Synthesis of Analogues of (1 → 6)‐Branched (1 → 3)‐Glucohexaose

Abstract

β‐D‐Galp‐(1 → 3)‐[β‐D‐Galp‐(1 → 6)‐]α‐D‐Glcp‐(1 → 3)‐β‐D‐Glcp‐(1 → 3)‐[α‐D‐Manp‐(1 → 6)‐]D‐Glcp 16 and β‐D‐Galp‐(1 → 3)‐[β‐D‐Glcp‐(1 → 6)‐]α‐D‐Glcp‐(1 → 3)‐β‐D‐Glcp‐(1 → 3)‐[α‐D‐Manp‐(1 → 6)‐]D‐Glcp 18 were synthesized as the analogues of the immunomodulator β‐D‐Glcp‐(1 → 3)‐[β‐D‐Glcp‐(1 → 6)‐]α‐D‐Glcp‐(1 → 3)‐β‐D‐Glcp‐(1 → 3)‐[β‐D‐Glcp‐(1 → 6)‐]D‐Glcp through coupling of trisaccharide donors 8 and 13 with trisaccharide acceptor 14 followed by deprotection, respectively.     

Growth and Characterization of Crystal Nd_(0.06)Y_(0.94)Sr_6Sc(BO_3)_6

<正>The crystal of Nd0.06Y0.94Sr6Sc(BO3)6 with the dimensions up to 35 mm × 28 mm × 13 mm was grown by a top-seeded solution growth method from Li6B4O9 flux. The grown crystal was characterized by X-ray powder diffraction. The optical absorption of the crystal shows that it has a strong absorption band at 8070 A, and the absorption coefficient is 2.17cm-1 with a FWHM of 41 A, which can match with the wavelength of the diode-laser (LD) and is suitable for the LD pumping. Based on the Judd-Ofelt theory, the three parameters of line oscillator strength Ω(λ) (λ = 2, 4 and 6) of the Nd3+ion in the crystal were calculated as follows: Ω2= 1.194 × 10-20, Ω4= 4.186 × 10-20 and Ω6 = 3.351 × 10-20cm2, which are relatively larger. The results indicate that the crystal Nd0.06Y0.94Sr6Sc(BO3)6 may be a kind of high-efficient laser material for diode-pumped.     

Structure of 〔Na(DB18C6) (CH_3OH)〕_2W_6O_(19)·(DB18C6)·(CH_3OH)

1INrnODUCTIoNlnthepreviouspapers,wehavereportedthesynthesisandcrystalstructureofseveralcrownetherpolyoxometalates"-",nowwestudythestructureofthetitlecomplexandcompareitwithsomeothercrownetherpolyoxometalatecomplexes.2EXPERmENTALToal5OmLaqueoussolutioncontaining32g(1OOmol)Na,WO#.2H,Opre-justedtopH=3.5withchloricacid,14g(4Ommol)(n-Bu)'NBrwasadded,thenwhitepowderwasformed.ThewhiteprecipitateobtainedwithafiltrationwaskeptasthenewmaterialAinnextstep.AmixtureoflgAandO.3g(O.8mmol)DB18…     

Growth and Optical Properties of Sr_6YbSc(BO_3)_6 Crystal

1INTRODUCTION As is well known,the Yb3 ion has some advan-tages in comparison with Nd3 as laser active ion,for it has only two manifolds,i.e.,the ground2F7/2state and the excited2F5/2state.There is no excited state absorption reducing effective laser cross-section,no concentration quenching,no up-conversion,and three or four times longer emission lifetime than Nd3 ion.Yb3 ion exhibits a strong and broad ab-sorption band at ca.970nm and can be easily pumped with InGaAs diode lasers.The …     

Reactions of (η6-diphenylacetylene) chromiumtricarbonyl complexes with polynuclear carbonyls I. Synthesis of Cr(CO)3(η6-diphenylacetylene) complex and its reaction with Co2(CO)8. Crystal and molecular structure of Cr(CO)3(η6:η2-diphenylacetylene)Co2(CO)6

The reaction of Cr(CO)₃(NH₃)₃ with diphenylacetylene affords as a main product the complex with Cr(CO)₃ moiety bound to a phenyl ring of diphenylacetylene; Cr(CO)₃(η⁶-PhC₂Ph) (I). Complex I readily reacts with Co₂(CO)₈ yielding the mixed metal complex Cr(CO)₃(η⁶:η²-PhC₂Ph)Co₂(CO)₆ (II). The reaction proceeds with retention of the Cr(CO)₃ (η⁶-arene) structural unit, the Co₂(CO)₆ fragment being bound to the triple bond of diphenylacetylene in μ₂,η²-mode. The structure of II was determined by single crystal X-ray analysis. The complex crystallizes in space group P2₁/c with unit cell parameters a 8.666(3) Å, b 18.046(3) Å, c 15.155(6) Å. β 97.57(3)°, V 2349(2) ų, Z = 4, D_x = 1.70 g/cm³. The structure was solved by direct methods and refined by full-matrix least-squares technique to R and R_w values of 0.032 and 0.034, respectively, for 3655 observed reflections. The data obtained show that two structural units in II, Cr(CO)₃(η⁶-Ph-) and Co₂(CO)₆(μ₂,η²-CC), are distorted due to steric repulsion between these metal carbonyl moieties. The Cr(CO)₃ fragment is shifted from the centre of the phenyl ring and slightly tilted with respect to the phenyl ring plane. The Co₂C₂ tetrahedron in the Co₂(CO)₆(μ₂,η²-CC) moiety is distorted in such a way that two of the four Co_iC_j bonds are elongated.     

Probing the aromaticity of the [(H(t)Ac)3(μ2-H)6], [(H(t)Th)3(μ2-H)6],(+), and [(H(t)Pa)3(μ2-H)6] clusters

In this study we report about the aromaticity of the prototypical [(H(t)Ac)(3)(μ(2)-H)(6)], [(H(t)Th)(3)(μ(2)-H)(6)](+), and [(H(t)Pa)(3)(μ(2)-H)(6)] clusters via two magnetic criteria: nucleus-independent chemical shifts (NICS) and the magnetically induced current density. All-electron density functional theory calculations were carried out using the two-component zeroth-order regular approach and the four-component Dirac-Coulomb Hamiltonian, including scalar and spin-orbit relativistic effects. Four-component current density maps and the integration of induced ring-current susceptibilities clearly show that the clusters [(H(t)Ac)(3)(μ(2)-H)(6)] and [(H(t)Th)(3)(μ(2)-H)(6)](+) are non-aromatic whereas [(H(t)Pa)(3)(μ(2)-H)(6)] is anti-aromatic. However, for the thorium cluster we find a discrepancy between the current density plots and the classification through the NICS index. Our results also demonstrate the increasing influence of f orbitals, on bonding and magnetic properties, with increasing atomic number in these clusters. We think that the enhanced electron mobility in [(H(t)Pa)(3)(μ(2)-H)(6)] is due the significant 5f character of its valence shell. Also the participation of f orbitals in bonding is the reason why the protactinium cluster has the shortest bond lengths of the three clusters. This study provides another example showing that the magnetically induced current density approach can give more reliable results than the NICS index.     

Synthesis and crystal structure of tris(ɛ-caprolactamium) hexa(isothiocyanato)chromate(III) tricaprolactam (C6H14NO)3[Cr(NCS)6] · 3(C6H13NO)

A novel complex, tris(?-caprolactamium) hexa(isothiocyanato)chromate(III) tricaprolactam (C₆H₁₂NO)₃[Cr(NCS)₆] · 3(C₆H₁₁NO), has been synthesized and characterized by X-ray diffraction. The structure can be referred to the discrete ionic type. The coordination polyhedron of the chromium atom is a nearly regular octahedron. The crystals of the complex (C₄₂H₆₉CrN₁₂O₆S₆, FW = 1082.45) are triclinic, space group P $\overline 1 $ , Z = 1, V = 1359.3(2) ų, d _calcd = 1.322 g/cm³. Unit cell parameters: a = 11.1784(9) Å, b = 11.3196(7) Å, c = 12.580(2) Å, α = 109.347(5)°, β = 106.304(5)°, γ = 102.025(4)°. The unit cell contains three caprolactamium cations and three caprolactam molecules related by the inversion center of the space group, which leads to random occupancy of the positions of the cations and solvation molecules.     

Synthesis and Structure of a Novel Mg6 Cluster Molecule Mg6(μ3-OH)2(μ3-Br)2(μ-Br)8(THF)8

A novel Mg₆ cluster molecule with the formula of Mg₆( ₃-OH)₂( ₃-Br)₂(-Br)₈(THF)₈ (1) has been isolated in 38% yield from a reaction of the Grignard reagent, 2-naphthyl-Mg-Br with BBr₃ in THF. The structure of 1, determined by a single-crystal X-ray diffraction analysis, contains two Mg₃ triangles linked together by two bridging bromide ligands. Within each Mg₃ triangle, one hydroxide and one bromide ligand function as triply bridging ligands capping both sides of the Mg₃ triangle. The coordination geometry around each Mg(II) ion is approximately octahedral. NMR studies revealed that compound 1 is highly fluxional in solution.     

Electrochemical reductive acylation of (η6-arene)Cr(CO)3 complexes and (benzophenone)[Cr(CO)3]2

The electrochemical reductive acylation of (benzophenone)Cr(CO)₃ and (benzophenone) [Cr(CO)₃]₂ has been performed in DMF, by electrochemical reduction of complexed ketones in the presence of acetic and benzoic anhydride in excess. Three complexed benzhydryl esters ArCH(OCOR)PhCr(CO)₃, (Ar = Ph, R = Me: Ar = PhCr(CO)₃, R = Me; Ar = PhCr(CO)₃, R = Ph) were obtained in 46–57.5% yields after purification. Electrochemical reduction of (diphenylmethane)Cr(CO)₃ in the presence of acetic anhydride in excess leads to m-benzyl acetophenone.     

Synthesis and Crystal Structure of Tetraacetyldiazidoacetyl-hexaazaisowurtzitane (C_(18)H_(22)N_(12)O_6·0.5CH_3COCH_3)

1　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｃｏｎｄｅｎｓａｔｉｏｎｏｆａｌｄｅｈｙｄｅｓｗｉｔｈａｍｉｎｅｓｉｓａｖａｌｕａｂｌｅｓｙｎｔｈｅｔｉｃｍｅｔｈｏｄｌｅａｄｉｎｇｔｏｐｏｌｙａｚａｐｏｌｙｃｙｃｌｉｃｓ,ｉｎｃｌｕｄｉｎｇｃａｇｅｄｃｏｍｐｏｕｎｄｓ.Ａｎｉｍｐｏｒｔａｎｔａｐｐｌｉｃａｔｉｏｎｏｆｔｈｉｓｒｅａｃｔｉｏｎｉｓｔｈｅｓｙｎｔｈｅｓｉｓｏｆｈｅｘａｂｅｎｚｙｌｈｅｘａａｚａｉｓｏｗｕｒｔｚｉｔａｎｅ(ＨＢＩＷ)ａｎｄｉｔｓｄｅｒｉｖａｔｉｖｅｓｗｉｔｈｓｕｂｓｔｉｔｕｔｅｄｂｅｎｚ…     

Ce(NO_3)_3·C_(12)H_(24)O_6和Pr(NO_3)_3·C_(12)H_(24)O_6的晶体结构

按文献[1]合成Ce(NO_3)_3·C_(12)H_(24)O_6和Pr(NO_3)_3·C_(12)H_(24)O_6(C_(12)H_(24)O_6为18-冠-6)配合物。将配合物溶于CH_3NO_2里,室温下置于有邻苯二甲酸二辛酯干燥器内析出单晶体。在NicoletR_3M/E四园衍射仪上收集晶体X-射线衍射数据。MoK_α辐射,石墨单色器。采用θ/2θ方式扫描,于3°<2θ<45°处收集独立衍射点。对强度数据进行LP因子校正和经验吸收校正。采用Patterson函数分析得到稀土金属原子坐标,后经Fourier合成获得全部非氢原子位置,经对角块矩阵最小二乘法修正。用理论加氢得到全部氢原子坐标。最后对非氢原子进行异性修正,对氢原子进行同性修正,同时经加权修正收敛。     

Crystal structure of [Pt3S2(P(CH2OH)3)6](PF6)(OH)·H2O

[Pt₃S₂(P(CH₂OH)₃)₆](PF₆)(OH)·H₂O (1) is obtained by a reaction of [Pt₃S₂(P(CH₂OH)₃)₆]Cl₂ with NH₄PF₆. The crystal structure of 1 was determined by a single crystal X-ray diffraction analysis (space group R{ie638-1}c, a = 12.0042(2) Å, c = 52.6879(11) Å, V = 6575.2(2), Z = 6, C₁₈H₅₇F₆O₂₀P₇Pt₃S₂, d _x = 2.385 g/cm³, T = 150 K, R ₁ = 0.044 for 2123 F ₀ > 4δ(F) until 2θ_max = 63°). The cations contain a {Pt₃(μ₃-S)₂}²⁺ core with nonbonding Pt…Pt distances of 3.1536(6) Å. The Pt atoms are in a square planar environment; the Pt-S and Pt-P bond lengths are 2.3586(16) Å and 2.260(2) Å respectively.     

Crystal structure of Lebedinskii’s trisulfitotriammine Na3[Rh(SO3)3(NH3)3]·6H2O

A single crystal X-ray diffraction study of Na₃[Rh(SO₃)₃(NH₃)₃]·6H₂O was carried out (X8 APEX BRUKER automated diffractometer, MoK _α radiation, graphite monochromator); crystal data are a = 10.1844(1) Å, c = 64.0815(13) Å, V = 5756.17(14) ų, space group R $\bar 3$ c, Z = 12. The general motif of the structure was analyzed in terms of the mutual spatial arrangement of the [(NH₃)₃Rh(SO₃)₃-Na-(SO₃)₃Rh(NH₃)₃]^5? fragments, where the Na⁺ cation is surrounded by six oxygen atoms belonging to six SO₃ groups. This cation resides on the inversion center, all Na-O distances are identical, 2.347 Å. The selected fragments follow the nodes of a rhombohedral sublattice (a _c = 12.19 Å, α_c = 49.38°) formed by the intersection of three symmetry-related families of planes (1 0 2).     

Asymmetric Synthesis of (-)-(2R,3R,6S)-Irnigaine

Introduction　　Asarelativelynewmemberofnaturalalkaloidswith2 ,6 disubstituted 3 piperidinolskeleton ,irnigaine 1wasisolatedfromthetubersofArisarumVulgare (Araceae)in1995byMelhaouiandBode .1Itsstructureandrelativeconfigurationswereelucidatedby1HNMRstudiesandtheabsoluteconfigurationwasproposedonthebasisofitsopti calrotation .1Soonafterthen ,Meyerandhisco workersreportedthefirstsynthesisof (- ) (2R ,3R ,6S) irni gaineandtheconfigurationconfirmation .Althoughtheirsynthesisroutewasshortan…     

Synthesis,structural characterization and magnetic properties of a novel metallacrown [Fe6(amshz)6(C3H7NO)6]·6CH3OH

The novel 18-metallacrown-6 metallamacrocycle, with the formula of [Fe₆(amshz)₆(C₃H₇NO)₆]·6CH₃OH (1), has been synthesized by the self-assembly reaction of iron ions with N-substituted salicylhydrazide ligands. Six Fe(III) ions and six deprotonated N-acetyl-3-methylsalicylhydrazide (amshz^3?) ligands construct a planar 18-membered ring based on Fe–N–N–Fe linkage. Due to the coordination, the ligand enforces the stereochemistry of the Fe³⁺ ions as a propeller shape with alternating …ΔΛΔΛ… configurations. There exists a strong antiferromagnetic exchange interaction with μ_eff = 12.54 μ_B at 300 K between the Fe(III) spin 5/2 centers.     

Reaction of Mo(CO)6 with Alkoxide: Synthesis and Structure of the Mo(0)-OR Complex [Et4N]3[Mo2(CO)6(μ-OC6H4OCH2C6H5)3]

The reaction of molybdenum hexacarbonyl with C6H5CH2OC6H4ONa and Et4NBr in CH3CN at 60 ℃ afforded the di-nuclear Mo(0) compound [Et4N]3[Mo2(CO)6(μ-OC6H4OCH2- C6H5)3] 1. 1 crystallizes in monoclinic, space group P21/c with a=15.359(2), b=18.378(3), c=24.952(2)(A), β=102.268(4)°, V=6882.3(16) (A)3, Mr=1348.34, Z=4, Dc=1.301 g/cm3, F(000)=2832 and μ= 0.424 mm-1. The final R=0.0606 and wR=0.1552 for 9396 observed reflections (Ⅰ ＞ 2σ(Ⅰ)). 1 contains a [Mo2O3]3- core in triangular bi-pyramidal configuration and each Mo atom adopts a distorted octahedral geometry with three carbon atoms from carbonyls and three μ-O atoms from C6H5CH2OC6H4O- bridging ligands. The Mo…Mo distance is 3.30(8) (A), indicating no metalmetal bonding. A formation pathway via forming a di-molybdenum(0) di-bridging OR compound [Mo2(μ-OR)2(CO)8]2- has been figured out and the reaction of Mo(CO)6 with alkoxide has also been discussed.     

Synthesis of the first per(3-deoxy)-cyclooligosaccharide: hepta(manno-3-deoxy-6-O-t-butyldimethylsilyl)-β-cyclodextrin

Reduction of hepta(manno-2,3-anhydro-6-O-t-butyldimethylsilyl)-β-cyclodextrin with lithium triethylborohydride gives hepta(manno-3-deoxy-6-O-t-butyldimethylsilyl)-β-cyclodextrin. This compound plus the hepta(2-O-methyl)- and hepta(2-O-benzyl)-derivatives all have the ⁴C₁ conformation. Capillary GC columns manufactured with hepta(manno-2,3-anhydro-, hepta(manno-3-deoxy-2-O-methyl- and hepta(manno-2-O-benzyl-6-O-t-butyldimethylsilyl)-β-cyclodextrin stationary phases were evaluated for enantio-discrimination with 39 non-polar racemic analytes. The GC column coated with the benzyl derivative showed enantioselectivity comparable to, and in some cases superior to, a commercial per(methyl)-β-cyclodextrin column. The other columns showed little or no enantio-discrimination. A thermodynamics study established a linear enthalpy–entropy compensation effect for two series of analytes on the commercial permethyl-β-cyclodextrin column, but not for the column coated with the benzyl derivative.     

Arene complexes of zirconium containing triangular cluster cations [(η6-C6H6Me3)3Zr3(μ-Cl)6]n+,n = 2,3

Ionic -mesitylene zirconium complexes (1–4) have been obtained by a reaction between ZrCl₄ and a metal reducer (Al, Zn or Mg) in the presence of AlCl₃ in mesitylene. An X-ray study has shown that in the triangular cluster cations [(-C₆H₃Me₃Zr₃(-Cl₆)]ⁿ⁺ an increase in the charge from 2+ (1,2) to 3+ (3,4) is accompanied by shortening of the Zr-Zr distances from 3.32–3.33 A to 3.27–3.28 Å. AlCl₄ ^– (1), Al₂Cl₇ ^– (1–3), and Mg[(-Cl)₂AlCl₂]₃ ^– (4), the latter found here for the first time, are present in the complexes studied as counterions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 134–142, January, 1994.     

Pressure tuning spectroscopy of [Pt3(CO)6]2−n (n=3–5)

The pressure shifts of the first three bands appearing in the visible spectra of [Pt₃(CO)₆]²⁻_n (n = 3–5) have been measured in solution over the range 0–10 kbar. Previous electronic calculations performed on the dimer in conjunction with these results afford a possible set of assignments for the first three bands appearing in the visible spectrum for the dimer.     

Synthesis and structure of [Cr3O(CH3COO)6(H2O)3][UO2 (CH3COO)3] · 3H2O

Crystals of [Cr₃O(CH₃COO)₆(H₂O)₃][UO₂(CH₃COO)₃]·3H₂O (I) were synthesized for the first time and studied by X-ray crystallography. The crystals of I are orthorhombic: a = 8.3561(3) ?, b = 16.8421(5) ?, c = 25.7448(9) ?, V = 3623.2(2) ?³, space group P2₁2₁2₁, Z = 4, R = 0.0409. The structure is composed of trinuclear [Cr₃O(CH₃COO)₆(H₂O)₃]⁺ complexes and mononuclear [UO₂(CH₃COO)₃]^? complexes classified with crystal-chemical groups A₃M³B ₆ ² M ₃ ¹ (A = Cr³⁺, M³ = O^2?, B² = CH₃COO^?, M¹ = H₂O) and AB ₃ ⁰¹ (A = UO ₂ ²⁺ , B⁰¹ = CH₃COO^?), respectively. The complexes are bound to each other by electrostatic interactions and hydrogen bonds involving outer-sphere water molecules. The results of IR spectroscopic study of I are in good agreement with the structural data for the crystal.