Photoinduced magnetization in copper octacyanomolybdate

This article describes the studies of a photomagnetic cyanide-bridged Cu-Mo bimetallic assembly, Cu(II)(2)[Mo(IV)(CN)(8)].8H(2)O (Cu(II), S = (1)/(2); Mo(IV), S = 0) (1), which has an intervalence transfer (IT) band from Mo(IV)-CN-Cu(II) to Mo(V)-CN-Cu(I) around 480 nm. Wide-angle X-ray scattering and X-ray spectroscopic studies provide precise information about the 3D connectivity and the local environment of the transition metal ions. Irradiating with blue light causes solid 1 to exhibit a spontaneous magnetization (Curie temperature = 25 K). The thermal reversibility is carefully studied and shows the long-time stability of the photoinduced state up to 100 K. Photoreversibility is also observed; i.e., the magnetization is induced by irradiation with light below 520 nm, while the magnetization is reduced by irradiation with light above 520 nm. The UV-vis absorption spectrum after irradiation shows a decrease of the IT band and the appearance of the reverse-IT band in the region of 600-900 nm (lambda(max) = 710 nm). This UV-vis absorption spectrum is recovered to the original spectrum by irradiation with 658-, 785-, and 840-nm light. In this photomagnetic effect, the excitation of the IT band causes an electron transfer from Mo(IV) to Cu(II), producing a ferromagnetic mixed-valence isomer of Cu(I)Cu(II)[Mo(V)(CN)(8)].8H(2)O (Cu(I), S = 0; Cu(II), S = (1)/(2); Mo(V), S = (1)/(2)) (1'). 1' returns to 1 by irradiation of the reverse-IT band, which obeys the scheme for the potential energy surface in mixed-valence class II compounds.     

Sarcospan: ultrastructural localization and its relation to the sarcoglycan subcomplex

Sarcospan is a 25 kDa transmembrane component of dystrophin-associated glycoprotein. We generated a rabbit polyclonal antibody against synthetic peptide of the N-terminal domain of human sarcospan. Using this antibody we investigated the localization of sarcospan and its spacial relation to the components of sarcoglycan subcomplex in normal human skeletal myofibers by immunofluorescent microscopy and immunogold electron microscopy. In immunofluorescence the reaction was observed continuously at the myofiber surface. Ultrastructurally the gold signals of rabbit anti sarcospan antibody were present along the muscle plasma membrane, mainly at its inside surface. The triple immunogold labeled muscle samples showed that the signals of rabbit or sheep polyclonal anti alpha-, beta-, gamma- and delta-sarcoglycan antibodies and/or mouse monoclonal anti beta-, gamma- and delta-sarcoglycan antibodies were located along the muscle plasma membrane, and the cluster formation of different two or three sarcoglycan molecules was observed. The triple immunogold labeling also revealed that the signal of sarcospan molecules are present frequently in doublets and/or triplets with the components of sarcoglycan subcomplex, resulting in the cluster formation of signals of sarcoglycan and sarcospan molecules. The result of this study showed that sarcospan was expressed at the myofiber surface and that sarcospan was present in close association with alpha-, beta-, gamma- and delta-sarcoglycans and formed a functional unit with sarcoglycan subcomplex.     

Enhanced renal image contrast by ethanol fixation in phase‐contrast X‐ray computed tomography

Phase‐contrast X‐ray imaging using a crystal X‐ray interferometer can depict the fine structures of biological objects without the use of a contrast agent. To obtain higher image contrast, fixation techniques have been examined with 100% ethanol and the commonly used 10% formalin, since ethanol causes increased density differences against background due to its physical properties and greater dehydration of soft tissue. Histological comparison was also performed. A phase‐contrast X‐ray system was used, fitted with a two‐crystal X‐ray interferometer at 35 keV X‐ray energy. Fine structures, including cortex, tubules in the medulla, and the vessels of ethanol‐fixed kidney could be visualized more clearly than that of formalin‐fixed tissues. In the optical microscopic images, shrinkage of soft tissue and decreased luminal space were observed in ethanol‐fixed kidney; and this change was significantly shown in the cortex and outer stripe of the outer medulla. The ethanol fixation technique enhances image contrast by approximately 2.7–3.2 times in the cortex and the outer stripe of the outer medulla; the effect of shrinkage and the physical effect of ethanol cause an increment of approximately 78% and 22%, respectively. Thus, the ethanol‐fixation technique enables the image contrast to be enhanced in phase‐contrast X‐ray imaging.     

Multiferroics by rational design: implementing ferroelectricity in molecule-based magnets

Multiferroic materials: A novel class of multiferroics based on organic-inorganic hybrid materials is synthesized. The ferromagnetic properties originate from the coordination network, whereas the ferroelectricity results from the polar organic ions (see picture, M=magnetization and P=polarization).     

Layered hydride CaNiGeH with a ZrCuSiAs-type structure: crystal structure, chemical bonding, and magnetism induced by Mn doping

Stimulated by the discovery of the iron oxypnictide superconductor with ZrCuSiAs-type structure in 2008, extensive exploration of its isostructural and isoelectronic compounds has started. These compounds, including oxides, fluorides, and hydrides, can all be simply recognized as valence compounds for which the octet rule is valid. We report herein the first example of a ZrCuSiAs-type hydride, CaNiGeH, which violates the octet rule. This hydride was synthesized by hydrogenation of the CeFeSi-type compound CaNiGe under pressurized hydrogen. Powder diffraction and theoretical simulation confirm that H enters into the interstitial position of the Ca(4) tetrahedron, leading to notable anisotropic expansion of the unit cell along the c axis. Density functional theory calculations indicate the modification of the chemical bonding and formation of ionic Ca-H bond as a result of hydrogen insertion. Furthermore, CaNiGeH shows Pauli paramagnetism and metallic conduction similar to that of CaNiGe, but its carrier type changes to hole and the carrier density is drastically reduced as compared to CaNiGe. Mn-doping at the Ni site introduces magnetism to both the parent compound and the hydride. The measurement demonstrates that hydrogenation of CaNi(1-x)Mn(x)Ge reduces ferromagnetic ordering of Mn ions and induces huge magnetic hysteresis, whereas the spin glass state observed for the parent compound is preserved in the hydride. The hydrogenation-induced changes in the electric and magnetic properties are interpreted in terms of development of two-dimensionality in crystal structure as well as electronic state.     

Total synthesis and biological evaluation of pacidamycin D and its 3'-hydroxy analogue

Full details of the total synthesis of pacidamycin D (4) and its 3'-hydroxy analogue 32 are described. The chemically labile Z-oxyacyl enamide moiety is the most challenging chemical structure found in uridylpeptide natural products. Key elements of our approach to the synthesis of 4 include the efficient and stereocontrolled construction of the Z-oxyvinyl halides 6 and 7 and their copper-catalyzed cross-coupling with the tetrapeptide carboxamide 5, a thermally unstable compound containing a number of potentially reactive functional groups. This synthetic route also allowed us to easily prepare 3'-hydroxy analogue 32. The assemblage by cross-coupling of the Z-oxyvinyl halide 6 and the carboxamide 5 at a late stage of the synthesis provided ready access to a range of uridylpeptide antibiotics and their analogues, despite their inherent labile nature with potential epimerization, simply by altering the tetrapeptide moiety.     

Single Crystal of a Prussian Blue Analogue Based on Rubidium Manganese Hexacyanoferrate.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.     

Measurements of analyzing powers Ay, Axx, Ayy and Axz in dp elastic scattering at Ed = 56 MeV

The differential cross section and all components of the analyzing powers A_y, A_xx, A_yy and A_xz have been measured in dp elastic scattering at 56 MeV. This is the first measurement of A_xz in the cyclotron energy region. A_xz has been measured with the beam polarized in the horizontal plane using the polarization tagging method. Faddeev calculations have been performed for four cases of the NN interaction. The Coulomb correction gave smaller effects at the present energy than at lower energies. Three of them reproduce the experimental data well. The agreement between the calculations and data for A_xz was better than that reported at lower energy. The deuteron asymptotic D- to S-state ratio has been obtained and is consistent within the limits of uncertainty with previously obtained values.     

Synthesis of some antipyrinylazo and thiazolylazo compounds with pentan-2,4-dione and their reactions with metal ions

The reagents were synthesized by using pentan-2,4-dione as the coupling component with diazotized 4-aminoantipyrine or 2-aminothiazole. Two kinds of azo compounds were obtained under different conditions: 1-(4-antipyrinylazo)-1-(4-antipyrinylhydrazino)propan-2-one (Azonol A-1) and 3-(4-antipyrinylazo)pentan-2,4-dione (Azonol A-2) from 4-aminoantipyrine, and 1-(2-thiazolylazo)-1-(2-thiazolylhydrazino)propan-2-one (TAA-1) and 3-(2-thiazolylazo)pentan-2,4-dione (TAA-2) from 2-aminothiazole. The structure of Azonol A-1 was determined by single-crystal x-ray crystallography. The reactions of these reagents with various metal ions were examined. Azonol A-1 and TAA-1 form metal chelates at low pH values. Azonol A-1 is useful as a metallochromic indicator in titrations of bismuth with EDTA at pH 0.5–2, and as a spectrophotometric reagent for copper (II) (0.2–1.5 mg l^?1) at pH 0.3–1.2.