Solution-shear-processed quaterrylene diimide thin-film transistors prepared by pressure-assisted thermal cleavage of swallow tails

A scalable synthesis of swallow-tailed quaterrylene diimides (STQDIs) and a method for the solution processing of sparingly soluble quaterrylene diimide (QDI) thin films are described. The pressure-assisted thermal cleavage of swallow tails yields crystalline QDI layers with electron mobility up to 0.088 cm(2) V(-1) s(-1). The developed method opens up a new route toward the solution processing of higher rylene diimides with poor solubility.     

Liquid crystalline behaviour of hydrogen-bonded complexes of alkoxycinnamic acids with octyloxystilbazole

Hydrogen-bonded liquid crystalline complexes have been obtained through 1:1 (molar ratio) complexation of 4- n -alkoxycinnamic acids ( n CNA: n = 4, 8, 10, 12, where n is the number of carbons in the alkyloxy chain) and trans -4-octyloxystilbazole (8Sz). These hydrogen-bonded complexes ( n CNA8Sz) form stable mesophases. The mesomorphic range was extended by the mixing of complexes. Hexatic modification of smectic B (SmB h ), smectic C (SmC), smectic A (SmA), and nematic mesophases of these complexes were determined by a combination of X-ray diffraction and polarizing optical microscopy. Transitions between the various smectic phases were deduced from the temperature-dependent layer spacing of n CNA8Sz. The layer spacing of these complexes in the SmB h and SmA phases gradually increased with increasing alkoxy chain length. The favouring of smectic phases in these complexes is believed to originate from the increment of polarity of the mesogen by intermolecular H-bonding.     

Modified and reverse radiometric flow injection analysis

Determination of¹³⁷Cs and⁶⁰Co by using modified and reverse radiometric flow injection analysis is described. Two component RFIA was also realized using⁶⁰Co and¹³⁷Cs radionuclides.     

Crystal structure of trans-dibromobis(triphenylphosphine)platinum(II).

Crystal structure of trans-dibromobis(triphenylphosphine)platinum(II) was determined by X-ray-crystallography. The complex crystallizes on an inversion center in distorted square planar coordination around platinum with triphenylphosphine ligands in trans positions to each other and with two molecules of dichloromethane as solvate.     

Reverse radiometric flow injection analysis (RFIA) of radioactive waste-waters with an ASIA (Ismatec) analyzer

A new application of reverse radiometric flow injection analysis is described. RFIA was used for the analysis of radioactive waste-waters. ASIA (Ismatec) analyzer with NaI(Tl) scintillation detector was used in the study of analysis of¹³¹I containing waste-water.     

Fast neutron activation analysis of Nga-Khu (Clarias Magur) fresh-water fish

14 MeV neutrons from a KAMAN A-710 neutron generator were used for the activation analysis of Nga-Khu (Clarias Magur) fresh-water fish. Na, P, K, Ca, Cl, Fe and Mg were determined in whole and in edible portions of fish.     

Aminoalkohole, 1. Mitt.: Ein Verfahren zur Synthese enantiomerenreiner 1,2-Aminoalkohole miterythro-Konfiguration

Summary The synthesis of both enantiomers of norephedrine and norisoephedrine is described to present a method for the preparation of enantiomerically pure branched 1,2-aminoalcohols. In a one pot reaction enantiomerically pure cyanohydrins bearing an acetal protective group are subjected to Grignard-reaction followed by addition of lithium aluminum hydride. After deprotection the target compounds are obtained.

Dr. Paul Löw-Beer zum 80. Geburtstag gewidmet     

Zur Herstellung von 4-Fluorenonen—eine intramolekulare Ringschlußreaktion am Indenylanion

A convenient synthesis of 4-oxofluorenes starting from 1-oxo-2-indan-butyric acid (1 a) is described. Esterification of1 a, subsequent reduction of the oxo group and elimination of the resulting hydroxy group lead to ethyl 2-inden-butyrate (3 a), which is subjected to intramolecular ring closure using NaH as condensating agent. Nitration and hydrogenation products of the resulting 1,2,3,9-tetrahydro-4-fluorenone (4 a) are described.     

Self-assembling behavior of amphiphilic dendron coils in the bulk crystalline and liquid crystalline states

We prepared a series of amphiphilic dendron coils (1-3) containing aliphatic polyether dendrons with octadecyl peripheries and a poly(ethylene oxide) (PEO) coil (DP = 44). The molecular design in this study is focused on the variation of dendron generation (from first to third) with a fixed linear coil, upon which the thermal and self-assembling behavior of the dendron coils was investigated in the bulk. All the dendron coils exhibit two crystalline phases designated as k1 (both crystalline octadecyl chains and PEO) and k2 states (crystalline octadecyl chains and molten PEO). Crystallinities for both octadecyl peripheries and the PEO decrease as generation increases. In particular, the dendron coil (3) containing third generation shows a drastic reduction of the PEO crystallinity, which is attributed to the considerable chain folding and plasticization effects by the largest hydrophilic dendritic core segment. All the crystalline phases are bilayered lamellar morphologies. On going from k1 to k2, the periodic lamellar thickness decreases in the dendron coil (1) with first generation, but interestingly increases in 3. After melting of octadecyl peripheries, 1 shows no mesophase (i.e., liquid crystalline phase). Additionally, dendron coil 2 (3) displays a network cubic mesophase with Ia3d symmetry (micellar cubic with Pm3n) which is transformed into a lamellar (hexagonal columnar) mesophase upon heating. Remarkably, the temperature-dependent mesomorphic behavior in 2 and 3 is a completely reverse pattern in comparison with conventional linear-linear block copolymers. The unusual bulk morphological phenomena in the crystalline and liquid crystalline phases can be elucidated by the dendron coil architecture and the associated coil conformational energy.