How the Magnetic Field Impacts the Chiroptical Activities of Helical Copper Enantiomers

2021 ◽  
Author(s):  
jialu wu ◽  
Bo Li ◽  
Hong Wang ◽  
Ying Zhen Lai ◽  
Yue Ye ◽  
...  

A pair of enantiomers {[Cu(L-pro)(L-tyr)]·2H2O}n (L-1) and {[Cu(D-pro)(D-tyr)]·2H2O}n (D-1) based on the chiral ligands L/D-proline and L/D-tyrosine were synthesized and investigated by single-crystal X-ray structure analysis, IR, thermogravimetric analysis, solid-state...

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 547
Author(s):  
Si Wu ◽  
Yinghao Zhu ◽  
Junchao Xia ◽  
Pengfei Zhou ◽  
Haiyong Ni ◽  
...  

We have grown La 1.37 Sr 1.63 Mn 2 O 7 single crystals with a laser-diode-heated floating-zone furnace and studied the crystallinity, structure, and magnetoresistance (MR) effect by in-house X-ray Laue diffraction, X-ray powder diffraction, and resistance measurements. The La 1.37 Sr 1.63 Mn 2 O 7 single crystal crystallizes into a tetragonal structure with space group I4/mmm at room temperature. At 0 T, the maximum resistance centers around ∼166.9 K. Below ∼35.8 K, it displays an insulating character with an increase in resistance upon cooling. An applied magnetic field of B = 7 T strongly suppresses the resistance indicative of a negative MR effect. The minimum MR value equals −91.23% at 7 T and 128.7 K. The magnetic-field-dependent resistance shows distinct features at 1.67, 140, and 322 K, from which we calculated the corresponding MR values. At 14 T and 140 K, the colossal negative MR value is down to −94.04(5)%. We schematically fit the MR values with different models for an ideal describing of the interesting features of the MR value versus B curves.


2016 ◽  
Vol 257 ◽  
pp. 107-110 ◽  
Author(s):  
Tadeusz Groń ◽  
Elzbieta Tomaszewicz ◽  
Marek Berkowski ◽  
Monika Oboz ◽  
Joachim Kusz ◽  
...  

X-ray diffraction measurement at 298 K of CdMoO4:Dy3+ showed that the molybdenum ions are tetrahedral coordinated and Cd/Dy – dodecahedral coordinated. The Dy3+ ions are randomly distributed in the unit cell, substituting the Cd2+ ones. The temperature dependence of ac and dc magnetic susceptibility showed a lack of the Curie-Weiss behaviour and a weak response to the magnetic field. The magnetization isotherms, M(H), showed a paramagnetic-diamagnetic transition at 17 K for 〈100〉 direction and at 35 K for 〈001〉 one in the magnetic field of 70 kOe. As the temperature increased this transition was moving toward smaller magnetic fields.


2015 ◽  
Vol 233-234 ◽  
pp. 137-140
Author(s):  
Dmitry A. Balaev ◽  
Oleg A. Bayukov ◽  
Evgeniy V. Eremin ◽  
M.S. Molokeev ◽  
Anatoly I. Pankrats ◽  
...  

β-Cu3Fe4(VO4)6 single crystals were synthesized. The X-ray, magnetic, Mössbauer, and EPR investigations of the crystals were fulfilled. It is established that single-crystal β-Cu3Fe4(VO4)6 is a spin glass at low temperatures. Freezing temperature varies considerably depending on the orientation of the magnetic field relative to the crystal axes. Spin-glass state is confirmed by the relaxation of the magnetization.


2014 ◽  
Vol 70 (a1) ◽  
pp. C1139-C1139
Author(s):  
Shuhei Yamane ◽  
Kenji Matsumoto ◽  
Fumiko Kimura ◽  
Tsunehisa Kimura

We have proposed magnetically oriented microcrystal array (MOMA) technique as a new technique of crystal structure analysis. With this technique, single crystal X-ray diffraction analysis is made possible from a microcrystalline powder. Biaxial crystals, having three different values of magnetic susceptibility (χ1>χ2>χ3), are aligned three dimensionally under a frequency-modulated elliptical magnetic field. Biaxial microcrystal suspended in an ultraviolet (UV) light-curable monomer matrix is aligned three dimensionally under the magnetic field, followed by consolidation of the alignment by the photopolymerization the matrix. Biaxial crystal group has three crystal systems: orthorhombic, monoclinic and triclinic systems. The analysis of crystals belonging to the triclinic system is important because ca. 23 % of organic crystals are triclinic. We have so far succeeded in determining crystal structures of orthorhombic and monoclinic systems by using the MOMA technique[1, 2, 3] but crystals of triclinic system have not been examined yet. Therefore, in this report, we attempt to determine the crystal structure of D-arabinitol, belonging to the triclinic system, by using the MOMA technique. 10 wt% D-arabinitol / XVL14 (UV light-curable monomer) suspension was subjected to 8-T magnetic field (the speed of rotation changed between 10 rpm and 40 rpm at every 900) and was consolidated by irradiation of UV light. The prepared MOMA was subjected to the X-ray diffraction measurement. The obtained diffraction spots were well resolved and the average of half widths was about 3.90. These results indicate that the D-arabinitol microcrystals were aligned three dimensionally in the MOMA and the high quality of alignment was achieved. These results indicate that the obtained diffraction patterns are equivalent to those obtained from corresponding single crystal.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Evgeny D. Filippov ◽  
Sergey S. Makarov ◽  
Konstantin F. Burdonov ◽  
Weipeng Yao ◽  
Guilhem Revet ◽  
...  

AbstractWe analyze, using experiments and 3D MHD numerical simulations, the dynamic and radiative properties of a plasma ablated by a laser (1 ns, 10$$^{12}$$ 12 –10$$^{13}$$ 13 W/cm$$^2$$ 2 ) from a solid target as it expands into a homogeneous, strong magnetic field (up to 30 T) that is transverse to its main expansion axis. We find that as early as 2 ns after the start of the expansion, the plasma becomes constrained by the magnetic field. As the magnetic field strength is increased, more plasma is confined close to the target and is heated by magnetic compression. We also observe that after $$\sim 8$$ ∼ 8  ns, the plasma is being overall shaped in a slab, with the plasma being compressed perpendicularly to the magnetic field, and being extended along the magnetic field direction. This dense slab rapidly expands into vacuum; however, it contains only $$\sim 2\%$$ ∼ 2 % of the total plasma. As a result of the higher density and increased heating of the plasma confined against the laser-irradiated solid target, there is a net enhancement of the total X-ray emissivity induced by the magnetization.


2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).


2020 ◽  
Vol 75 (4) ◽  
pp. 365-369
Author(s):  
Long Tang ◽  
Yu Pei Fu ◽  
Na Cui ◽  
Ji Jiang Wang ◽  
Xiang Yang Hou ◽  
...  

AbstractA new metal-organic framework, [Pb(hmpcaH)2]n (1), has been hydrothermally synthesized from Pb(OAc)2 · 3H2O and 2-hydroxy-6-methylpyridine-4-carboxylic acid (hmpcaH2; 2), and characterized by IR spectroscopy, elemental and thermogravimetric analysis, and single-crystal X-ray diffraction. In complex 1, each hmpcaH− ligand represents a three-connected node to combine with the hexacoordinated Pb(II) ions, generating a 3D binodal (3,6)-connected ant network. The crystal structure of 2 was determined. The solid-state fluorescence properties of 1 and 2 were investigated.


2012 ◽  
Vol 16 (01) ◽  
pp. 154-162 ◽  
Author(s):  
Edwin W.Y. Wong ◽  
Daniel B. Leznoff

The reduction of magnesium phthalocyanine (MgPc) with 2.2 equivalents of potassium graphite in 1,2-dimethoxyethane (DME) gives [K2(DME)4]PcMg(OH)(1) in 67% yield. Compound 1 was structurally characterized using single crystal X-ray crystallography and was found to be a monomeric, heterometallic complex consisting of a μ3-OH ligand that bridges a [MgIIPc3-]- anion to two potassium cations solvated by four DME molecules. An absorption spectrum of 1 confirms the Pc ligand is singly reduced and has a 3–charge. The solid-state structure of 1 does not indicate breaking of the aromaticity of the Pc ligand. Compound 1 is only the second Pc3- complex and the first reduced MgPc to be isolated and structurally characterized.


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