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Vol 482, No 2 (2018)
- Year: 2018
- Articles: 2
- URL: https://journals.rcsi.science/0012-5016/issue/view/9252
Physical Chemistry
Stereoisomerism of Octahedral Titanium cis-Tetrafluoro Complexes with Ph2P(O)CH2CH(OH)Me Enantiomers According to 19F NMR Data
Abstract
Effect of enantiomers of a monodentate ligand on the stereoisomerism of mixed octahedral cis-tetrafluoro complexes of d0 transition metals has been studied by 19F{1H} and 31P{1H} NMR by the example of TiF4 complexation in CH2Cl2 with Ph2P(O)CH2CH(OH)Me (L) containing asymmetric carbon atom in the aliphatic hydrocarbon group that constitutes a racemic mixture of enantiomers. Composition of complexes formed in solution has been determined, conclusion has been drawn on the relative stereochemical configuration of the chiral and meso stereoisomers of octahedral complex cis-TiF4L2 on the basis of analysis of 19F NMR spectra, using the heterotropism concept.
135-139
Phase Composition of Powder Hard Magnetic Fe–30Cr–(8–24)Co Alloys Sintered under Different Temperature Conditions
Abstract
It has been shown that for magnetic materials with a low and moderate cobalt content (8–16%), a reduced sintering temperature (up to 1150°C) can be used to produce dense compacts with practically no nonmagnetic γ-phase precipitates and good magnetic properties. To high-cobalt magnets with a cobalt content of more than 16%, this approach is not applicable. The paper presents the results of studying the dependence of the formation of the nonmagnetic γ phase on the temperature sintering conditions for a family of Fe–30%Cr alloys with a cobalt content in the range 8–24%. Sintering was carried out in a temperature range of 1150–1250°C. Magnetic hysteresis properties of materials obtained in this way are reported.
140-144