The result, — centre 3′ R-chiral (fig. g) — showed that the HOREAU method was correct.     

Über neue Hexafluoroaluminate(III)

On New Hexafluoroaluminates (III) Due to Guinier-Simon powder photographs we obtained by heating mixtures of binary fluorides in a closed system 15 hitherto unknown cubic, colourless Elpasolithes. Cs₂AgAIF₆ crystallizes hexagonal in the Cs₂NaCrF₆-type of structure, but at high pressure conditions (p = 60 kbar) cubic as an Elpasolithe. The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

Über den Verteilungssatz der Auxochrome bei Azokörpern,II Dihydroxy-azobenzole

The validity of the rule of repartition of the auxochromes is examined for dihydroxy-azo and dihydroxy-4′-nitro-azo compounds with hydroxy groups in 2,4-, 3,4- and 2,5-position. In conformity with the rule the absorption maximum of the 2, 5-dihydroxy-azobenzene is situated at a considerably longer wave length than the maximum of 2,4-dihydroxy-azobenzene. The 3, 4-isomer with its absorption maximum at a relatively short wave-length seems to contradict the rule. On the other hand all alkali salts of both series conform to the rule of repartition in an impressive way.