Halido-bridged Copper(II) Complexes with 1-tert-Butyl-1H-tetrazole: Crystal Structure and Magnetic Properties

Complex [Cu(tbt)Cl₂]_n (tbt = 1-tert-butyl-1H-tetrazole) was prepared by reaction of tbt with copper(II) chloride in solution. According to single-crystal X-ray analysis, this complex presents 1D coordination polymer, formed at the expense of double chlorido bridges between neighboring pentacoordinate copper(II) cations. 1-tert-Butyl-1H-tetrazole acts as monodentate ligand coordinated by Cu^II cations via the heteroring N⁴ atoms. The temperature-dependent magnetic susceptibility measurements of novel complex [Cu(tbt)Cl₂]_n as well as described previously 1D coordination polymer [Cu(tbt)₂Cl₂]_n, and linear trinuclear complex [Cu₃(tbt)₆Br₆], were carried out. Magnetic studies revealed that the copper(II) ions were weakly ferromagnetically coupled in polymeric copper(II) chloride complexes, whereas complex [Cu₃(tbt)₆Br₆] showed antiferromagnetic coupling.     

Reactivity of Bridged Pentelidene Complexes with Isonitriles: A New Way to Pentel‐Containing Heterocycles

The reaction of [Cp*E{W(CO)₅}₂] (E=P ( 1 a ), As ( 1 b ); Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl) with isonitriles RNC (R=tBu, cyclohexyl (Cy), nBu) depends on the steric demand of the substituent at the isonitrile as well as on the stoichiometry of the starting materials. With tBuNC only the Lewis acid/base adducts [Cp*E{W(CO)₅}₂(CNtBu)] (E=P ( 2 a ), As ( 2 b )) are formed. The use of Cy and n‐butylisonitrile leads first to the formation of the Lewis acid/base adduct, but only at low temperatures. At ambient temperatures, a rearrangement occurs and bicyclo[3.2.0]heptane derivatives of the type [{C(Me)C(CH₂)C(Me)C(Me)C(Me)}C(NR)‐ E{W(CO)₅}₂] (E=P, As; R=Cy, nBu) ( 3 a‐Cy , 3 b‐Cy , 3 a‐nBu and 3 b‐nBu ) are obtained. The use of a further equivalent of isonitrile results in products revealing two new structural motifs, the four‐membered ring derivatives [C(Cp*)N(R)C(NR)E{W(CO)₅}₂] ( 4 : E=P, As; R=Cy, nBu) and the bicyclic complexes [[{C(Me)C‐ (CH₂)C(Me)C(Me)C(Me)}C(NR)₂‐ E{W(CO)₅}₂] ( 5 : E=As; R=Cy). The reaction pathway depends on the substituent at the isonitrile. By treatment of 1 a with two equivalents of CyNC only a 2H‐1,3‐azaphosphet complex 4 a‐Cy (E=P; R=Cy) is formed. Treatment of 1 b with two equivalents of CyNC exclusively leads to the complex 5 b‐Cy (E=As; R=Cy). Treatment of 1 a with two equivalents of nBuNC results in a mixture of complexes, the 2H‐1,3‐azaphosphet 4 a‐nBu (E=P; R=nBu) and the bicyclic complex 5 a‐nBu (E=P; R=nBu). For the arsenidene complex 1 b a mixture of the 2H‐1,3‐azarsete complex 4 b‐nBu (E=As; R=nBu) and the bicyclic complex 5 b‐nBu (E=P, As; R=Cy, nBu) is obtained. Complex 4 b‐nBu is the first example of a 2H‐1,3‐azarsete complex. All products have been characterized by using mass spectrometry, NMR spectroscopy, and X‐ray diffraction analysis.     

Fixation of Atmospheric Nitrogen: Synthesis of Heterocycles with Atmospheric Nitrogen as the Nitrogen Source

Dry air is the source of molecular nitrogen for reactions with TiL₄, Li, and TMSCl (L = Cl, OiPr; TMS = trimethylsilyl). The nitrogen–titanium complexes thus prepared can be used to synthesize indoles, pyrroles, and lactams from carbonyl compounds. Applying this method to 1 provides access to 2 , the key compound in the synthesis of (±)-lycopodine.     

Decoration of A-Ring of a Lupane-Type Triterpenoid with Different Oxygen and Nitrogen Heterocycles

Betulinic acid (BA) was used as starting building block to create a library of novel BA-derived compounds containing O- and N-heterocycles. Firstly, BA was converted into methyl betulonate (BoOMe), which was used as intermediate in the developed methodologies. 1,2-Oxazine-fused BoOMe compounds were obtained in 12–25% global yields through a Michael addition of nitromethane to methyl (E)-2-benzylidenebetulonate derivatives, followed by nitro group reduction and intramolecular cyclization. Remarkably, the triterpene acts as a diastereoselective inducer in the conjugate addition of nitromethane, originating only one diastereomer out of four possible ones. Furthermore, other oxygen and nitrogen-containing heterocycles were installed at the A-ring of BoOMe, affording 2-amino-3-cyano-4H-pyran-fused BoOMe, diarylpyridine-fused BoOMe and 1,2,3-triazole–BoOMe compounds, using simple and straightforward synthetic methodologies. Finally, BA was revealed to be a versatile starting material, allowing the creation of a molecular diversification of compounds containing a triterpenic scaffold and O- and N-heterocycles.     

Crystal structure of lansoprazole sulfone

The structure of 2-({[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridinyl]methyl} sulfonyl)-1H-1,3-benzimidazole, C₁₆H₁₄N₃O₃F₃S, has been solved. The compound belongs to the monoclinic space group (P2₁/c) with cell parameters a = 8.8693(9) Å, b = 23.369(2) Å, c = 8.6141(8) Å, β = 104.68(1)°, V = 1727.2(3) ų, Z = 4. The final R and wR(F ²) values were 0.070 and 0.147, respectively. The title molecule has a ‘Z’ shape in the crystal structure. The fused benzimidazole moiety and the pyridine ring are nearly coplanar. The molecules are linked by N-H…N and C-H…O hydrogen bonds into chains of edge-fused R ₂ ² (14), R ₂ ² R ₂ ² (8), and R ₂ ² (18) rings along the c-axis. The crystal lattice is further strengthened by π-π stacking interactions.     

Crystal Structure of [Et_4N][Sm(S_2CNEt_2)_4]

The crystal structure of .[Et4N][Sm(S2CNEt2)4] was determined by X-ray diffraction technique. The crystal crystallizes in monoclinic system, space group P21/n with a= 1. 1695(3), b=2.0821(6), c=1.7420(7) nm, β=99. 79(3)°? Z=4, Dc= 1. 39 g/ cm3, μ(Mo/KTσ) = 18. 4 cm-1, F(000) = 1812. The structure was solved by Patterson and Fourier techniques and refined by least-squares method to a final conventional R of 0. 053 for 3116 (Ⅰ> 3σ- (Ⅰ)) reflections. Each asymmetric unit contains two ions [Sm (S2CNEt2)4]-1 and [Et4N] +1, having distance between central atoms N5 and Sm3+ to be 0. 6522 nm. The atom Sm is coordinated by eight sulphur atoms. The Sm-S distance lies in the range of 0. 285-0. 290 nm with an average of 0. 288 nm.     

Dinuclear Molybdenum(II) Complexes with Thioether Functionalized Silylamide Ligands

Treatment of molybdenum(II) acetate with thioether functionalized silylamides R₂Si(NLi-C₆H₄–2-SR')₂ leads to the formation of dinuclear Mo^II complexes [Mo₂{R₂Si(NC₆H₄-2-SR')₂}₂]. According to X-ray crystal structure analyses the complexes [Mo₂{Me₂Si(NC₆H₄-2-SMe)₂}₂] and [Mo₂{Ph₂Si(NC₆H₄-2-SPh)₂}₂] comprise a Mo₂-unit which is coordinated by two μ-κ-N,N' silylamide ligands. The coordination sphere around the molybdenum atoms consists of two amide nitrogen atoms and two thioether sulfur atoms in a distorted square-planar arrangement. The Mo-Mo distances are 211.0(1) and 211.7(1) pm, resp. In the complex [Mo₂{Ph₂Si(NC₆H₄-2-SMe)₂}₂] the silyl amide units act as tetradentate κ-N,N',S,S'chelating ligands and the Mo-Mo distance is 218.6(1) pm.     

Diastereoselective Alkylation of Activated Nitrogen Heterocycles with Alkenyl Boronate Complexes

Alkenyl boronate complexes react with acylated quinolines and isoquinolines via 1,2-metalate rearrangement to give alkylated, dearomatized heterocycles in good yields, diastereoselectivities, and regioselectivities. This multi-component coupling is highly modular and can be used to access a wide scope of heterocyclic scaffolds. Chiral boronic esters made through this methodology possess high synthetic potential and can be transformed into various functional groups in one step without racemization.     

Copper Complexes of Dicarboxy‐Functionalized Tetramethylcyclam. Crystal Structures of Complexes with the Axial Ligands Perchlorate,Chloride, and Iodide

6,13‐Dicarboxy‐1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane‐copper(II) perchlorate ( 2 a ) was synthesized via one‐step cyclocondensation from bis(N,N′‐dimethyl‐ ethylenediamine‐copper(II) perchlorate, formaldehyde and malonic acid. Anion exchange yielded the analogous copper(II) chloride ( 2 b ) and iodide ( 2 c ) complexes. Crystal structures of 2 a – 2 c show a square‐planar N₄‐co‐ordination of the copper(II) ion with RRSS configuration of the nitrogens and perchlorate, chloride or iodide ions weakly co‐ordinated axially. Relating to the macroring, the carboxy groups are in trans‐position. In 2 a , the packing is typical of parallel strands of complex subunits effected by dimerization of the carboxy groups, while in 2 b and 2 c formation of the supramolecular strands involve hydrogen bond interactions between carboxy groups and halide anions.     

L-5-羟基色氨酸粉晶晶体结构解析

以50%甲醇溶液为提取溶剂,从加纳籽中提取L-5-羟基色氨酸(HTP),采用RP-HPLC获得纯度为99.5%样品,经80%甲醇溶液重结晶获得多晶粉末.利用X射线粉末衍射技术结合计算晶体学方法解析其粉晶晶体结构,模拟图谱与实验图谱的Rwp值为5.06%.结果表明:该晶体属单斜晶系,P2_1空间群,晶胞参数为a=13.69927 ±0.01967(A),b=5.34550 ±0.00756(A),c=7.88219±0.01129(A),a=y=90.00000°,β=86.25936±0.00359°,Z=2,V=579.973(A)~3,并在此基础上对其晶体生长特性进行了分析.     

微波辐射下芳醛与活性亚甲基化合物的反应

芳醛、5，5－二甲基－1，3－环己二酮、丙二酸亚异丙酯经微波辐射发生缩合、加成、环化及消去反应，一步合成了7，7－二甲基－4－芳基－2，5－二氧代－1，2，3，4，5，6，7，8－八氢喹啉和7，7－二甲基－4－芳基－5－氧代－3，4，5，6，7，8－六氢香豆素，反应在3－5min内完成，产率优良。产物的结构经红外及核磁共振等方法确证。     

Disassembly Kinetics of Quinone‐Methide‐Based Self‐Immolative Spacers that Contain Aromatic Nitrogen Heterocycles

We prepared several pyridine‐ and pyrimidine‐based self‐immolative spacer groups to evaluate the significance of the resonance energy of the spacer aromatic ring on the kinetics of 1,4‐ and 1,6‐elimination reactions, which govern spacer disassembly. Subsequently, we relied on a photoactivation procedure to accurately analyze the disassembly kinetics. Beyond providing new results that are relevant for deriving quantitative structure–property relationships, herein, we demonstrate that pH value can be used as an efficient parameter to finely control the disassembly time of a self‐immolative spacer after an initial activation.     

氯化二氯代四苯基卟啉磷合二氯甲烷的晶体结构

氯化二氯代四苯基叶啉磷（Dichloro（5，10，15，20－tetraphenylporphinato）－phosphorus（V）chloride，［PCl2TPP］Cl）是典型的非金属卟琳配合物．据文献报导［1］该配合物能够与噻吩类化合物反应，所得单体经电解氧化，可生成具有导电性的聚合物．因此，测定［PCl2TPP］Cl的分子结构有着十分重要的意义．1标题化合物的制备及单晶生长标题化合物技文献［2］合成．用于X－射线衍射的单晶样品是将标题化合物的二氯甲烷／正庚烷混合溶液静置数周后得到的．单晶为紫色，用于X－射线衍射测定的晶粒尺寸为0．38mm×0．38mm×0．28mm．…     

Crystal structure of Ba2InTaO6 as determined by the Rietveld refinement

Rietveld profile analysis of X-ray diffraction data was carried out to determine the symmetry and crystal structures of the double perovskite Ba₂InTaO₆. Contrary to a recent study of Raman spectroscopy, we find no evidence that Ba₂InTaO₆ adopts the tetragonal space group P4/mnc of the tilt system a⁰a⁰c⁺. Instead, it has cubic symmetry with the space group Fm3¯m in the temperature range 82-723 K. In Ba₂InTaO₆ the ordering between In(III) and Ta(V) cations is a difficult process requiring prolonged heat treatment at high temperature.     

2-呋喃甲酸锶的晶体结构

在水溶液中合成并培育了2-呋喃甲酸锐Sr₆(C₅H₃O₃)₁₂单晶。经元素分析、红外光谱、差热热重分析、密度测定以及X射线衍射结构分析确定了该化合物的组成、结构和部分性质。结构分析结果表明:该晶体属单斜晶系,空间群P2₁/n,a=2.3090(7)nm,b=1.3376(4)nm,c=2.3093(6)nm,β=107.06(2)°,Z=4,R=0.0603.D_c=1.82×10³kg/m³,D_m=1.81×10³kg/m³.化合物通过羧氧桥联形成三维网状结构,其中Sr-O键的平均键长为0.2641nm,而Sr-O(羧氧)为0.2535nm,Sr-O(呋喃环氧)为0.2861nm.     

粉末衍射技术解析青蒿素晶体结构方法学比对研究

以粉末X射线衍射技术(PXRD)表征有机物晶体结构为目的,选取我国第1个全新药物青蒿素(Artemisinin)验证粉晶解析有机物晶体结构方法的合理性。粉晶解析结果为正交晶系,P212121空间群,a=23.98223±0.01624,b=9.42480±0.00645,c=6.34589±0.00439,α=β=γ=90°,Z=4,V=1434.693;单晶解析结果为正交晶系,P212121空间群,a=23.9564(9),b=9.3224(5),c=6.3205(3),α=β=γ=90°,P212121,Z=4,V=1411.55(17)3;两者所确定分子非氢结构键长、键角、二面角的相关系数分别为0.9921、0.9833和0.9997,晶胞参数基本吻合,分子构型相似。结果表明,粉晶X射线衍射技术可以求得较为准确的青蒿素晶胞参数及晶胞内分子构型。     

Statistical Inference of Distribution of Crystal Size by X-Ray Powder Diffraction

We describe a method to calculate the distribution of sizes of fine crystals from pure powder-diffraction profile using a method of maximum entropy (MAXENT). We apply a Monte-Carlo technique of simulated annealing to seek a global minimum of the error surface in fitting this diffraction profile. We consider pure diffraction profile (instrument de-convoluted) of a powder specimen without lattice imperfection to a significant extent. Under these circumstances, the distribution of the pure diffraction profile can be attributed to the distribution of crystallite size. We applied this method to three cases of crystal sizes having a highly inhomogeneous distribution with certain noise-tolerance. The results agree well with synthetic data of diffraction.