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81.
The stereochemically flexible Cu(hfac)(2) metal-ligand system when combined with polyfunctional nitroxides leads to a variety of solids with varying structure and composition. While investigating the products of Cu(hfac)(2) interaction with spin-labeled pyrazole 4,4,5,5-tetramethyl-2-(1-methyl-1H-pyrazol-4-yl)-imidazoline-3-oxide-1-oxyl, we have isolated a family of (12) heterospin compounds differing in structure and composition in the solid state. In synthetic systems, these compounds often cocrystallize and must be separated mechanically. It is also shown that minor variation of the structure of the solid heterospin complex can substantially change the magnetic properties of compounds. 相似文献
82.
VI. Nevoral 《Analytical and bioanalytical chemistry》1974,268(3):189-193
In the described analysis of mineral waters, after the throughflow of the sample through a column with Dowex 50 WX 12 in H+ form, the main cations are first eluted by 1.6 N HCl and then the rare earths by 6 N HCl. The latter are separated by ion-exchange chromatography on Dowex 50WX8 in NH4 + form, the elution being performed with ammonium citrate pH 4.19. The presence of rare earths in the eluate was ascertained spectrophotometrically by means of their reaction with xylenol orange in the presence of cetylpyridinium bromide. In mineral waters from the West-Bohemian spa region it was possible to find traces of trivalent La, Ce, Pr, Nd, Sm + Gd, Y, Dy, Ho, Er, Tm, Yb and Lu. 相似文献
83.
G. V. Romanenko V. I. Ovcharenko N. V. Podberezskaya 《Journal of Structural Chemistry》1992,33(2):261-267
Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 2, pp. 118–125, March–April, 1992. 相似文献
84.
Zelenin K. N. Alekseyev V. V. Pihlaja K. Ovcharenko V. V. 《Russian Chemical Bulletin》2002,51(2):205-221
A classification and methodology of molecular design of ring—chain—ring (ring—ring) tautomeric systems by superposition of ring—chain equilibria in a structure of one molecule are considered. 相似文献
85.
86.
S. M. Aldoshin I. S. Antipin V. I. Ovcharenko S. E. Solov’eva A. S. Bogomyakov D. V. Korchagin G. V. Shilov E. A. Yur’eva F. B. Mushenok K. V. Bozhenko A. N. Utenyshev 《Russian Chemical Bulletin》2013,62(2):536-542
A new representative of calix[4]arene-containing tetranuclear manganese complexes of the [MnII 2MnIII 2] type was obtained. According to the data of magnetoochemical studies, the complex exhibits properties of molecular magnet at the temperature below 5 K. Parameters of the exchange interaction and the activation energy were determined. The influence of the peripheral environment on the magnetic properties of the tetranuclear manganese framework in the structure of the complex was revealed. 相似文献
87.
Results of laboratory measurements of the weak-localization effect for light scattered by surfaces with different characteristics are presented. The measurements were made in a range of phase angles of 0.2°–3.5°. The aim of the measurements was to study the influence of the choice of surface material (metal, dielectric), the size of particles of the scattering surface, their packing density, the reflectivity of a sample, and the wavelength of incident radiation on the effect. For the measurements, both nonpolarized and linearly polarized light was used. Powders of dielectric materials were found to enhance the weak-localization effect with increasing particle size, but the effect weakened starting with a certain size of the order of wavelength. The pressing of powders of dielectric transparent materials enhanced the opposition effect. This was most pronounced for samples with small-sized particles. The phase dependence of brightness became wider and more linear with decreasing reflectivity of the surface. A qualitative difference in the behavior of the phase dependence for the ratio of cross-and copolarized components was observed. For metals and metal-like materials, the ratio increased with decreasing phase angle. Dielectrics were found to have an opposite dependence. 相似文献
88.
89.
E. V. Tretyakov S. V. Fokin E. Yu. Fursova O. V. Kuznetsova G. V. Romanenko R. Z. Sagdeev V. I. Ovcharenko 《Russian Chemical Bulletin》2013,62(8):1803-1808
As part of continuing studies of multispin compounds capable of exhibiting chemomechanical activity, a series of heterospin solids of the composition [Cu(hfac)2L x L′2?x ], [Cu(hfac)2L′], [Cu2(Piv)4L′2]·0.5C6H14, and [Cu2(hfac)2(Piv)2L′2], where hfac is the hexafluoroacetylacetonate anion, L is 4,4,5,5-tetramethyl-2-(1-methyl-1H-imidazol-5-yl)-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl, L′ is the imino nitroxide analog of L, viz., 4,4,5,5-tetramethyl-2-(1-methyl-1H-imidazol-5-yl)-4,5-dihydro-1H-imidazole-1-oxyl, and Piv is the 2,2-dimethylpropionate anion, were synthesized and characterized. The packing of the synthesized crystals of the solid solutions [Cu(hfac)2L x L′2-x ], where L predominates, is similar to that for [Cu(hfac)2L2], and these crystals are able to undergo chemomechanical motion. On the contrary, the crystals of [Cu(hfac)2L x L′2?x ], where L′ predominates, have structural parameters similar to those of [Cu(hfac)2L′2] and do not exhibit thermally activated or photoactivated chemomechanical activity. 相似文献
90.
The Ce,Mn mixed-metal polynuclear compounds [Ce 3Mn6(O)5(OH)3Piv12Cl2(THF)3]·2THF, [Ce3Mn8(O)8Piv16Cl2(HPiv)2]·C7H16, [Ce10Mn4(O)6(OH)12Piv16Cl2(THF)2]·2THF·2H2O, [CeMn11Cl3(O)8Piv15(H2O)]·CH2Cl2, and [CeMn8(O)8Piv12(HPiv)2(THF)2] were prepared and structurally characterized. The possibility of synthesizing p,d,f-heterospin complexes by replacing coordinated
THF molecules by nitroxide molecules was exemplified by the reaction of [Ce3Mn6(O)5(OH)3Piv12Cl2(THF)3]·2THF with nitronyl nitroxides (NIT-R is 2-R-4,4,5,5-tetramethyl-24midazoline-l-oxyl 3-oxide; R is Me or 4-Py). The X-ray
diffraction study of these complexes showed that [Ce3Mn6(O)5(OH)3Piv12Cl2(HPiv)(NIT-Me)2] and [CeMn8(O)8Piv12(NIT4-Py) 4] · 2C6H14 have a molecular structure and [Ce3Mn6(O)5(OH)3-Piv12Cl2(NIT-Me)(H2O)] is an infinite chain. 相似文献