Identification and Structures of Two Main Unknown Components in the By-product from the Hydration Synthesis of Camphor

Two main unknown components in the by-product of camphor hydration synthesis were separated and identified by fine fractional distillation and spectroscopic analyses. The components with different ratios of unknown components A and B were collected by the further distillation. The combined spectral results of GC, MS,GC-MS and 13C NMR of the collected samples revealed that A is exo-2, 2, 3-trimethylbicyclo[2, 2, 1 ]heptane, and B is endo-2, 2, 3-trimethylbicyclo[2, 2, 1 ]heptane.     

Synthesis,Characterization, and Structures of α-Substituted Selenenyl-Acetophenones

Abstract

A series of α-substituted selenenyl acetophenone derivatives of the types, [PhC(OCH₂CH₂O)CH₂Se]₂, [PhC(OCH₂CH₂O)CH₂SeR], (PhCOCH₂Se)_2, and [PhCOCH₂SeR] have been prepared. These compounds have been characterized by elemental analyses, IR and NMR (¹H, ¹³C, ⁷⁷Se) spectroscopy. The compounds, [PhC(OCH₂CH₂)CH₂Se]₂ and (PhCOCH₂Se)₂ have been structurally characterized by single crystal X-ray diffraction analyses. The former shows intra-molecular Se‐?‐?‐O interaction, while the latter exhibits inter-molecular nonbonding Se‐?‐?‐O interaction.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]     

Synthesis and Crystal Structures of the α and β Forms of Bis （salicylaldoxime） copper （ Ⅱ ） Complexes

IntroductionSalicylaldoxime can be used in chemically modi-fied glassy-carbon electrodes,and applied to the deter-mination of metals in water.It shows a very high recov-ery[1,2].Direct design of solid-state structures that en-compass frameworks such as grids,ladders,helicesand channels of a desired architecture is central to crys-tal engineering science[3,4].Each of the oxidationstates of copper displays a different stereochemistry,ofwhich Cu(Ⅱ)is the most representative example foritsd9elec…     

Synthesis and Crystal Structures of the α and β Forms of Bis(salicylaldoxime)copper(Ⅱ) Complexes

Modified α and β bis(salicylaldoxime)copper(Ⅱ) have been obtained by recrystallization from ethyl acetate(CCDC Nos. 212157 & 212158). The X-ray analysis reveals that the two modificated forms have the same structure with different geometric parameters. The α form crystallizes in the P2(1)/c space group and the β form in the P1 space group. Both the crystal structures consist of centrosymmetric monomeric molecules of Cu(OC6H4CNOH)2. The IR spectra are in agreement with the structural data.     

Purification and Characterization of an Antibacterial Peptide from Rana Temporaria Chensinensis Skin

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎａｄｄｉｔｉｏｎｔｏｔｈｅｈｉｇｈｌｙｓｐｅｃｉｆｉｃｃｅｌｌ－ｍｅｄｉａｔｅｄｉｍｍｕｎｅｓｙｓｔｅｍ，ｖｅｒｔｅｂｒａｔｅｓａｎｄｏｔｈｅｒｏｒｇａｎｉｓｍｓｈａｖｅａｄｅｆｅｎｓｅｓｙｓｔｅｍｍａｄｅｕｐｏｆｄｉｓｔｉｎｃｔｇｒｏｕｐｓｏｆｂｒｏａｄ－ｓｐｅｃｔｒｕｍａｎｔｉｂａｃｔｅｒｉａｌｐｅｐｔｉｄｅｓ［１—３］．Ａｎｔｉｂａｃｔｅｒｉａｌｐｅｐｔｉｄｅｓｃａｎｂｅｃｌａｓｓｉｆｉｅｄｉｎｔｏｔｗｏｇｒｏｕｐｓｂａｓｅｄｏｎｈａｖｉｎｇｄｉｓｕｌ－ｆｉｄｅ…     

Theoretical Studies on the Structures and Reactions of Halocarbenoids(Ⅰ) Structures and Stability of

ＴｈｅｏｒｅｔｉｃａｌＳｔｕｄｉｅｓｏｎｔｈｅＳｔｒｕｃｔｕｒｅｓａｎｄＲｅａｃｔｉｏｎｓｏｆＨａｌｏｃａｒｂｅｎｏｉｄｓ（Ⅰ）ＳｔｒｕｃｔｕｒｅｓａｎｄＳｔａｂｉｌｉｔｙｏｆＣｈｌｏｒｏｃａｒｂｅｎｏｉｄＣＨＣｌ_２ＬｉＬＩＪｉ－ｈａｉ，ＦＥＮＧＳ?..     

Synthesis,Structure Characterization and Optical Properties of β Lithium Zinc Phosphate

β-LiZnPO_4 single crystal was successfully synthesized via hydrothermal method. It crystallizes in the trigonal space group R3 with a = b = 13.6490 ?, c = 9.1123 ?, γ = 120.00° and Z = 18. Structure of the crystal is constructed by LiO_4, ZnO_4 and PO_4 tetrahedral units to form a three-dimensional(3 D) framework. The crystal has a high transmission ranging from 350 to 800 nm with UV cut-off edge at 220 nm. The nonlinear optical efficiency of the as-prepared β-LiZnPO_4 is about 1.2 times as large as that of KDP(KH_2PO_4) standard. Additionally, band structure and density of states calculations for β-LiZnPO_4 were performed using the total-energy code CASTEP, based on density functional theory(DFT).     

Synthesis,Characterization and Crystal Structures of Two New Compounds of Polyoxometalates and Diaminocyclohexanetetraacetate–Copper Complexes

The two new compounds (NH₄)₂[Cu₅(H₂O)₁₀(DCTA)₂] [β-Mo₈O₂₆]·4H₂O (1) and Cu₂[Cu₃K₂(H₂O)₁₀(DCTA)₂(HBW₁₂O₄₀)]·14H₂O (2) (DCTA = 1,2-diaminocyclohexanetetraacetate anion) were synthesized in aqueous solutions and characterized by elemental analyses, TGA, IR spectroscopy and single-crystal X-ray diffraction technique. Single-crystal structure analyses indicate they are constructed by the complexes with different nuclearity and polyoxometalates. In 1 DCTA chelates Cu2 ion and bridges Cu1 and Cu3 ions, forming a tetra-nuclear-ring cation chain extending along [110] direction. In 2 DCTA chelates Cu2/Cu1 and combines Cu3 and K ions, leading to a cyclic ten-heteronuclear complex cation; the K2 ions combine the complex cations and BW₁₂O₄₀ ^5? anions, forming a complex cation-BW₁₂ layer extending on ab-plane. The variable-temperature magnetic susceptibilities of newly prepared crystalline sample of 1 were measured and 1 exhibits a weak antiferromagnetic interaction.     

Characterization of the enhanced peroxidatic activity of amyloid β peptide–hemin complexes towards neurotransmitters

Binding of heme to the amyloid peptides Aβ40/42 is thought to be an initial step in the development of symptoms in the early stages of Alzheimer’s disease by enhancing the intrinsic peroxidatic activity of heme. We found considerably higher acceleration of the reaction for the physiologically relevant neurotransmitters dopamine and serotonin than reported earlier for the artificial substrate 3,3′,5,5′-tetramethylbenzidine (TMB). Thus, the binding of hemin to Aβ peptides might play an even more crucial role in the early stages of Alzheimer’s disease than deduced from these earlier results. To mimic complex formation, a new surface architecture has been developed: The interaction between the truncated amyloid peptide Aβ1-16 and hemin immobilized on an aminohexanethiol spacer on a gold electrode has been analyzed by cyclic voltammetry. The resulting complex has a redox pair with a 25 mV more cathodic formal potential than hemin alone.     

Synthesis, Crystal Structures and Characterization of Ba5LiTiNb9O30

A new niobate compound with the chemical composition of Ba5LiTiNb9O30 was synthesized by doping Li^ into the system BaO-TiO2-Nb2O5 in conventional solid state reaction method. The crystalline structure was determined by X-ray diffraction analysis (XRD). The results showed that crystal structure of Ba5LiTiNb9O30 belongs to tetragonal tungsten bronze structure with space group P4bm and its unit cell parameters: a=b=1.2512(2) nm, c=0.4008(5)nm. The microstructure of reaction products was observed by scanning electron microscopy (SEM).     

Electronic Structures and Spectra of the Bases and Base Pairs of Nucleic Acids

The present paper covers electronic structures and spectra of the bases and the base pairs of nucleic acids calculated by using the INDO/S method. For free bases we give the energy levels of ground states and transition energies of low-lying excited states and discuss the band characters. The results indicate that the calculated spectra are in good agreement with experimental values. On the other hand, our calculations for A-T and G-C pairs are very beneficial to understanding hydrogen bond properties of these pairs.     

Synthesis, Characterization and Crystal Structures of Lanthanide Phenoxyacetate Complexes with 1,10-Phenanthroline

IntroductionTherehasbeenconsiderableinterestinthecoordinationchemistryoflanthanidecomplexeswithcarboxylateligandsduetotheirpotentialapplicationinmolecularassembliesandluminescentprobesinsystemsofbiologicalrelevance .1 4 Ofthenumerouslanthanidecomplexesthathavebeenwidelystudied,5 9mostofthemarefoundtoexhibitavarietyofdimericorinfinitechainstructure.RecentlywehavereportedpolymericLu(POA) 3(phen)compoundinwhichlutetiumionsforminfinitechainalongtheb axisdirectionthroughthecoordinationofbridgingc…     

Theoretical Studies on the Structures and Reactions of Halocarbenoids(Ⅰ)Structures and Stability of Chlorocarbenoid CHCl2

The chlorocarbenoid, CHCl₂Li, was studied by means of ab initio molecular orbital theory. Three equilibrium structures and two isomerization transition states were located. The calculations showed that the three-membered ring structure is the most stable. The "classical tetrahedral" structure is not the local minimum on the potential energy surface.     

Structural Characterization and Disulfide Assignment of Spider Peptide Phα1β by Mass Spectrometry

Native Phα1β is a peptide purified from the venom of the armed spider Phoneutria nigriventer that has been shown to have an extensive analgesic effect with fewer side effects than ω-conotoxin MVIIA. Recombinant Phα1β mimics the effects of the native Phα1β. Because of this, it has been suggested that Phα1β may have potential to be used as a therapeutic for controlling persistent pathological pain. The amino acid sequence of Phα1β is known; however, the exact structure and disulfide arrangement has yet to be determined. Determination of the disulfide linkages and exact structure could greatly assist in pharmacological analysis and determination of why this peptide is such an effective analgesic. Here, we used biochemical and mass spectrometry approaches to determine the disulfide linkages present in the recombinant Phα1β peptide. Using a combination of MALDI-MS, direct infusion ESI-MS, and nanoLC-MS/MS analysis of the undigested recombinant Phα1β peptide and digested with AspN, trypsin, or AspN/trypsin, we were able to identify and confirm all six disulfide linkages present in the peptide as Cys1-2, Cys3-4, Cys5-6, Cys7-8, Cys9-10, and Cys11-12. These results were also partially confirmed in the native Phα1β peptide. These experiments provide essential structural information about Phα1β and may assist in providing insight into the peptide’s analgesic effect with very low side effects.

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Graphical Abstract ?

     

Synthesis and Characterization of the Tetrazole Analogues of α-Amino Acids

Tetrazoles have found wide applications in coordination chemistry, medicinal chemistry and material science. Especially, when the tetrazole moiety is served as a surrogate for terminal carboxylic acid residues, the peptides have been presented some pharma…     

Syntheses, Crystal Structures and Characterization of Two New Cadmium（II） Arsonates

Two cadmium arsonate coordination polymers, Cd(HL1)2 (1, H2L1 = 4-aminophenylarsonatic acid) and Cd(H2L2)2·2H2O (2, H3L2 = 2-(4-arsonphenylamino)acetic acid), have been synthesized and characterized by IR and single-crystal X-ray diffraction. Crystal data for 1: triclinic, space group P1 with a = 5.7559(12), b = 7.0903(14), c = 8.9925(18), α = 89.04(3), β = 80.79(3), γ = 85.09(3)o, Dc = 2.496 g·cm-3, μ = 6.095 mm-1, F(000) = 260, Z = 1, the final R = 0.0574 and wR = 0.1376 for 1489 observed reflections with I > 2σ(I). And those for 2: monoclinic, space group P21/c with a = 4.7595(10), b = 9.925(2), c = 22.609(5), β = 91.81(3)°, Dc = 2.167 g·cm-3, μ = 4.168 mm-1, F(000) = 684, Z = 2, the final R = 0.0335 and wR = 0.0815 for 2340 observed reflections with I > 2σ(I). The structure of 1 shows a two-dimensional layer consisting of inorganic chains of {CdN2(AsO3)2} along the a axis linking with the phenyl groups. These layers are further linked through strong interlayer hydrogen bonding interaction to form a three-dimensional hydrogen bond supramolecular architecture. Compound 2 has inorganic chains of {CdO2(AsO3)2} similar to 1, which connect with four adjacent inorganic chains forming a three-dimensional framework.     

Syntheses,Characterization and Crystal Structures of Dithiocarbamate-based Mononuclear Palladium(Ⅱ) Complexes

By employing the dithiocarbamate salt(K(PPDC), where PPDC = 4?-pyridyl-1-piperazine-4-dithiocarbamate) as the functional ligand and di-palladium complexes [(N^N)_2Pd_2(NO_3ˉ)_2](NO3ˉ)2(N^N = 2,2?-bipyridine, bpy; 4,4?-dimethylbipyridine, dmbpy) as corner, two novel single metal complexes with Pd(II) centers have been obtained. These organic-metal complexes were characterized by NMR, ESI-MS, elemental analysis, Uv-vis spectra and single-crystal X-ray diffraction analysis. Compound 1·(PF6)2([(bpy)Pd(PPDC)]·(PF6)2) crystallizes in triclinic, space group P1, a = 8.3968(5), b = 11.5565(7), c = 18.2234(11) ?, α = 97.505(1), β = 91.424(1), γ = 106.146(1)o, C22H24N6S2P2F12 Pd, Mr = 832.93, V = 1680.58(18) ?~3, Z = 2, Dc = 1.646 Mg/m3, μ(MoK α) = 0.863 mm-1, F(000) = 828, the final R = 0.0455 and wR = 0.1390 for 6981 observed reflections with I 2σ(I). Similarly, compound 2·(PF6)2([(dmbpy)Pd(PPDC)]·(PF6)2) also crystallizes in triclinic, space group P1, a = 13.9467(3), b = 14.8390(2), c = 17.0632(3) ?, α = 81.8680(10), β = 87.051(2), γ = 83.4590(10)o, C_(22)H_(25)N_5S_2P_2F_(12)Pd, M_r = 819.93, V = 3470.81(11) ?~3, Z = 4, D_c = 1.569 Mg/m~3, μ(CuK α) = 7.115 mm~(-1), F(000) = 1632, the final R = 0.0606 and w R = 0.1637 for 12835 observed reflections with I 2σ(I). Crystallography reveals that each metal center coordinates with two N atoms from bpy and two S atoms from PPDC in the square coordination mode. In the crystal structure of complex 1, a weak Pd···Pd interaction can be observed. Interestingly, it was also found that the mononuclear moieties of complex 2 could be packed into a 3-D porous framework via multiple intermolecular C–F···H hydrogen-boding interactions which extended in the a, b, and c axes with PF_6ˉ anions frozen inside.     

Synthesis of β -chloro- and β ,β -dichlorovinylalkyldichlorosilanes

Summary A simple method of synthesis of , -dichlorovinylalkyldichlorosilanes was developed, and their alkyl and alkoxy derivatives were prepared.     

Self-Assembly of DNA–Peptide Supermolecules: Coiled-Coil Peptide Structures Templated by d-DNA and l-DNA Triplexes Exhibit Chirality-Independent but Orientation-Dependent Stabilizing Cooperativity

DNA nanostructures have been designed and used in many different applications. However, the use of nucleic acid scaffolds to promote the self-assembly of artificial protein mimics is only starting to emerge. Herein five coiled-coil peptide structures were templated by the hybridization of a d -DNA triplex or its mirror-image counterpart, an l -DNA triplex. The self-assembly of the desired trimeric structures in solution was confirmed by gel electrophoresis and small-angle X-ray scattering, and the stabilizing synergy between the two domains was found to be chirality-independent but orientation-dependent. This is the first example of using a nucleic acid scaffold of l -DNA to template the formation of artificial protein mimics. The results may advance the emerging POC-based nanotechnology field by adding two extra dimensions, that is, chirality and polarity, to provide innovative molecular tools for rational design and bottom-up construction of artificial protein mimics, programmable materials and responsive nanodevices.     

Screening and Identification of a Fungal β-Glucosidase and the Enzymatic Synthesis of Gentiooligosaccharide

After screening with 0.1% esculoside and 0.03% FeCl₃, we identified from rotten wood a fungal isolate HML0366 that produces high amount of β-glucosidase. Phenotypic and rDNA internal transcribed spacer sequence analyses indicated that the isolate belongs to Aspergillus oryzae. The β-glucosidase produced by HML0366 had an activity of 128 U/g. high performance liquid chromatography analysis also demonstrated a high transglycosylation activity of the crude enzyme. The β-glucosidase was stable between pH 4–10 at 60 °C. A gentiobiose yield of 30.86 g/L was achieved within 72 h of the enzymatic reaction at pH 5 and 55 °C using 50% glucose as the substrate. For the first time, we report here the isolation of an A. oryzae strain producing β-glucosidase with high hydrolytic activities. The crude enzyme has a high transglycosylation activity, which enables the enzymatic synthesis of gentiooligosaccharides.