Facile Syntheses of (±)-Curcuphenol, (±)-Curcudiol, (±)-Curcuhydroquinone,and (±)-Curcuquinone

The syntheses of (±)-curcuphenol 1, (±)-curcudiol 2, (±)-curcuhydroquinone 3, and (±)-curcuquinone 4 have been achieved. The key steps involved in the syntheses were the Reformatsky reaction and hydrogenation reaction.     

Density functional study of S(N) 2 substitution reactions for CH(3) Cl + CX(1) X(2•-) (X(1) X(2) = HH, HF, HCl, HBr, HI, FF, ClCl, BrBr, and II)

A systematic investigation on the S_N2 displacement reactions of nine carbene radical anions toward the substrate CH₃Cl has been theoretically carried out using the popular density functional theory functional BHandHLYP level with different basis sets 6‐31+G (d, p)/relativistic effective core potential (RECP), 6‐311++G (d, p)/RECP, and aug‐cc‐pVTZ/RECP. The studied models are CX¹X^2?? + CH₃Cl → X²X¹CH₃C^? + Cl^?, with CX¹X^2?? = CH₂^??, CHF^??, CHCl^??, CHBr^??, CHI^??, CF₂^??, CCl₂^??, CBr₂^??, and CI₂^??. The main results are proposed as follows: (a) Based on natural bond orbital (NBO), proton affinity (PA), and ionization energy (IE) analysis, reactant CH₂^?? should be a strongest base among the anion‐containing species (CX¹X^2??) and so more favorable nucleophile. (b) Regardless of frontside attacking pathway or backside one, the S_N2 reaction starts at an identical precomplex whose formation with no barrier. (c) The back‐S_N2 pathway is much more preferred than the front‐S_N2 one in terms of the energy gaps [ΔE(front)?ΔE(back)], steric demand, NBO population analysis. Thus, the back‐S_N2 reaction was discussed in detail. On the one hand, based on the energy barriers (ΔE and ΔE) analysis, we have strongly affirmed that the stabilization of back attacking transition states (b‐TSs) presents increase in the order: b‐TS‐CI₂ < b‐TS‐CBr₂ < b‐TS‐CCl₂ < b‐TS‐CHI < b‐TS‐CHBr < b‐TS‐CHCl < b‐TS‐CF₂ < b‐TS‐CHF < b‐TS‐CH₂. On the other hand, depended on discussions of the correlations of ΔE with influence factors (PA, IE, bond order, and ΔE), we have explored how and to what extent they affect the reactions. Moreover, we have predicted that the less size of substitution (α‐atom) required for the gas‐phase reaction with α‐nucleophile is related to the α‐effect and estimated that the reaction with the stronger PA nucleophile, holding the lighter substituted atom, corresponds to the greater exothermicity given out from reactants to products. © 2012 Wiley Periodicals, Inc. J Comput Chem, 2012     

Total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine

A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo[1,2-a]azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-γ-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12.     

Ion-Exchange Processes M(II) → Fe(III) and Fe(III) → M(II) in Metal Hexacyanoferrate(II) Gelatin-Immobilized Matrices (M = Mn,Co, Ni,Cu, Zn,Cd)

Ion-exchange reactions M²⁺ Fe³⁺ and Fe³⁺ M²⁺ (M = Mn, Co, Ni, Cu, Zn, Cd) were studied in metal(II) hexacyanoferrate(II) gelatin-immobilized matrices M₂[Fe(CN)₆] in contact with aqueous FeCl₃ solutions and Fe₄[Fe(CN)₆]₃ in contact with aqueous MCl₂ solutions. It was shown that in both cases, M²⁺ was replaced by Fe³⁺ and Fe³⁺ was replaced by M²⁺ to some extent, but no complete replacement was observed in the M₂[Fe(CN)₆]–FeCl₃ or Fe₄[Fe(CN)₆]₃–MCl₂ systems under study. No electrophilic substitution Fe³⁺ Mn²⁺ was found to occur in any noticeable degree during the contact of Fe₄[Fe(CN)₆]₃ with aqueous MnCl₂ solutions even when this contact occurred for 1 h and longer.     

Sn(Ⅱ)-X和Sn(Ⅳ)-X (X=O,S,N,C,P,As,Se,Te,F,Cl,Br,I)键价参数

基于剑桥晶体数据库中同配配合物的Sn(Ⅱ)-X和Sn(Ⅳ)-X (X=O,S,N,C,P,As,Se,Te,F,Cl,Br,I)键长数据,采用键价参数B=0.037 nm拟合得到Sn(Ⅱ)-X和Sn(Ⅳ)-X的键价参数R0,这样拟合的经验参数R0中有一些是首次推出.本文所报道的Sn(Ⅱ)-O键基于B=0.037 nm的R0值(0.1956 nm)可适用于多数Sn(Ⅱ)呈各种配位数时的氧化态指定,而文献报道的B=0.055 nm和R0=0.1859 nm主要对于低配位的情况能取得Sn(Ⅱ)原子价态指定的较好结果.本研究证明,进一步研究键价参数对键价和(BVS)计算至关重要的那些可能的因素实乃当务之急.     

A位离子掺杂种类对La_(0.7)M_(0.3)Ni_(0.7)Fe_(0.3)O_3(M=Pr,Y,Sr,Zr,Ce)催化性能的影响

以聚苯乙烯胶晶(PS)为模板剂,用共沉淀法分别制备了La0. 7M0. 3Ni0. 7Fe0. 3O3(M=Pr、Y、Sr、Zr和Ce)钙钛矿复合氧化物,以乙醇水蒸气重整反应为探针,探讨了A位离子掺杂种类对La0. 7M0. 3Ni0. 7Fe0. 3O3催化活性、选择性以及积碳性能的影响。结果表明,掺杂离子均能进入了La Ni0. 7Fe0. 3O3钙钛矿晶格中,掺杂离子种类影响其晶相结构,掺杂Ce离子的样品产生较多的晶格缺陷,表面结构疏松,孔道丰富,表面吸附较多的活性氧物种,比表面积和孔径均较大。A位掺杂后钙钛矿复合氧化物还原温度有所降低,同时掺杂种类影响金属中心的形成,掺杂Ce离子的样品在还原过程中产生较多的金属中心。乙醇重整制氢反应的活性和抗积碳性能取决于样品表面活性氧物种和还原过程中产生的金属中心,表面活性氧物种协同金属中心有利于提高钙钛矿复合氧化物的活性和稳定性。     

Die Kristallstrukturen von β-TaNi3, Ta(Cu,Al)2, Nb(Cu,Al)2 und Ta6(Cu,Al)7

Zusammenfassung Neben der bekannten Phase TaNi₃ mit TiCu₃-Typ wird eine Kristallart gleicher Zusammensetzung gefunden, die mit TiAl₃ isotyp ist. Ta(Cu, Al)₂ und Nb(Cu, Al)₂ kristallisieren im MgZn₂-Typ (Laves-Phase). Ta₆(Cu, Al)₇ ist eine -Phase.     

Die Tollst?ndige Trennung von Eisen(III)-, Kobalt(II)-, Molybd?n(VI)-, Aluminium (III)- und Nickel(II)-ionen

Ohne Zusammenfassung     

Magnetic and Transport Properties of Bi_(0.5)Ca_(0.5–x)La_xFe_(0.3)Mn_(0.7)O_3(x=0, 0.05, 0.10, 0.15, 0.20, 0.25) Prepared by Molten Salt Method

Polycrystallines Bi0.5Ca0.5–xLaxFe0.3Mn0.7O3(x=0, 0.05, 0.10, 0.15, 0.20, 0.25) were prepared by molten salt method and showed perovskite orthorhombic structure with space group Pnma. The magnetic measurements indicate that the compounds exhibit antiferromagnetic behavior in a temperature range of 4―300 K. The measurements of transport properties suggest that the substitution of La for Ca enhanced the conductivity, and a kink appeared on the curve of temperature dependence of resistivity at 275 K, which is ...     

Synthesis and Crystal Structure of Bis(nitrate)- bis(N,N''''-dimethyl-N,N''''-dibenzenyl-urea)uranyl(Ⅱ)

1 INTRODUCTION Tri-butyl phosphate (TBP) has been widely used as the extraction reagent in U-Th fuel to separate uranium from thorium. But di-butyl phos- phate (DBP) and butyl phosphate (MBP), the radio- lytic products of TBP, exhibit some coordinated ability to the fission elements, such as Zr and Nb. The substitutes for TBP have being studied for several decades[1～4]. The physical and chemical properties of amides are similar to those of TBP and they selectively extract U(Ⅵ…     

(±)-Shegansu B,Gnetuhainin F, (±)-Maackin A与(±)-Cassigarol E的全合成

对四种天然二聚二苯乙烯类化合物Shegansu B (1), Gnetuhainin F (1a), Maackin A (2)以及Cassigarol E (3)的全合成进行了研究. 以3,5-二羟基苯甲酸(4)为起始原料, 经六步反应制得异丹叶大黄素(13)和白皮杉醇(14), 在HRP/H₂O₂酶催化氧化体系中, 13和14分别进行自身的氧化偶联得到各自的二聚产物. 首次完成了1a, (±)-2和(±)-3的全合成, 并以较文献报道为高的氧化偶联产率合成了(±)-1.     

STRUCTURE OF OLEAN-11, 13 ( 18 )-DIENE-3β, 16β, 23, 30-TE-TRAOL, C_(30)H_(48)O_4

<正> Clinoposide A-1, C30H48O4, Mr = 472. 71, monoclinic, P21, a = 12. 952(4), b = 6.674(5), c=15. 084(6)(?) , β= 101. 94(3)°, V= 1276(1)(?)3. Z = 2, Dc=1. 23g/cm3, μ(Mo-Ka) = 0. 74cm-1, F (000)= 520. The structure was solved by direct methods and refined to a final R = 0. 056 using 1468 observed reflections with I> 3*(I). The molecule was revealed as a compound of pentacyclic-triter-pene with tetrahydroxyl groups.     

Electrophilic Substitution Mn(II) → M(II) (M = Co,Ni, Cu,Zn, Cd) in Gelatin-Immobilized Mn2[Fe(CN)6]

Reactions of electrophilic substitution Mn(II) M(II) (M = Co, Ni, Cu, Zn, Cd) are studied in gelatin-immobilized Mn(II) hexacyanoferrate(II) systems brought in contact with aqueous solutions of metal chlorides MCl₂. As the result of this contact, Mn(II) is replaced by Co(II), Ni(II), Cu(II), Zn(II), or Cd(II) to give heteronuclear metal hexacyanoferrates(II) (MHCF) of Mn(II) and two-charged ions. Neither of the systems under study showed a complete substitution of Mn(II) or the formation of the respective mononuclear hexacyanoferrate(II) M₂[Fe(CN)₆]. When any of the above gelatin-immobilized MHCF was brought in contact with an aqueous solution of MnCl₂, no electrophilic substitution M(II) Mn(II) was observed even for a long contact time.     

Sn(II)―X和Sn(IV)―X (X=O,S, N,C, P,As, Se,Te, F,Cl, Br,I)键价参数

基于剑桥晶体数据库中同配配合物的Sn(Ⅱ)―X和Sn(Ⅳ)―X(X=O,S,N,C,P,As,Se,Te,F,Cl,Br,I)键长数据,采用键价参数B=0.037nm拟合得到Sn(Ⅱ)―X和Sn(Ⅳ)―X的键价参数R0,这样拟合的经验参数R0中有一些是首次推出.本文所报道的Sn(Ⅱ)―O键基于B=0.037nm的R0值(0.1956nm)可适用于多数Sn(Ⅱ)呈各种配位数时的氧化态指定,而文献报道的B=0.055nm和R0=0.1859nm主要对于低配位的情况能取得Sn(Ⅱ)原子价态指定的较好结果.本研究证明,进一步研究键价参数对键价和(BVS)计算至关重要的那些可能的因素实乃当务之急.     

Synthesis,characterization and magnetism of copper(Ⅱ)-lan-thanide(Ⅲ) heterobimetalic complexes with N,N'-oxamidobis-(benzoato) cuprate (Ⅱ)

Seven new μ-oxamido copper(Ⅱ)-lanthanide(Ⅲ)hetero-bitnetalic complexes described by the fonnula Cu(obbz)Ln-(Ph-phen)2NO3(Ln=La,Nd,Eu,Gd,Tb,Ho,Er),where obbz denotes the oxamidobis(benzoato)and Ph-phen represents 5-phenyl-1,10-phenanthroline,have been synthesized and characterized by the elemental analyses,spectro-scopic(IR,UV,ESR)studies,magnetic moments(at room temperature)and molar conductivity measurement.The temperature dependence of the magnetic susceptibility of Cu(obbz)Gd(Ph-phen)2NO3 complex has been measured over the range 4.2-300 K.The least-squares fit of the experimental susceptibilities based on the spin Hamiltonian operator,H=-2JS1 S2,yielded J= 1.28 cm-1,a weak ferromagnetic coupling.A plausible mechanism for a ferromagnetic coupling between Gd(Ⅲ)-Cu(Ⅱ)is discussed in terms of spin-polarization.     

Hydrothermal Synthesis,Crystal Structures,and Fluorescence Properties of Ni(II)–Ln(III) Complexes (Ln = Sm,Pr, Eu)

Three novel 3d–4f heterometal complexes [Ln(NiL)₃(Btca)(NO₃)] · xH₂O (Ln = Sm(III) (I), Pr(III) (II), Eu(III) (III) (H₂L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien, H₂Btca = benzotriazole-5-carboxylic acid) were solvothermally synthesized and characterized by singlecrystal X-ray diffraction (CIF files CCDC nos. 1555557 (I), 1555555 (II), 1555556 (III)). They crystallized in the monoclinic space group P2₁/n for I (x = 1.5) and C2/c for (II) and (III) (x = 1), respectively. In these complexes, the central Ln(III) and external nickel ions are bridged by macrocyclic oxamide groups. The metal center of Ln(III) resides in a distorted bicapped square antiprism surrounding with six oxygen atoms of three oxamide groups, two oxygen atoms of Btca^2– ion and two oxygen atoms of NO₃^-. Furthermore, there are C–H···O and/or C–H···N hydrogen bond interactions among nitrate, benzotriazole-5-carboxylate, macrocyclic oxamide and water to form three-dimensional superamolecular architecture. The fluorescence properties of the compounds I and II are also discussed.     

(S)-(-)-norlaudanosine和(S)-(-)-O,O-dimethylcoclaurine的合成

以高藜芦胺为起始原料,经N-磺酰化反应制得高藜芦磺酰胺(2);2分别与芳乙烯甲醚经对甲苯磺酸催化的Pictet-Spengler反应后用金属钠脱除Ts基团合成了(±)-norlaudanosine(5a)和(±)-O,O-dimethylcoclaurine(5b);使用半量拆分法,以N-乙酰-L-苯丙氨酸为拆分剂,制得(S)-(-)-5a和(S)-(-)-5b,其结构经1H NMR,13C NMR,IR,MS和HR-ESI-MS确证。     

A TRICHLORO-BRIDGED DIRUTHENIUM (II,III) COMPLEX: PREPARATION,PROPERTIES AND X-RAY STRUCTURE OF TRI(-μ-CHLORO) DICHLOROCARBONYLTRIS (TRIPHENYLPHOSPHINE)DIRUTHENIUM(II,III)

Abstract

The triply chloro-bridged binuclear complex [Ru₂Cl₅(CO)(PPh₃)₃]·CH₂Cl₂, (PPh₃ = triphenylphosphine), M_r = 1279.23, prepared from the precursor compound [RuCl₃(PPh₃)₂DMA]·DMA (DMA = N,N′-dimethylacetamide) and crystallizes in the monoclinic space group P2₁/c. The structure was solved from 6994 independent reflections for which I > 3σ(I) by Patterson and difference Fourier techniques and refined to a final R = 0.042. The complex is formed by two Ru atoms bridged through three chloride anions. One Ru atom is further coordinated to two non-bridging Cl atoms and a triphenylphosphine ligand, whereas the other is bonded to two PPh₃ ligands and a carbon monoxide molecule. The presence of Ru^III was confirmed by EPR data. The absence of an intervalence charge-transfer transition (IT) in the near-infrared spectrum suggests that the binuclear complex is of a localized valence type. The IR spectrum shows a ν_CO band at 1964cm^? and ν_Ru-Cl bands at 328, 280 cm^?1, corresponding to chlorides at terminal positions and 250, 225 cm^?1 for the bridged ones. Two redox processes, Ru^II/Ru^II (E_1/2 = -0.29 V) ← Ru^II/Ru^III ← (E_1/2 = 1.19 V) Ru^III/Ru^III, were observed by cyclic voltammetry.     

A helical polymeric complex,tris(benzimidazole)nickel(II) (μ-maleato)

The title polymeric complex [Ni(C₇H₆N₂)₃(C₄H₂O₄)] _n has been prepared and its crystal structure determined by single-crystal X-ray diffraction methods. The complex is orthorhombic, space group P2₁2₁2₁ with a?=?9.320(1), b?=?12.015(1), c?=?20.964(2)?Å. Three benzimidazole (bzim) and two maleate dianions coordinate to the Ni(II) atom with distorted octahedral geometry. Maleate dianions bridge neighbouring Ni(II) atoms through terminal carboxyl groups, one in monodentate and the other in chelate mode, to form polymeric molecular chains extending along the a axis. The structure is chiral, the Flack index of 0.002(10) suggesting that the helical polymeric chain is right-handed. Both intra-helical and inter-helical N–H···O hydrogen bonding occurs between bzim and carboxyl groups of maleate. The partially overlapped arrangement of nearly parallel bzim rings suggests the existence of π–π stacking in the crystal.     

Sm(Co,Cu,Fe,Zr)_(7.4)永磁合金中锆的作用

用穆斯堡尔效应等方法研究了Sm(Co,Cu,Fc,Zr)_(7.4)永磁合金中锆的作用。结果表明,锆控制合金的晶粒尺寸。锆的加入,促使铁原子由1:5相进入2:17相,同时铜和锆等非磁性原子由2:17相进入1:5相,加大了两相化学成分和磁性能的差别;促使2:17相中铁原子由Co1晶位进入Co3晶位,从而提高了合金的单轴各向异性。这两点都有利于合金矫顽力的提高。