Über die spektrale Sensibilisierung von Zinkoxid: II. Anomales Sorptionsverhalten von o,o′-Dihydroxyazofarbstoffen und Entladungskinetik des damit sensibilisierten Zinkoxids

The first acidity constants (pK₁) and the zinc complex formation constants (pK_zn) of 9 dyes of the type 1-(2-hydroxy-4′-X-5′-Y-phenylazo)-2-naphthol 1 were measured potentiometrically. The sorption behaviour of these dyes on zinc oxide in toluene demonstrates that first a Langmuir-type pseudo-equilibrium of the dye with a monomolecular edge-on adsorption ( 11 ) can be observed. The more acidic the dyes, the more is this equilibrium disguised by a faster dissolution of zinc ions from the surface to form (practically irreversibly) the polymeric 1:1 zinc-dye complex 10 . This complex is detectable in electron micrographs. The discharge kinetics of dye-sensitized zinc oxide-binder layers in the dark and under irradiation by visible light (10 interference filters) was determined. Substituents X and Y have no detectable influence on the intrinsic discharge kinetics; however, they influence the formation of the polymer complex 10 which is contrast to 11 is not a good sensitizer.     

Über die Wirkung von Auxochromen in Flavyliumsalzen,I. 7-Hydroxy-flavyliumsalze

7-Hydroxy-flavylium salts absorb at longer wave lengths than the corresponding flavylium salts, yet auxochromes in 4′-position have a less bathochromic effect in the 7-hydroxy-flavylium series than in the flavylium series. As a result the absorption maxima converge. 4′-Dimethylamino derivatives show a convergence of 22 nm.     

Einfluß von Hydrochinon auf die elektrochemische spektrale Sensibilisierung an einer CdS-Einkristallelektrode

Ohne Zusammenfassung     

Einflu? von Hydrochinon auf die elektrochemische spektrale Sensibilisierung an einer CdS-Einkristallelektrode

Ohne Zusammenfassung     

Über die Elektrokristallisation von Fulleriden

Electrocrystallization of Fullerides The fullerides P(C₆H₅)₄C₆₀ · P(C₆H₅)₄Cl, P(C₆H₅)₄C₆₀ · P(C₆H₅)₄Br und As(C₆H₅)₄C₆₀ · As(C₆H₅)₄Cl have been prepared by electrocrystallization. Single crystal structure determinations have shown them to be isostructural in space group I4/m with lattice constants a = 12.5731(9), c = 20.142(3) Å; a = 12.5378(10), c = 20.606(5) Å; a = 12.6003(11), c = 20.377(4) Å, respectively. Spectroscopic and magnetic investigations prove the existence of a C₆₀^? anion, showing orientational disorder in all three fullerides.     

Über die Oxydation von Manganoxidhydroxid

The oxidation of γ-MnOOH (manganite) in oxygen and its disproportionation in HNO₃ lead topotactically to β-MnO₂. The oxidation of synthetic α-MnOOH (groutite) in oxygen depends on its cristallite size; finely divided crystals oxidise rapidly to Mn₅O₈ which usually is stable but yields β-MnO₂ by further oxidation. Larger crystals of disperse synthetic α-MnOOH are topotactically transformed to γ-MnO₂. In HNO₃ α-MnOOH disproportionates into γ-MnO₂ and Mn²⁺. Though strictly topotactical, the reaction α-MnOOH → γ-MnO₂ is not single-phase as might be expected. The discontinuity in the function: JAHN -TELLER distortion vs. reaction rate, may simply be interpreted as the crosspoint of two different functions attributed to the crystal species α-MnOOH and γ-MnO₂, respectively. This distortion confirms the presence of Mn³⁺ in manganite and nsutite. The wide variety of possible X ray powder patterns of the phase γ-MnO₂ is explained by the superposition of, (i) cristallite size broadening, (ii) intergrowth structure effects on the profile, and (iii) BRAGG angle shifts due to substitution of part of Mn⁴⁺ by Mn³⁺.     

Über die Hydrierung von Aminalen

The catalytic hydrogenation of aminals The catalytic hydrogenation of aminals, the bis-N-analogs of acetals, was investigated. 3-(γ-Aminopropyl)-piperidines are formed by the hydrogenolytic splitting of the C–N-bond of decahydro-1, 8-naphthyridines. The reaction is stereospecifically influenced by the catalyst used. Non cyclic aminals are hydrogenated in the same manner. The mass and NMR. Spectra of 3-(γ-aminopropyl)-piperidines are discussed.     

Lanthanide induced shifts as a conformational probe for o,o,o′,o′-tetrasubstituted diphenyls

The ¹H NMR spectra of several symmetrical diphenyls, having two unlike substituents on the ortho positions of each aromatic ring, were determined in the presence of Eu(fod)₃ and of Pr(fod)₃. The lanthanide induced shifts were used to establish the more probable conformation of the molecules, as deduced from computer calculations assuming pseudocontact interactions. It was found that the two like groups are in opposite conformation and that the inter-ring angles are in the order of 15–35°.     

Über die Natur der Übergangsmetall-Kohlenstoff-σ-Bindung. VIII. Über die Reaktion von 3d-Metallhalogeniden mit Thioanisolyllithium

On the Nature of the Transition Metal Carbon-σ-Bond. VIII. Reaction of 3d-Metal Halides with Thioanisolyl Lithium Reaction of CoBr₂ · 2 THF with PhSCH₂Li/N(CH₂CH₂)₃N (TED) results in the formation of the thiophenolato complex LiCo(SPh)₃ · TED · 3.5 THF (I) with ethylene, propylene, and small amounts of cyclopropane being liberated. The constitution of I follows from the results of the elemental analysis, the effective magnetic moment (μ_eff. = 4.41 B.M.), and the reaction with acids and HgCl₂ to give PhSH and PhSHgCl, respectively. I could also be isolated by comparison synthesis from CoBr₂ · 2 THF and LiSPh/TED. Other 3d-metal halides MX_n · xTHF (M = Ti, V, Mn, Fe, Ni; X = Cl, Br) also react very easily with thioanisolyl lithium to form thiophenolato compounds.     

Über die Struktur von geschmolzenem Selendioxid

About the Structure of Molten Selenium Dioxide The Raman spectra of molten and gaseous selenium dioxide are nearly identical. The number of bands indicates the existence of a temperature depending equilibrium of monomeric and dimeric selenium dioxide in the molten and the gaseous state. A chain structure as in the crystal could not be found. An oxygen-bridged planar ring seems most likely for the structure of the dimer. Broadening of bands two intense, polarized lines at ν = 955/966 cm^?1 indicate an equilibrium of the trans-(C_2h) with the cis-structure (C_2v).     

Über die Chemisorption von Pyridinbasen an Metalldithiophosphinaten

On the Chemisorption of Pyridine Bases on Metal Dithiophosphinates The planar resp. tetrahedral metal dithiophosphinates Nil₂ ( 1 ) resp. CoL₂ ( 2 ) (L = CH₃(p-CH₃OC₆H(₄)P(S)S-) give well defined penta-or hexacoordinated adducts of the types ML₂B or ML₂B₂ with pyridine, methylpyridines or pyridine carboxylic acid esters. Enthalpies of the reaction were calorimetrically determined in some cases and the adsorption of the gaseous bases on solid 1 or 2 investigated by means of gas chromatography. The adsorption process could be satisfactorily described by LANGMUIR 's isotherme and the isosteric enthalpies of adsorption were found to 60–95 kj mol^?1. This and the observed parallelism between the “relative surface density” and the enthalpies of adduct formation as a relative measure for the bond strength M–B led to the conclusion that the bases are chemisorbed via coordinative bonds ever under the conditions of gas chromatography.     

Über die Reaktion von Alkalihexafluorosilicaten mit Aluminiumoxid

On Reactions of Alkali Hexafluorosilicates with Aluminum Oxides The reaction of Na- and K-hexafluorosilicates and α- or γ-Al₂O₃ has been investigated. Final reaction products are fluoroaluminates and alumosilicates. The reaction mechanism has been discussed. Influence of reaction parameters like time, temperature, layer thickness, and the effect of admixtures (fluorides, SiO₂) have been regarded. Tablet-reactions show the introduction of reaction by Si? F species.     

Über die thermische Trimorphie von KGaCl4

On the Thermal Trimorphism of KGaCl₄ KGaCl₄ exists in three enantiotropic forms: KGaCl₄-I is stable below ?25°C, KGaCl₄-II between ?25 and about 130°C, KGaCl₄-III above 130°C up to the melting point (259°C). KGaCl₄-III belongs to the baryte type of structure, KGaCl₄-II crystallizes with the KAlCl₄-type (distorted baryte). Thermal expansion of both forms (II, III) and the phase transition II ? III are investigated thoroughly.