Nonreciprocal transport in the superconducting state of the chiral crystal NbGe_(2)

Due to the lack of inversion,mirror or other roto-inversion symmetries,chiral crystals possess a well-defined handedness which,when combined with time-reversal symmetry breaking from the application of magnetic fields,can give rise to directional dichroism of the electrical transport phenomena via the magnetochiral anisotropy.In this study,we investigate the nonreciprocal magneto-transport in microdevices of NbGe_(2),a superconductor with structural chirality.A giant nonreciprocal signal from vortex motions is observed during the superconducting transition,with the ratio of nonreciprocal resistance to the normal resistanceγreaching 6×10^(5)T^(-1)·A^(-1).Interestingly,the intensity can be adjusted and even sign-reversed by varying the current,the temperature,and the crystalline orientation.Our findings illustrate intricate vortex dynamics and offer ways of manipulation on the rectification effect in superconductors with structural chirality.

4-(7-Methoxy-2,2-dimethyl-2,3-dihydrobenzo-furan-5-yl)-N-(pyridin-2-yl)thiazol-2-amine: Chiral Crystal from Achiral Molecule

The title compound 4-（7-methoxy-2,2-dimethyl-2,3-dihydrobenzofuran-5-yl）-N- （pyridin-2-yl） thiazol-2-amine was synthesized by reacting 2-bromo-1-（7-methoxy-2,2-dime- thyl-2,3-dihydrobenzofuran-5-yl）ethanone with 1-（pyridine-2-yl）thiourea, and its crystal was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, chiral space group C2 with a = 18.1328（14）, b = 5.5969（5）, c = 19.2195（15） A, β= 115.5420（10）°, V= 1759.9（2）A3, Z = 4, F（000） = 744, C19H19N3O2S, Mr= 353.43, Dc= 1.334 g/cm3, S = 1.15, μ = 0.201 mm-1, the final R = 0.035 and wR = 0.111 for 2307 observed reflections （I 〉 2σ（I））. The Flack parameter is -0.03（10）. The preliminary bioassay result indicated that the title compound exhibits strong insecticidal activity （93.75% mortality） against Mythimna separate at the concentration of 1.000 g/L.

Dipeptide： from gel to chiral crystal

Crystallization in gel media is an important strategy for the growth of organic,inorganic and protein crystals[1].The suppression of sedimentation,convection currents and nucleation afforded by the viscous property of gel media are beneficial for obtaining crystals with improved physical properties such as fewer defects,better optical quality,and larger size[2].The gel structure has also been shown to influence the polymorphism,enantiomorphism

Synthesis and Crystal Structure of a Novel Chiral 3D Metal-organic Framework Based on an N-methyl Substituted Salan Ligand

A chiral 3D metal-organic framework [CdL].DMSO＇H20 （1） was constructed by an N-methyl substituted salan ligand （H2L）, and characterized by elemental analyses, IR, TGA, powder XRD and single-crystal X-ray crystallography. 1 crystallizes in the chiral hexagonal space group P6522 with a = b = 12.2175（3）, c = 51.450（3） A, V= 6650.9（4） A3, Z = 6, Mr = 883.45, Dc = 1.323 g.cm-3, F（000） = 2760, 2（CuKa） = 1.54178 A,β = 4.771 mm-1, GOOF = 1.041, R = 0.0313 for 3901 observed reflections with I 〉 20（/） and wR = 0.0773.1 consists of three identical sets of independent 3D frameworks interpenetrated with each other. In each set of such 3D frameworks, one half of the monomer （CdL）1/2 as the building unit forms double antiparrel helical chains which are further bridged together by other （CdL）1/2 units from adjacent helical chains. All CdL units in 1 adopt A geometry. DMSO and water guest molecules are found in the gap of the interpenetrated frameworks.

Synthesis and Crystal Structure of a Novel Chiral 1-Methylpropargyl Ester Carrying Azobenzene Moiety

A novel chiral methylpropargyl ester containing azobenzene moiety（S）-（-）-3-methyl-3-{4-[4-（n-octyloxy）phenylazophenyl]carbonyl}oxy-1-propyne 3（C25H30N2O3,Mr = 406.51） was synthesized and characterized by IR,NMR and single-crystal X-ray diffraction.The crystal is of monoclinic system,space group P21 with a=6.7610（17）,b=7.675（2）,c=22.749（7）,β=97.613（6）°,V=1170.1（6）3,Z=2,Dc=1.154,F（000）=436,μ=0.076 mm-1,R=0.0544 and wR=0.1569 for 2444 observed reflections with Ⅰ〉2σ（Ⅰ）.Structure analysis proved that the azobenzene presents a trans form, and intermolecular hydrogen bonds yield a 3D framework. The ehiral acetylene carrying azobenzene moieties can be a potential alternative nonlinear optical, helical polymer, and liquid crystalline material.

Chiral Phosphine Ligands Derived from Sugars 4.Crystal Structure of Methyl 4,6-O-Benzylidene-3-Deoxy-3-(Diphenylphosphino)-α-D-Altropyranoside (3-MBPA)

The crystal structure of the title compound 3--MBPA, C26H27O5P (Mr.= 450. 44 ). has been determined by single--crystal X-ray diffraction. The crystal ismonoclinic with space group P21, a= 9. 294(l), b= 7. 999(1), c= 15. 925(2) A,β=96. 17(5)°, V= 1176. 9 A 3, Dc=l. 271 g/cm3, F(000)=476, μ=12. 99 cm-1,Z=', Z=2, and final R = 0. 045 and Ru= 0. 057 for 1882 reflections (I≥3a(I) ). Structureanalysis revealed that the pyranose and 4, 6--O--benzylidene ring of the title compoundadopt a distorted chair conformation and the diphenylphosphino, OH and OMe groupsare in pseudo--axial position.

Molecular Chirality and Chiral Superlattice in Crystal of Tetrakis[(pyrrol-1-yl)methyl]methane

The crystal structure of tetrakis[(pyrrol-1-yl)methyl]methane was determined by X-ray diffraction measurement, and the result shows that it belongs to monoclinic crystal system, space group is P2 1/n, with a=0.9284(3) nm, b=1.0950(6) nm, c=1.8749(8) nm; α=γ= 90.00(4)°, β=103.63(3)°, V=1.8523(14) nm 3, Z=4, ρ calcd. =1.192 kg/m 3, μ=0.072 nm -1 , F(000)=712, R 1=0.0854, wR 2=0.1884. It has been found that the molecules exist in two enantiomeric states. Enantioselective self-assemblies such as one-dimensional molecular stacks in a single handedness, homochiral monolayers and a chiral superlattice are specified in this racemic crystal. In addition, a simple technique is advocated to distinguish chiral states from tetrahedral molecules in the solid state. The present R/S nomenclature of the tetracooradinated carbon centers is used solely for its convenience to distinguish the two enantiomeric states, but not used to determine the absolute configurations.

Chiral Ligands Derived from Carbohydrates.21. Crystal Structure of Methyl-4,6-O-benzylidene-3-deoxy-3-(salicylideneamino)-α-D-altropyranoside

A new chiral Schiff base derived from carbohydrate, methyl-4,6-O-benzylidene-3- deoxy-3-（salicylideneamino）-α-D-altropyranoside, has been synthesized by reacting methyl 3-amino-4,6-O-benzylidene-3-deoxy-α-D-altropyranoside with salicylaldehyde in methanol and characterized by IR, ^1H NMR, 13C NMR, MS, elemental analysis, and X-ray crystal structure analysis. The crystal belongs to orthorhombic, space group P212121 with a = 8.0856（16）, b = 10.786（2）, c = 22.690（5）A, V = 1978.8（7）A^3, Z = 4, Mr = 385.40, Dc = 1.294 g/cm^3, p = 0.095 mm^-1, F（000） = 816, the final R = 0.0379 and wR = 0.0811 for 2597 independent reflections. In the title compound, the pyrano-ring adopts a twisted ^1C4 chair conformation.

Field-induced phase transitions in chiral smectic liquid crystals studied by the constant current method

In ferroelectric liquid crystals, phase transitions can be induced by an electric field. The current constant method allows these transition to be quickly localized and thus the（E, T） phase diagram of the studied product can be obtained.In this work, we make a slight modification to the measurement principles based on this method. This modification allows the characteristic parameters of ferroelectric liquid crystal to be quantitatively measured. The use of a current square signal highlights a phenomenon of ferroelectric hysteresis with remnant polarization at null field, which points out an effect of memory in this compound.

Syntheses of Two Chiral Clusters [η~5-C_5H_4C(NR)CH_3]- RuNiM(CO)_5(μ_3-S) (R =NH-C_6H_3-2,4-(NO_2)_2,M=Mo,3;M=W,4) and the Single-crystal Structure of Cluster 3

The new chiral clusters [h5-C5H4C(NR)CH3]RuNiM(CO)5(m3-S) (R = NH-C6H3-2,4- (NO2)2, M = Mo, 3; M = W, 4) were synthesized and the structure of cluster 3 was determined by single-crystal X-ray analysis. Crystal data: C23H16O9N4MoNiRuS, Mr = 780.18, orthorhombic, space group Pbca with the following crystallographic parameters: a = 13.207(4), b = 16.036(5), c = 25.513(8) , Z = 8, V = 5403(3) 3, Dc = 1.918 g/cm3, m = 1.834 mm-1 and F(000) = 3072. The final R = 0.0512 and wR = 0.1132 for 2525 reflections with I > 2.00s(I).

STUDY ON MAGNETIC FIELD-INDUCED 0RIENTATI0N OF A CHIRAL SIDE-CHAIN LIQUID CRYSTAL POLYACRYLATE USING INFRARED DICHROISM

Magnetic field-induced orientation of a chiral side chain liquid crystalline polyacrylate(P-11) was studied by using IR dichroism. For the investigated P-11, it has been shown thatthe magnetic alignment takes place over the entire temperature range between its meltingpoint and clearing point and the orientation level is strongly temperature-dependent, thedevelopment with time of the magnetic orieatation follows an exponeotial-type relation,and the smectic phase state influences the thermal relaxation process in the absence of themagnetic field.

Synthesis and Crystal Structure of a Chiral Manganese(Ⅲ) Schiff Base Complex

A chiral salency complex,[Mn（Salency）（H2O）2]（PF6）·2H2O 1（Salency =（R,R）-N,N＇-bis（salicylidene）-1,2-cyclohexanediamine）,has been prepared by the reaction of Mn（CH3COO）3·2H2O with Salency and NH4PF6,and was established by X-ray diffraction techniques.The complex crystallizes in triclinic,space group P1 with a=9.299（8）,b=10.012（8）,c=13.461（11）,α=92.037（15）,β=92.974（12）,γ=93.530（18）°,V=1248.3（18）3,C20H28F6MnN2O6P,Mr = 592.35,Z=2,Dc=1.038 g/cm3,F（000）=608,μ=0.676 mm–1,the final R=0.0651 and wR=0.1880 for 5260 observed reflections with I 2σ（I）.

Synthesis and Phase Behavior Studies of Two New Chiral Liquid Crystals of Schiff Base——The Influence of Intramolecular Hydrogen Bond on the Phase Behavior

Two new chiral liquid crystals of schiff-base type have been synthesized.This series of compounds contain α-chloro acidic ester chain prepared from commercially available L-valine.Both of the compounds exhibit tilted smectic phases;their phase transitions were studied using DSC and polarized optical microscopy;the influence of intramolecular hydrogen bonds on the phase behavior was studied as well.

Polarization characteristics of chiral photonic crystal fibers with an elliptical hollow core

The theoretical study of dielectric-chiral photonic crystal fiber （PCF） with an elliptical hollow core is presented. The band structure of chiral photonic crystal （PhC） is calculated by using a modified plane-wave expansion （PWE） method. By examining the out-of-plane photonic bandgaps （PBGs） of chiral PhC, a kind of chiral PCF with a hollow core is designed and their eigenstates are calculated. The distributions of mode field and polarization state are demonstrated, and how the structural asymmetry of the core together with the chirality in the background affects the modal polarization is discussed. The dependences of birefringence on chirality for different ellipticities of core are investigated.

Synthesis,Characterization,X-ray Crystal Structure and Safener Activity of Chiral 2-(3-Methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-oxoethyl Acetate

The new title compound, chiral 2-（3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl）- 2-oxoethyl acetate, has been synthesized via reduction, cyclization and acylation reaction. The structure of the product has been confirmed by IR, 1H NMR, 13C NMR, LC-MS （ESI） and single-crystal X-ray diffraction. （R）-2-（3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl）-2-oxoethyl acetate crystallizes in monoclinic, space group P21/c with a = 11.867（2）, b = 8.4087（2）, c = 14.325（6） A^°, β = 117.59（2）°, Z = 4, V = 1266.9（6） A^°3, Dc = 1.307 g/cm^3, F（000） = 528, μ（MoKα） = 0.097 mm-1, R = 0.0453 and wR = 0.1237; （S）-2-（3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl）-2-oxoethyl acetate belongs to the triclinic system, space group P with a = 8.2647（17）, b = 8.7034（17）, c = 9.5479（19） A^°, α = 105.33（3）, β = 100.95（3）, γ = 105.14（3）°, Z = 2, V = 614.1（2） A^°3, Dc = 1.348 g/cm^3, F（000） = 264, μ（MoKα） = 0.10 mm-1, R = 0.0613 and wR = 0.1037. Both of the molecules prefer to form crystal packing through C–H…O hydrogen bonds.

Chiral Phosphine Ligands Derived fro m Sugars .14 . Crystal Structure of Diphenyl( m ethyl4’,6’-O-benzylidene-3’-deoxy-α- D-altropyranoside-3-)phosphine Oxide

The crystal structure of the title compound, C 26 H 27 O 6P, has been determined by single crystal X ray diffraction analysis. The crystal is orthorhombic with space group P2 12 12 1, a=6.154(4), b=17.199(8), c=22.180(3) , V=2347.6  3, D c=1.32 g/cm 3, F(000)=984, μ=1.5 cm -1 , Z =4, and final R =0.075 and R w =0.080 for 1417 reflections (I≥3σ(I)) . The X ray diffraction analysis revealed that the structure of the title compound s similar to that of its parent phosphine and the pyranose and 4, 6 O benzylidene rings remain distorted chair conformations.

Chiral Phosphine Ligands Derived from Sugars8. Crystal and Molecular Structure of Diphenyl (methyl 4', 6'-O-benzylidene-2'-deoxy-α-D-altropyranoside-2-)phosphine Oxide

The crystal structure of the title compound, C26H27O6P, has been determined by single--crystal X-ray diffraction. The crystal is monoclinic with space groupP21, a=16. 193(l), b=5. 804(1), c=12. 512(2) A, β=93. 187(5)°, V=1174. 13A3, Dc=1. 319 g/cm3, F(000) =492, μ= 13. 52 cm-1, Z= 2, and final R= 0. 042and Rw= 0. 040 for 2349 reflections (I≥3σ(I)). Structure analysis revealed that thepyranose and 4, 6-O-benzylidene ring of the title compound adopts a distorted chair conformation.

Synthesis and helical twisting property of polymerizable chiral dopant with temperature-dependent solubility in liquid crystal

In this study, right-handed dicinnamate isosorbide was synthesized via the esterification reaction betweefi optically active isosorbide and cinnamate. The chiral dopant was characterized by FT-IR, ^1H NMR, elemental analysis, SEM, UV absorption spectrum. After dissolving in a nematic liquid crystal mixture, the chiral dopant exhibited a temperature-dependent solubility in the chiral nematic liquid crystal mixture. Meanwhile, a relatively high value of helical twisting power of the polymerizable chiral dopant was determined. The results show that the chiral dopant has great potential in achieving a polymer stabilized chiral nematic liquid crystal film with a broad-band selective reflection. C 2009 Huai Yang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

SYNTHESIS AND CHARACTERIZATION OF NOVEL CHIRAL SMECTIC C(Sc~*) PHASE SHISH-KEBAB TYPE LIQUID CRYSTALLINE BLOCK COPOLYMERS

A new series of chiral shish-kebab type liquid crystal block copolymers that form the smectic C(Sc*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC, DSC, TG, POM, X-ray diffraction and polarimeter. The copolymers 7 entered into liquid crystal phase whin they were heated to their melting temperatures (T-m) and the copolymers 8 were in liquid crystal phase at room temperature with low viscosities. The smectic sanded texture or focal-conic texture were observed on POM. All the chiral block copolymers showed high optical activity. No racemization has happened. Temperature-variable X-ray diffraction study together with POM and polarimetric analysis realized that they are chiral smectic C(Sc*) phase. Thus we offer in this report the first example of shish-kebab type liquid crystal block copolymers that form a chiral smectic C(Sc*) phase. The variation of melting and isotropization temperatures with molecular structure was also discussed.