Extraction and Crystal Structure of β-Sitosterol

The title compound β-sitosterol(C29H50O), an active phytosterol in many medicinal and edible plants, was characterized by X-ray diffraction analysis and extensive nuclear magnetic resonance(NMR) data. It crystallizes in monoclinic system, space group P21 with C29H50O·1/2H2O, a = 9.4226(7), b = 7.4824(9), c = 36.889(3) , V = 2597.0(4) 3, Z = 4, Dx = 1.084 g/cm3, Mr = 423.70, F(000) = 948, and μ = 0.064 mm-1. The final R = 0.0886 and wR = 0.2234 for 10157 observed reflections(I 2σ(I)). The molecular crystal structure of β-sitosterol shows relative stereochemistry of 24R-ethylcholest-5-en-3β-ol. The molecule is composed of one steroid nucleus(3 six-membered rings and 1 five-membered ring) and one sidechain of 10 carbons. There are two C29H50O molecules and one H2O molecule in a symmetrical unit, and the title compound is stacked into a special laminated structure through hydrogen bonds and van der Waal forces. The special laminated structure was first reported.     

Synthesis, Structure and Transesterification of the Derivatives of β-Alkoxycarbonylethyltin Trichlorides with Diethyldithiocarbamate

o-Alkoxycarbonylethyltintrichlorides,RoCOCH2CH,SnCl,l,anovelmpeofmono-organotincompoundscontainingestergroup,havereceivedconsiderableattentionsinceHuttonetalreportedtheirSynthesis"'.Theirspectr8ldareshowedthatthecentCrtinatomwaspenta-coordinatedwithintramolecularestCrcarbonyloxygentotincoordinationandtheintramolecularcoordinationcanbebrokenbyextemalbidentatedonor,suchas2,2'-bipyridyI,l,1o-phenanthroline,etc.'-'.TheaddqctSoflwithneutraldonor,forexample,dimethylsulfoxide,hexamethylphosphor…     

Study on the Structure of Supramolecular Inclusion Complex of β-Cyclodextrin with Retinoic Acid

The importance of Vitamin A for human health has been stressed in resent studies1, meanwhile its derivative so-called retinoic acid (RA) has been widely used as pharmaceutical to treat several types of skin disease and cancer2,3. However the application of retinoic acid is restrained for its poor water solubility, unstability and side effect on the human body.Cyclodextrins (CDs) are macrocyclic oligosaccharides built up from 6, 7, or 8 glucopyranose units called (, (, and (-CD, respectively…     

The structural analysis of the inclusion complex of β-cyclodextrin with m-nitrophenoxyacetic acid

The inclusion complex of β-cyclodextrin with m-nitrophenoxyacetic acid was studied by single crystal X-ray diffraction,2D NMR spectroscopy and semi-empirical methods AMI.The crystallographic study shows that two β-cyclodextrins are held together by hydrogen bonds to form head-to-head dimers.The disordered guest molecule adjusts itself to attain the most stable accommodation into the cavity in which the nitro group is located at the dimer interface while the carboxyl group is buried in the primary hydroxyl groups of β-cyclodextrin.The guest inside the cavity is disordered over two sites and exhibits mobility.Moreover,2D NMR spectroscopy and theoretical study show the same inclusion behavior.In comparison to the inclusion complex of β-cyclodextrin with p-nitrophenoxyacetic acid,the host-guest stoichiometries are different,i.e.,2:1 for m-nitrophenoxyacetic acid and 1:1 for p-nitrophenoxyacetic acid,while the inclusion orientation and the packing pattern of the host are similar in both complexes.     

Structure of Potassium of Undecatungstomononickelosilicate

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Synthesis and Crystal Structure of a β-Lactam Derivative of 2,4-Diaryl-1,5-Benzothiazepine

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Large second-order optical nonlinearities of s-triazine derivatives: View from micro molecules to macro crystals

Organic nonlinear optics (NLO) is also called mo-lecular nonlinear optics. In recent years organic mate-rials have been intensively studied because of their large NLO coefficients and structural diversities[1―3]. Second harmonic generation (SHG) is a bas…     

Synthesis and Crystal Structure of β-Diketiminate Ytterbium Dichloride

1 TRODUCTIINON The monoanionic b-diketiminato ligands, [ArNC(R)CHC(R)NAr]- [1], are ideal for use with metals and have been applied for early[2] and late[3] transition metals and group 13 metal complexes[4]. These ligands have several attractive feature…     

Mechanism of simultaneously refolding and purification of proteins by hydrophobic interaction chromatographic unit and applications

The hydrophobic amino acid residues of a denatured protein molecule tend to react with the particles of the stationary phase of hydrophobic interaction chromatography (STHIC). These hydrophobic interactions prevent the denatured protein molecules from aggregating with each other. The STHIC can provide high enough energy to a denatured protein molecule to make it dehydration and to refold it into its native or various intermediate states. The outcome not only depends on the specific interactions between amino acids, the structure of STHIC, but also depends on the association between the STHIC and mobile phase. The mechanism of protein refolding and the principle of its quality control by HPHIC were also presented. By appropriate selection of the chromatographic condition, several denatured proteins can be refolded and separated simultaneously in a single chromatographic run. A specially designed unit, with diameter much larger than its length, was designed and employed for both laboratory and preparative     

Synthesis and Crystal Structure of Bis(cyclopentadienyl) Ytterbium Complex Supported by β-Diketiminate

1 INTRODUCTION Recent efforts in the design and synthesis of new ligand systems for lanthanide chemistry have been aimed at extending organolanthanide chemistry in the application of nitrogen-containing bidentate an- cillary ligands, such as β-diketiminates, guanidinates and amidinates, etc. A major impetus for such studi- es can be traced to the well known applications of lanthanide complexes in homogeneous catalysis[1, 2]. Recently, we have been interested in understanding the chemist…     

Synthesis and Structure of Dimeric β-Diketiminato Co(Ⅱ) Chloride Complex

Introduction Recently, late-transition-metal complexes have been extensively used as both inorganic and organometallic catalysts[1]. Some complexes have been developed as the novel olefin polymerization catalysts[2-4] and copolymerization catalysts for ethylene and polar comonomers[5] due to their lower oxophilicity and presumed greater functional tolerance. Moreover, compounds with imine ligands have received more attention and have been reported for the synthesis method, structure, mechanism and application[6-9]. In this contribution, we report the synthesis of the dimericβ-diketiminato Co(Ⅱ)chloride complex:     

Synthesis and Crystal Structure of （E）-Ethyl 3-Keto-18β-glycyrrhetinate 3-Oxime

A novel derivative of glycyrrhetinic acid, (E)-ethyl 3-keto-18β-glycyrrhetinate 3- oxime C32H49NO4 (Mr = 511.72), was synthesized and structurally characterized by IR, 1H NMR and single-crystal X-ray diffraction. It belongs to monoclinic, space group P21, with a = 12.4897(12), b = 7.3190(7), c = 15.9944(14) , β = 94.833(2)o, V = 1456.9(2) 3, Z = 2, Dc = 1.167 g/cm3, μ = 0.075 mm-1, F(000) = 560, the final R = 0.0449 and wR = 0.1122. A total of 7486 reflections were collected, of which 2785 were independent (Rint = 0.0199) and 2605 were observed with I > 2σ(I). There exists an intermolecular hydrogen bond which helps to stabilize the crystal structure.     

Crystal and Molecular Structure of Copper (Ⅱ) Dimeric Complex of S-Methyl-β-N-(Pyridine N-Oxide-2-ylmethylidene) Dithiocarbazate with Acetonitrile

The crystal and molecular structure of copper(Ⅱ) dimeric complex of S-methyl-B-N-(pyridine N-oxide-2-ylmethylidene) dithiocarbazate with acetonitrile, [CuL (CH3CN)]2 (ClO4)2, was determined by X-ray diffraction. The complex crystalizes in monoclinic system with space group P21/n, a= 7. 685(2), 6=20.160(6), c= 10. 847(5) A ,B = 107.89(3), Z=2,Dc=1.788 g/cm3, F(000) = 835. 8, u= 18. 17 cm-1(Moka,R= 0. 057.Each Cu(Ⅱ) ion in the complex is surrounded by a distorted square pyramidal. The basal plane is comprised of S, N and O atoms of one ligand together with a N atom of the solvent--acetonitrile, while the axial position is occupied by the S atom of the other ligand. The bond length of Cu-S(bridging) is 3. 038A . and Cu-Cu distance is 3. 700A.     

Electrochemical determination of electroinactive guests of β-cyclodextrin at a self-assembled monolayer interface

A novel determination method of electroinactive molecules by means of electrochemical technique is presented. A new self-assembled monolayer containing cyclodextrin (CD) is prepared with mono(6-o-p-tolylsulfonyl)-β-cyclodextrin. Although this derivatization process leads to a β-CD coverage of 10% of a full monolayer, this layer shows an effective host-guest response to ferrocene. The interfacial ferrocene complexation gives a response similar to that expected for a Langmuir adsorption isotherm yielding a stability constant of 4.2 ×104 mol-1· L and a maximum ferrocene coverage of 8.6×10-12 mol/cm2. The redox peak currents of the surface-confined ferrocene decrease upon addition of competing β-CD guest species to the solution, such as m-toluic acid (mTA) and sodium dodecyl sulfonate (SDS). This principle has been used for the determination of the electroinactive molecules, mTA and SDS in the concentration ranges of 0.8-2.7 μmol/L and 5-100 nmol/L, respectively.     

Synthesis and Crystal Structure of a Novel Diorganotin（Ⅳ） Complex Containing 3,4-Difluorobenzohydroxamato Ligand

In recent years, there has been considerable interest in organotin(Ⅳ) compounds. One of the important reasons is that many organotin compounds are biologically active1-3. The diorganotin(Ⅳ) complex containing carboxylate ligand have been investigated fo…     

Synthesis and Crystal Structure of α-( N-Protected a mino)β- lactam Derivative of 1 ,5-Benzothiazepine

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Synthesis and Steric Structure of β-Lactam Derivatives of 2,4-Diaryl-2,3-dihydro-1,5-benzothiazepines

2,4-Diaryl-2,3-dihydro-l,5-benicthiazepines1posscsspotentbiologicalactivities1-3.CycloadditionreactionsatC=Ndoublebondmaypeaesttheconstructionofnewcyclicsystemsthatmayhaveneweffectsonstereochemistryandbiologicalactivitiesof1,5benzothiazepines.Followingourstudyonaseriesofreactionsofcompounds1,westudiedthecycloadditionreactionof1withchloroacetylchloride.Thetitlecompoundsarepresented.Especially,theirconfiguration(therelativestericpositionoftheCIandphenylgroups)andconformationwereestablishedbyX-…     

Synthesis and Crystal Structure of Bis(cyclopentadienyl) Ytterbium Complex Supported by β-Diketiminate

Treatment of the β-diketiminate-supported ytterbium dichloride LYbCl2(THF)2 1 (L = N,N'-bis(2,6-dimethylphenyl)-2,4-pentanediiminate) with 2 equiv of C5H5Na gave rise to the title complex LYb(C5H5)2 2 (C31H35N2Yb, Mr = 608.65), and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 14.417(2), b = 10.432(2), c = 18.040(4)(A),β= 95.73(2)°, V = 2699.6(9)(A)3, Dc = 1.498 g/cm3, Z = 4,λ(MoKα) = 0.71073(A), μ = 3.485 mm(1, F(000) = 1220, the final R = 0.0304 and wR = 0.0703 for 3962 observed reflections with I > 2σ(I). In the molecular structure of the title complex, the central metal atom Yb is eight-coordinated by two cyclopentadienyl groups and two nitrogen atoms of β- diketiminate group to form a distorted tetrahedral geometry.     

Surface Modification of Polypropylene by Ethylene Plasma and Its Induced β-Form in Polypropylene

This study aims to investigate the chemical structure and morphology of plasmapolymers produced by deposition of ethylene on the surface of polypropylene. The deposition films(sediments) of ethylene plasma on the surface of polypropylene are nonuniform, and the characterization results indicate the existence of hydroxyl groups and aldehyde(or ketone) groups in the sediments. The sediment of ethylene plasma on the polypropylene surface could induce the growth of β-form crystals in the surface layer of polypropylene.     

Isolation and Crystal Structure of 3β-acetoxy-20 （29）-lupen-28-aldehyde from the Bark of Platanus Acerifolia Willd

The title compound,3β-acetoxy-20(29)-lupen-28-aldehyde,is a pentacyclic triterpene which was first isolated from the acetyl acetate fraction of Platanus acerifolia Willd bark and characterized by 1 H-NMR and 13 C-NMR.Besides,the crystal of the compound was acquired,and the relative configuration of 3β-acetoxy-20(29)-lupen-28-aldehyde was determined by single-crystal X-ray diffraction analysis for the first time.It crystallizes in the monoclinic system,space group C2 with a=14.428(3),b=6.6620(13),c=30.399(6),β=103.73(3)°,Z=4,C32 H50 O3,M r=482.72,Dc =1.130 g/cm 3,V=2838.5(10)3,μ(MoKa)=0.070 mm-1,F(000)= 1064,the final R=0.0657 and wR=0.1855 for 2839 independent reflections (R int=0.0802)and 1963 observed ones (I>2(I)).Intramolecular van der waals force contributes to the stability of the structure.