E.s.r. spectra of mixed ligand manganese(II) dithiocarbamates

Summary E.s.r. spectra of mixed ligand manganese(II) complexes of the type Mn(dtc)₂(B), where dtc = pipyridyl dithiocarbamate (pip-dtc) or morpholyl dithiocarbamate (morph-dtc) and B = 2,2-dipyridyl (dipy) or 1,10-phenanthroline (phen), are described. The results are comparable to those calculated for D=0.19 cm^–1, =0.04, g_iso = 2.00 and for magnetic field directions parallel to principal D-tensor axes.     

Atomabsorptions-Spektrometrie zur quecksilberspezifischen Detektion in der Gas-Chromatographie

Ohne Zusammenfassung

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Atomic absorption spectrometry as a mercury specific detecting system for gas chromatography

     

Negative magnetoresistance of amorphous selenium and tellurium doped selenium

Negative magnetoresistance (MR) has been observed in bulk amorphous selenium and bulk tellurium doped selenium samples. The negative MR is found to decrease with tellurium doping. The experimental results are discussed in the light of various already existing models for negative MR.     

Effect of solid dilutin on the crystal spectra of cobalt ammonium sulphate hexahydrate

Spectra of single crystals of cobalt ammonium sulphate hexahydrate diluted with magnesium ammonium sulphate hexahydrate have been studied as a function of dilution. It has been suggested that the solid dilution lowers the vibrational perturbation and changes the crystal field parameters.     

A (1,3) Strain in cis- and trans-5, 6-dihydro-4, 6-dimethyl-4H, 8H-pyrido [3,2,1-de]phenanthridin-8-ones

The stereochemistry of trans- and cis-2, 4-dimethyl-tetrahydroquinolines, 6 and 7 were derived from ¹H-NMR. studies. These were converted respectively into trans- and cis-5, 6-dihydro-4, 6-dimethyl-4H, 8H-pyrido [3, 2, 1-de]phenanthridin-8-ones 18 and 20 by a Pschorr reaction on the anthranilamides 10 and 15 . Bromophenanthridones 19 and 21 were similarly prepared from bromoanthranilamides 12 and 17 . Detailed ¹H-NMR. studies on 18 and 20 indicated axial disposition of the methyl groups at C(2) in both compounds in contrast to the situation in 6 and 7 . This is presumably to avoid adverse CH₃CO group interaction of the A (1, 3) type. The severity of this is gauged by the preference of 20 for a normally forbidding 1, 3-diaxial orientation of two methyl groups. X-ray crystallographic studies on 19 and 20 confirm the stereochemical assignments.     

Electron and hole band structures and mobility in γ-polymorph platinum phthalocyanine

Excess electron and excess hole energy bands for γ-PtPc have been calculated using the tight-binding approximation, extended Hückel technique LCAO MO's as basis functions for constructing the Bloch functions and a modified molecular potential. The energy bands obtained are highly anisotropic. It is argued that the holes play a dominant role in the charge carrier transport in PtPc. In the absence of experimental data on PtPc, the calculated results are discussed in the light of the available results for H₂Pc and CuPc.     

Field-induced dipole reorientation and piezoelectricity in heavily plasticized nylon 11 films

Nylon 11 films with very low initial crystallinity were made by dissolving the nylon 11 in 2-ethyl-1,3-hexanediol at 150°C. Films were cast from the solution and excessive plasticizer was removed in a vacuum oven. Films were then melt pressed and quenched to yield heavily plasticized nylon 11 films containing ca. 30% by weight of the plasticizer. These films were poled under vacuum to allow the plasticizer to evaporate in the presence of an electric field. A high piezoelectric response (d₃₁ = 7.1 pC/N) was observed for the films subjected to the maximum electric field (E_p = 350 kV/cm) while the sample contained a large fraction of plasticizer. Significant development of crystallinity was observed without apparent indication of orientation of the crystallites. These studies suggest that the observed piezoelectric response originates primarily from oriented hydrogen bonds in the amorphous regions of nylon 11.