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.     

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.     

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.     

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     

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.     

Die Bestimmung von Uran(VI) neben Uran(IV), Eisen(II, III), Vanadium (III, IV, V), Molybd?n (IV, VI) und Kupfer (II)

Ohne Zusammenfassung     

Organophosphines in PtPCOX (X = N,Cl, S), PtPCNX (X = Cl,S, Br,I, As) and PtPCClX (X = S,I, As) derivatives: structural aspects

In this review are classified and analyzed structural parameters of almost 90 monomeric organoplatinum complexes with inner coordination spheres consisting of PtPCOX (X?=?N, Cl, S), PtPCNX (X?=?Cl, S, Br, I, As) and PtPCClX (X?=?S, I, As). These complexes crystallized in three crystal systems: orthorhombic (× 11), triclinic (× 32) and monoclinic (× 45). Distorted square planar arrangements about the Pt(II) atoms are provided by mono-, heterobi- and heterotridentate donor ligands. The chelating ligands create a wide variety of four-, five- and six-membered metallocyclic rings and the effects of both steric and electronic factors influence the L–Pt–L bite angles. There are wide variations in the trans-positions of the donor ligands. Two examples are classified as distortion isomers.     

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.     

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.     

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.     

M(CN)(2) Species (M = Be, Mg, Ca, Sr, Ba): Cyanides, Nitriles, or Neither?

The "cyanide" salts of the group 2 (alkaline earth) metals exhibit remarkable structural variations: CN(-) binds to the metals via the carbon, via the nitrogen, and via bridged arrangements. The most stable geometries of the beryllium and the magnesium salts are linear (CNBeNC and NCMgCN, respectively), but CaC(2)N(2), SrC(2)N(2), and BaC(2)N(2) prefer twisted, bridged structures. However, several stationary points of the bridged complexes are close in energy, and considerable fluxionality is to be expected. These theoretical predictions (MP4SDTQ/6-311+G(2d)//MP2(fu)/6-31+G, Ca, Sr, Ba: 5s5p3d1f//5s5p3d basis sets and 10 valence electron pseudopotentials) invite experimental verification.     

Crystal Structure of 3-methyl-1, 2, 3, 4, 4a, 4b, 9a, 15, 15a,15b-decahydro-(4,5);(4a,15)-dimethano-tricyclo(4, 3, 1, 0~(2,7)) deca 〔8, 9, 1, 10-a,b, c〕pyrido〔4,3-a〕-acridin-6-en-9-ol-8-one

1INTRODUCTIONIntheO-demethyIationof7a-o-amino-phenyl-6,14-endo-ethenotetrahydrothe-baine,catalyzedbyhydrobromicacid,ifinhightemperatureandprolongedtime,anewcomPoundwithyie1dof17.9%wasfound,whosestructurecannotbedeferredfromthepreviousacid-catalyzedrearrangementof6,14-endo-ethnotetrahydrothe-baines(1-33.ItwascrystallizedfromanhydrousethanolsolutionanditsstructurewasdeterminedbyX-raycrystallography.2EXPERmENTALAcrystalwithdimensionsofO.3mmXO.4mmXO.5mmwasmountedonanEnraf-NoniusCAD4d…     

Redox Routes to Substitution of Aluminum(III): Synthesis and Characterization of (IP(-))(2)AlX (IP = α-iminopyridine, X = Cl, Me, SMe, S(2)CNMe(2), C≡CPh, N(3), SPh, NHPh)

Redox active ligands are shown to facilitate a variety of group transfer reactions at redox inert aluminum(III). Disulfides can be used as a two-electron group transfer reagent, and we show that (IP(-))(2)AlSR can be formed by reaction of [(THF)(6)Na][(IP(2-))(2)Al] (1c) with disulfides RSSR (where X = C(S)NMe(2), 4; SMe, 5). In a more general redox route to substitution of aluminum bis(iminopyridine) complexes, we report zinc(II) salts as a group transfer reagent. Reaction of [((R)IP(2-))(2)Al](-) (R = H, 1c; Me, 1d) with ZnX(2) affords ((R)IP(-))(2)AlX (where IP = iminopyridine, R = H, and X = Cl, 2; CCPh, 6; N(3), 7; SPh, 8; or R = Me and X = NHPh, 9). Single crystal X-ray diffraction analysis of the complexes reveal that each of the five coordinate complexes reported here has a trigonal bipyramidal geometry with τ = 0.668 - 0.858. We observed a correlation between the greatest deviations from ideal trigonal bipyramidal symmetry (lowest τ values), the bond lengths consistent with smallest degree of ligand reduction, and the least polarizable X ligand in (IP(-))(2)AlX. Complex 4 is six-coordinate and is best described as distorted octahedral. Variable temperature magnetic susceptibility measurements indicate that each of the complexes 3-9 has a biradical electronic structure similar to previously reported 2. Magnetic exchange coupling constants in the range J = -94 to -212 cm(-1) were fit to the data for 2-9 to describe the energy of antiferromagnetic interaction between ligand radicals assuming a spin Hamiltonian of the form ? = -2J?(L(1))·?(L(2)). The strongest coupling occurs when the angle between the ligand planes is smallest, presumably to afford good overlap with the Al-X σ* orbital. Electrochemical properties of the complexes were probed using cyclic voltammetry and each of 3-9 displayed a reversible two-electron reduction and two quasi-reversible one-electron oxidation processes. The energy of the ligand based redox processes for 2-9 differ by about 150 mV over all complexes and show a correlation with the degree of IP(-) reduction observed crystallographically; more reduced IP(-) ligands require higher potentials for further reduction. Comproportionation constants that describe the equilibrium for the reaction (IP(-))(2)AlX + (IP)(2)AlX ? (IP(-))(IP)AlX fall in the range of K(c) = 10(5.7) to 10(7.9) for 3-9.     

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。     

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.     

Ca_(1-x)Zn_xTiO_3∶Pr~(3 ),R~ (R~ =Li~ ,Na~ ,K~ ,Rb~ ,Cs~ ,Ag~ )的合成和发光性质

采用X射线衍射、荧光光谱和热释发光研究了Ca1 -xZnxTiO3∶Pr3 ,R 的物相组成和发光性质。Pr3 取代Ca2 形成PrCa·正电性缺陷发光中心。激发光谱是峰值位于 3 3 0nm附近的宽带谱 ,发射光谱是峰值在 613nm半宽度为 2 0nm的带谱 ,对应Pr3 的1 D2 -3H4 跃迁发射。发光强度和余辉随基质组分Zn/Ca摩尔比和合成温度而变化。Zn2 的最佳含量在 10 %～ 2 0 %。X射线衍射研究表明掺入适量的Zn2 物相组成为CaTiO3,Ca2 Zn4 Ti1 5O36 和Zn2 TiO4 。热释发光曲线表明掺入Zn2 离子后体系中形成了新的缺陷ZnTi″ ,且ZnTi″的缺陷陷阱深度大于RCa′。     

Kristallchemische Untersuchungen in Systemen (Ti,Nb, Ta,Mo, W)−(As,Sb)

Zusammenfassung Legierungen aus den Systemen Mo–As und W–As werden röntgenographisch untersucht. Die Kristallstrukturen von MoAs und Mo₅As₄ werden bestimmt. MoAs kristallisiert im B31-Typ, Mo₅As₄ und die dazu isotypen Verbindungen (Ti_0,4W_0,6)₅As₄; Nb₅Sb₄ und Ta₅Sb₄ gehören zu einer Ti₅Te₄-artigen Struktur.