bluuebunny/crossref_metadata_2025 huggingface dataset:
A New One-Dimensional Coordination Polymer of Silver(I) with Bridging 2-(2-Aminoethyl)pyridine and Nitrato Ligands: [Ag2(μ–NO3)2(μ–aepy)2]n
Authors: Senelaa Evrim , Yilmaz Veysel T. , Harrison William T. A.
Published: August 2018

A new silver(I) nitrate complex of 2-(2-aminoethyl)pyridine (aepy), [Ag2(μ-NO3)2(μ-aepy)2]n, has been synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffractometry. Two silver(I) ions are doubly bridged by two bidentate aepy ligands forming dimeric building block [Ag2(μ-aepy)2] units with a Ag···Ag distance of 3.0587(17)Å . These dimeric units are further doubly bridged by two nitrato ligands into a one-dimensional polymeric chain. The nitrato ligand exhibits an uncommon bidentate bridging mode of Ag-ONO-Ag. The title complex features a hydrogen bonded two-dimensional supramolecular framework formed via N-H···O hydrogen bonds, involving the uncoordinated O atom of the nitrate ligand and amine hydrogen atoms of aepy. The thermal stability of the title complex was investigated using thermogravimetry and differential thermal analysis.
New Route of Preparation and Properties of NaNiO2
Authors: Sofin Mikhail , Jansen Martin
Published: August 2018

NaNiO2 was prepared through oxidation of a Na2NiO2/ NiO mixture (1:1) in dried oxygen at 500 °C. Single crystals have been grown by annealing of NaNiO2 powder at 600 °C for 83 d in a flow of dried oxygen. According to the X-ray analysis of the crystal structure (C2/m, Z = 2, a = 5.3177(2), b = 2.8458(1), c = 5.5819(3) Å , β = 110.409(2)°, R1(all) = 3.4%, 185 independent reflections), the Jahn-Teller distorted NiO6 octahedra, sharing edges, build up layers lying parallel to the ab plane. A phase transition (associated with an energy of 2.9 kJ/mole) to a high temperature rhombohedral form (R3̅m, Z = 3, a = 2.958(1), c = 15.748(2) Å , at 300 °C) was observed by Guinier and DSC measurements at 195 °C. The magnetic susceptibility of the monoclinic phase can be described by the Curie-Weiss law between 100 and 330 K: μ = 2.01μB (g = 2.32), Θ = 37 K, indicating the dominance of ferromagnetic interactions of S = 1/2 spins within the NiO2 layers. Antiferromagnetic interlayer interactions produce an overall antiferromagnetically ordered structure below 18 K.
Exchange Interaction in a Dinuclear Iron(III) Complex of a Heptadentate Schiff Base: Synthesis, Crystal Structure and Magnetic Properties
Authors: Zeyrek C. T. , Elmali A. , Elerman Y.
Published: August 2018

Synthesis, crystallographic characterization and magnetic properties of the new dinuclear iron(III) complex Fe2L(OCH3)Cl2 (L=1,3-bis[N-(3,5-dichloro-2-hydroxybenzylidene)-2-aminoethyl]-2-(3,5- dichlo ro-2-hydroxyphenyl)imidazolidine) are reported. The structure consists of dinuclear units. The two iron(III) atoms are asymmetrically bridged by a phenoxo and a methoxo group. The iron(III) centers are separated by 3.133(2) Å . The Magnetic susceptibility of the complex was measured over the range 5 - 298 K and the observed data were successfully simulated by the equation based on the spin-Hamiltonian operator H = −JS⃗1.S⃗2. Magnetic susceptibility measurements indicate very weak antiferromagnetic coupling between the iron ions with J = −10.8 cm−1 and g = 2.0.
Synthesis and Structural Characterization of a New Two-Dimensional Polymeric Thallium(I) Complex, [Tl2(phthalate)]n
Authors: Fadaei M. R. , Morsali A. , Mahjoub Ali R.
Published: August 2018

Determination of the structure of the [Tl2(phthalate)] by X-ray crystallography shows that there are six (TlO6) and five (TlO5) coordinate Tl atoms. The complex is a two-dimensional coordination polymer.
Isolation, Characterization and Crystal Structure of Cytotoxic ent-Kaurane Diterpenoids from Isodon weisiensis C.Y. Wu
Authors: Ding Lan , Zhang Zhang-Jing , Liu Guo-An , Yang Dong-Juan , Guo Guo-Cong , Wang Han , Sun Kun
Published: August 2018

The new ent-kaurane diterpenoid weisiensin C (1) (1α,7α,14β ,18,20-pentahydroxy-ent-kaur-16- en-15-one), together with four known ent-kaurene diterpenoids, glaucocalyxin A (2), kamebanin (3), macrocalyxin D (4), and excisanin K (5), was isolated from the leaves of Isodon weisiensis C.Y. Wu. The structure of the new constituent (1) was elucidated by spectroscopic methods and confirmed by single-crystal X-ray diffraction.
Three Sesquiterpenoids, Fascicularones E, F, and G Produced by the Fungus Hypholoma fasciculare
Authors: Shiono Yoshihito , Akasaka Hironari , Hiramatsu Fuminori , Sato Kozue , Murayama Tetsuya , Ikeda Michimasa
Published: August 2018

Three new sesquiterpenoids, fascicularones E, F, and G, were isolated from the liquid culture extract of the fungus Hypholoma fasciculare. Their structures were established based on spectroscopic data.
New Eremophilane-Type Sesquiterpenoids, Eremoxylarins A and B from Xylariaceous Endophytic Fungus YUA-026
Authors: Shiono Yoshihito , Murayama Tetsuya
Published: August 2018

Two new eremophilane sesquiterpenes, eremoxylarins A and B, were isolated from the xylariaceous endophytic fungus YUA-026. Their structures were determined by spectroscopic methods. Eremoxylarins A and B showed antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa.
Synthesis of Some New Linear and Chiral Macrocyclic Pyridine Carbazides as Analgesic and Anticonvulsant Agents
Authors: Amr Abdel-Galil E.
Published: August 2018

A series of 2,6-disubstituted pyridine derivatives were prepared from 2,6-diacetylpyridine or 2,6- dicarbonyl pyridine dichloride as starting materials. Reaction of 2,6-diacetylpyridine 1 with hydroxylamine hydrochloride or different aromatic aldehydes afforded the corresponding 2,6-diacetylpyridine dioxime and 2,6-bis-[β -(2-thienyl)acryloyl]pyridine derivatives 2 and 3, respectively. Additionally, N2,N2‘-(pyridine-2,6-dicarbonyl)-L-amino acid hydrazides 5 were prepared starting from 2,6- dicarbonyl pyridine dichloride via the corresponding esters 4. Compound 3 was reacted with hydroxylamine hydrochloride to afford the 2,6-bis-[β -(2-thienyl)acryloyl-oxime]-pyridine derivative 6. Treatment of compounds 2 or 6 with phenyl isocyanate or phenyl isothiocyanate in refluxing dioxane gave the corresponding semicarbazide or thiosemicarbazide derivatives 7 and 8, respectively. Their treatment with toluene-3,5-diisocyanate afforded the macrocyclic semicarbzides 9 and 10, respectively. The chiral thiosemicarbazides 11a,b were however, prepared by treating compounds 5a,b with phenyl isothiocyanate followed by cyclization with sodium hydroxide (2N) yielding the triazoles 12a,b. Finally, the hydrazides 5a,b were treated with toluene-3,5-diisocyanate to afford the chiral macrocyclic tetrapeptide semicarbazides 13a,b in reasonable yields, while the expected cyclic dipeptide 14 was not formed. The structure assignments of the new compounds were based on chemical and spectroscopic evidence.

The pharmacological screening showed that many of these compounds have good analgesic and anticonvulsant activities comparable to Voltarine® and Carbamazapine® used as reference drugs.
Eupatoric Acid: A Novel Triterpene from Eupatorium odoratum L. (Asteraceae)
Authors: Amatya Sajan , Tuladhar Sarbajna M.
Published: August 2018

Phytochemical studies on the petroleum ether extract of the roots of Eupatorium odoratum have resulted in the isolation of a novel triterpene, 3β -hydroxy-28-carboxyolean-12-ene (1) along with seven known compounds - poriferasterol (2), octadecane (3), butyrospermol acetate (4), bis(2- ethylhexyl)phthalate (5), chrysophanol (6), physcion (7) and palmitic acid (8). Novel compound 1 is designated as eupatoric acid. Compounds 2 - 7 were reported here for the first time from this plant. Palmitic acid (8) was also isolated for the first time from this root. The structure of the novel compound was established on the basis of spectroscopic studies. The cytotoxicity of the compounds 1 - 7 was studied using a lethality test against Artemia salina (brine shrimp).
Guaianolide and seco-Guaianolide from Salvia nubicola (Lamiaceae)
Authors: Ali Muhammad Shaiq , Ahmed Waqar , Ibrahim Syed Amir
Published: August 2018

A sesquiterpene-lactone of the guaianolide class (nubenone) and a seco-guaianolide (nubenoic acid) have been isolated from Salvia nubicola collected in Quetta, Pakistan. Structures of both sesquiterpenes were elucidated with the aid of spectroscopic techniques including two dimensional NMR spectroscopy.
A New Marasmane Sesquiterpene from the Basidiomycete Russula foetens
Authors: Wang Xing-Na , Wang Fei , Du Jian-Chang , Ge Hui-Ming , Tan Ren-Xiang , Liu Ji-Kai
Published: August 2018

A new marasmane sesquiterpene, named lactapiperanol E (1), was isolated from the fruiting bodies of Russula foetens together with a known sesquiterpene lactapiperanol A (2). Their structures were established on the basis of spectral methods (MS, IR, 1D and 2D NMR experiments).
Spasmolytic Action of Diplotropin, a Furanoflavan from Diplotropis ferruginea Benth., Involves Calcium Blockade in Guinea-Pig Ileum
Authors: Lima Julianeli T. , Almeida Jackson R. G. S. , Barbosa-Filho José Maria , Assis Temilce S. , Silva Marcelo S. , da-Cunha Emídio V. L. , Braz-Filhod Raimundo , Silva Bagnólia A.
Published: August 2018

Diplotropis ferruginea Benth. (Fabaceae) is a tree popularly known in Northeastern Brazil as “sucupira-preta”. In the present work, the isolation, identification and pharmacological activity of a furanoflavan-type flavonoid (2,3-trans-3,4-trans)-3,4,5,8-tetramethoxy-(6,7,2”,3”)-furanoflavan, which received the trivial name diplotropin is reported. The structure was determined by means of spectroscopic techniques, especially EIMS and 1D and 2D NMR. Diplotropin (10−8 −3 · 10−4 M) inhibited the phasic contractions induced by both acetylcholine (IC50 = 4.6±0.8 · 10−5 M) and histamine (IC50 = 2.3±1.1 · 10−5 M) in guinea-pig ileum. Diplotropin relaxed the ileum pre-contracted with KCl (EC50 = 3.9±1.1 · 10−6 M), acetylcholine (EC50 = 3.7±1.6 · 10−6 M) and histamine (EC50 = 4.4±1.4 · 10−5 M) in a concentration-dependent manner. As the maintenance of tonic contraction induced by these contractile agents involves Ca2+ influx through voltage-dependent Ca2+ channels, it is suggestive that this relaxation may be due to the blockade of Ca2+ influx through those channels. This hypothesis was confirmed by the observation that diplotropin antagonized (pD’2 = 4.83±0.37) CaCl2 induced contractions in Ca2+-free depolarizing medium (IC50 = 1.5±0.8 · 10−5 M).
A Thermodynamic Study of the Charge Transfer Complexes of Iodine with Different tert-Butylcalix[4]crowns
Authors: Mizyed Shehadeh A. , Ashram Muhammad , Saymeh Riyadh , Marji Deeb
Published: August 2018

Formation of the charge-transfer complexes between calix[4]crowns (1 - 4) and iodine in chloroform solution was studied using UV-vis spectrophotometry. The stability constants and the thermodynamic data of the resulting 1 : 1 complexes were determined and was found to decrease with increasing the size of the crown moiety of the calixcrown. All complexes formed were found to be enthalpy stabilized, and all except the complex of 2 were entropy destabilized.
Synthesis, Crystal Structure and Thermal Properties of Copper(II) Orotato Complex with 2,2’-Bipyridine
Authors: Yeşilel Okan Zafer , Ölmez Halis , İçbudak Hasan , Büyükgüngör Orhan
Published: August 2018

A mixed-ligand orotato (HOr) complex of Cu(II) with 2,2’-bipyridine (bipy) was synthesized and characterized by elemental analysis, magnetic susceptibility, UV-vis and FT-IR spectroscopy, TG / DTA techniques and X-ray diffraction analysis. X-Ray diffraction analysis has shown that the squarepyramidal five-coordinate copper atom is chelated by the deprotonated N3 pyrimidine atom and the carboxylate oxygen atom of the bidentate orotato dianion, and to the two nitrogen atoms of the 2,2’- bipyridine molecule. A water molecule is attached above the N3O plane. Thermal analyses showed that the title compound decomposes in two steps over the range 20 - 1000 °C on heating in a static air atmosphere. Intermolecular hydrogen-bonds and π-ring interactions lead to the formation of a three-dimensional network.
Tyrosinase Inhibitor Fatty Ester and a Quinoline Alkaloid from Skimmia laureola
Authors: Sultana Nighat , Atta-ur-Rahman  , Khan Tariq H.
Published: August 2018

Aerial parts of Skimmia laureola yielded a new tyrosinase inhibitor fatty ester, (+)-skimmidiol (1), and a new alkaloid ribaliprenylene (2). The configuration at C-3’ in 1 was established by Horeau’s procedure. Compound 1 was screened for its enzyme inhibitory activity against tyrosinase (E.C.1.14.18.1), exhibiting activity with IC50 51.25±1.10165 μM.
A Dimeric Mn(III) Complex of a Quadridentate Schiff Base Ligand. Synthesis, Structure and Ferromagnetic Exchange
Authors: Balikesir Hulya Kara
Published: August 2018

The synthesis, crystal structure and magnetic properties of [Mn(III)L(H2O)]2(H2O)(ClO4) (1)(L = N,N'-bis(rac-5-chlorosalicylidenato)-1,2-diaminopropane) are reported. Compound 1 consists of a structurally dinuclear system in which two Mn ions are bridged by the oxygen atoms of μ-phenoxo ligands. Low temperature magnetic susceptibility measurements show a ferromagnetic intra-dimer interaction with J = +1.75 cm−1, g = 2.01 and α = −0.32.
Solvent-free Friedel-Crafts Reaction for Regioselective Synthesis of Ethyl (9-Anthryl)glyoxylate and Chiral Resolution of (±)-(9-Anthryl)hydroxyacetic Acid
Authors: Li Bao-Lin , Zhang Zhen-Guo , Wang Wei , Li Jin , Wang Chou-Wen
Published: August 2018

A green chemistry-based highly regioselective synthesis of ethyl (9-anthryl)glyoxylate was achieved by solvent-free Friedel-Crafts reaction at r. t. Several derivatives of ethyl (9-anthryl)glyoxylate were also synthesized. Ethyl (9-anthryl)hydroxyacetate was obtained almost quantitatively by reduction of ethyl (9-anthryl)glyoxylate with NaBH4, and (9-anthryl)methoxyacetic acid was prepared by methylation of ethyl (9-anthryl)hydroxyacetate with CH3I in the presence of Ag2O and hydrolysis of ethyl (9-anthryl)methoxyacetate. The hydrolysis of ethyl (9-anthryl)hydroxyacetate gave racemic (9-anthryl)hydroxyacetic acid, and the racemate was successfully resolved by crystallization of the diastereomeric salts resulting from the reaction of (±)-(9-anthryl)hydroxyacetic acid with (-)-ephedrine. As a byproduct, crystals containing racemic (±)-(9-anthryl)hydroxyacetate and protonated (-)-ephedrine were isolated and their structures determined by X-ray diffraction.
A New Chlorine-containing Sesquiterpene Lactone from Achillea ligustica
Authors: Hegazya Mohamed-Elamir F. , Mohamed Abou El-Hamd H. , El-Sayed Magdi A. , Ohta Shinji
Published: August 2018

Chromatographic investigation of the methylene chloride/methanol extract of the aerial parts of Achillea ligustica afforded a new chlorine-containing sesquiterpene lactone as well as two known compounds. The structures of the compounds were determined by comprehensive NMR studies, including DEPT, COSY, NOE, HMQC, HMBC and HRMS. The neurotrophic activity of the new compound has been measured.
Ab initioMolecular and Solid State Studies of the FeII Spin Cross-over System [Fe(btz)2(NCS)2] (btz = 2.2’-bis-4.5-dihydrothiazine)
Authors: Kabalan Lara , Matar Samir F. , Zakhour Mirvat , Létarda Jean François
Published: August 2018

Ab initio computations within the density functional theory are reported for the spin cross-over complex [Fe(btz)2(NCS)2] (btz = 2.2'-bis-4.5-dihydrothiazine), where 3d6 FeII is characterized by high-spin (HS t2g
4, eg
2) and low-spin (LS t2g
6, eg
0) states. Results of infrared and Raman spectra for the isolated molecule are complemented for the crystalline solid with a full account of the electronic band structure properties: the density of states assessing the crystal field effects and the chemical bonding, assigning a specific role to the Fe-N interactions within the coordination sphere of FeII
Oxygen Excess in La2CoO4+δ : A Neutron Diffraction Study
Authors: Aguadero Ainara , Alonso José Antonio , Daza Loreto
Published: August 2018

The layered perovskite La2CoO4+δ has been prepared and characterized in order to identify its capability of incorporating interstitial oxygen atoms (δ ) and their effect on the crystal structure. The synthesis has been performed by a citrate-nitrate soft-chemistry technique; a high oxygen pressure treatment (350 °C, 200 bar) has allowed us to increment the interstitial oxygen contents up to δ = 0.32(1). The samples have been characterized by thermal analysis (TG and DTA), X-ray diffraction at room temperature and neutron diffraction at temperatures up to 600 °C. At r. t., the as-prepared phase, La2CoO4.22(1), is orthorhombic, space group Bmab, with an important orthorhombic strain, if compared with La2NiO4+δ . At high temperatures it undergoes two consecutive structural transitions, to an orthorhombic superstructure at 375 °C and finally to a tetragonal symmetry (space group F4/mmm) at 590 °C. The phase La2CoO4.32(1) seems to represent a superstructure with orthorhombic symmetry and with a doubled b unit-cell parameter with respect to the prepared sample.
Structures and Thermal Properties of Silver(I) (Poly)chalcogenide Halide Solid Solutions Ag10Te4–(q, p)Q(q, p)Br3 with Q = S, Se
Authors: Nilges Tom , Bawohl Melanie
Published: August 2018

X-Ray diffraction experiments, thermal analyses and EDX spectroscopy were performed to determine the structural and thermal properties of the solid solutions Ag10Te4−qSqBr3 and Ag10Te4−pSepBr3. The present investigation completes the work on silver(I) (poly)chalcogenide halides, a new class of mixed electron and ion conductors, with the general composition Ag10Q4X3 (Q = chalcogen and X = halogen). A high silver mobility within the polytelluride substructure and a pronounced polymorphism are characteristic features of these solid electrolytes. Phase transition temperatures are reduced upon the substitution of Te by the lighter homologs Se and S. Even low degrees of substitution lead to significantly lower phase transitions for the high-temperature polymorphs compared with Ag10Te4Br3. A permanent disorder within the silver substructure is present for the maximally substituted sulfur containing phases.
Polymorphism of Ba1–xSrxCoO3–δ (0≤ x≤ 1) Perovskites: A Thermal and Structural Study by Neutron Diffraction
Authors: de la Calle Cristina , Alonso José Antonio , Fernández-Díaz Maria Teresa
Published: August 2018

The preparation of different hexagonal, orthorhombic and cubic polymorphs of the solid solution Ba1−xSrxCoO3−δ (0 ≤ x ≤ 1) is described. The samples have been studied by thermal analysis (TG and DTA) to identify the phase transitions; the thermal structural evolution and the structural characterization of different phases were analyzed by X-ray and neutron powder diffraction and refined by the Rietveld method. A series of hexagonal perovskites Ba1−xSrxCoO3−δ (0 ≤ x < 0.5), labelled as “H”, were synthesized by thermal treatment of reactive citrate precursors at 900 °C in high oxygen pressure followed by slow cooling to r. t. The hexagonal perovskites with 0.5 ≤ x ≤ 1 were obtained from the citrate precursors heated twice at 900 °C in air and slowly cooled in the furnace. Orthorhombic brownmillerite-like structures, labelled “O”, were obtained from precursors with composition 0.5 ≤ x ≤ 1 by quenching in liquid N2 from 900 °C. For x < 0.5, quenching from high temperatures does not stabilize the “O” phases. The crystal structure for both terms of the solid solution (x = 0 and x = 1) has been investigated by neutron powder diffraction. DTA and X-ray thermo-diffractometry show that “H” phases experience a reconstructive transition at ca. 900 °C to give cubic “C” polymorphs.
Electronic Structure and Chemical Bonding within MgB2 and Related Borides from First Principles
Authors: Matar Samir F.
Published: August 2018

The electronic structures of actual and hypothetical binary borides AB2 (A = Al, Mg, Li, Be, Ca) and of mixed hypothetical phases A'MgB4 (A' = Al, Li) are obtained and analyzed within the density functional theory using pseudo-potential and all-electron methods (VASP and ASW) in order to address the changes in the electronic structure within the high-temperature superconductor MgB2 by modeling isoelectronic and n/p-doping effects. From the properties of quantum mixing between respective valence states and of chemical bonding we propose an analysis of the high-temperature superconductivity within the two models, the classical one of Bardeen, Cooper and Schrieffer (BCS) and the hole superconductivity model, which is based on experimental and calculated results from the literature.
High-pressure / High-temperature Studies on the Stannides RENiSn (RE = Ce, Pr, Nd, Sm) and REPdSn (RE = La, Pr, Nd)
Authors: Riecken Jan F. , Heymann Gunter , Hermes Wilfried , Rodewald Ute Ch. , Hoffmann Rolf-Dieter , Huppertz Hubert , Pöttgen Rainer
Published: August 2018

The normal-pressure (NP) orthorhombic TiNiSi-type (space group Pnma) stannides RENiSn (RE = Ce, Pr, Nd, Sm) and REPdSn (RE = La, Pr, Nd) were transformed into the corresponding hexagonal ZrNiAl-type (space group P6̄2m) high-pressure (HP) modifications under multianvil high-pressure (7.5 - 11.5 GPa) high-temperature (1100 - 1200 °C) conditions. The structures of NP-CeNiSn, HPPrNiSn, NP-NdNiSn, HP-LaPdSn, HP-PrPdSn, and HP-NdPdSn were refined from single crystal X-ray diffractometer data. Structural data for HP-SmNiSn were obtained from a Rietveld powder refinement. The high-pressure phase transition significantly changes the rare earth coordination, i. e. 4 RE + 6 Ni(Pd) + 6 Sn atoms for the NP-phases and 6 RE + 5 Ni(Pd) + 6 Sn atoms for the HPphases. Susceptibility measurements of HP-PrPdSn and HP-NdPdSn reveal paramagnetic behavior with experimental magnetic moments of 3.61(1) μB/Pr atom and 3.66(1) μB/Nd atom, respectively. Low-temperature susceptibility and specific heat data point to inhomogeneous magnetism and spinglass behavior, respectively.
Solvothermal Synthesis of Co-doped ZnO Nanopowders
Authors: Fidelus Janusz , Piticescu Radu Robert , Piticescu Roxana Mioara , Lojkowski Witold , Giurgiu Liviu
Published: August 2018

Results are presented on the microwave solvothermal synthesis of Co-doped ZnO powders starting from zinc and cobalt acetate precursors in ethylene glycol solutions. The method yields powders with a relatively high degree of agglomeration of initially nucleated nanometer grains. It has been demonstrated that the thermodynamic estimations of the final composition using the Gibbs calculation method are in good agreement with experimental values for the chemical composition in a range of cobalt concentrations up to 15 mol-%
Synthesis of Nano-sized Yttrium-Aluminum Garnet in a Continuous-Flow Reactor in Supercritical Fluids
Authors: Chudoba Tadeusz , Lester Edward , Łojkowski Witold , Poliakoff Martin , Li Jun , Grzanka Ewa , Presz Adam
Published: August 2018

The conditions for obtaining pure yttrium-aluminum garnet (YAG) in a one-step process starting from components soluble in supercritical (SCR) liquids in a flow reactor have been studied. The powders were characterized using XRD, BET, SEM and helium pycnometry. Favorable conditions for YAG production were achieved using acetates (and acetylacetonates) in aqueous-alcoholic solutions as starting materials. Aqueous and alcoholic solutions of nitrates and aqueous solutions of acetates were found not appropriate as precursors for YAG production. The powders obtained had the shape of nano-sized cubes with diameters in the range 80 - 120 nm. After annealing at 600 °C the powders have comparable density as those made via a conventional precipitation-calcination route but differ from the calcinated products form soft agglomerates.
A New Supramolecular Assembly Obtained by Reaction Between Thiosaccharin and Pyridine
Authors: Piro Oscar E. , Zinczuk Juan , Baran Enrique J.
Published: August 2018

The crystal structure of pyridinium thiosaccharinate thiosaccharin, [HNC5H5]+ [(tsac)(Htsac)]− (Htsac = C7H5NO2S2, the thiosaccharin molecule), was determined by single-crystal X-ray diffraction. Both, the thiosaccharinate anion, the corresponding neutral molecule and the pyridinium cation are nearly planar and arranged in the solid state in an almost parallel fashion, hence giving rise to a layered supramolecular structure. The anion shows small but significant modifications in the bonding of the thioamide group as compared with the neutral molecule. The crystal is further stabilized by an extensive H-bonding network. The FTIR spectrum of the compound is briefly commented.
Brevifoliasaponin with Adjuvant Activity from Calliandra brevifolia
Authors: Barbosa Antony P. , da Silva Bernadete P. , Parente José P.
Published: August 2018

A new complex triterpenoid saponin, brevifoliasaponin, was isolated from leaves of Calliandra brevifolia Benth. (Leguminosae) by using chromatographic methods. Its structure was established as 3-[(O-α-L-arabinopyranosyl-(1 → 2)-O-α-L-arabinopyranosyl-(1 → 6)-2-(acetylamino)- 2-deoxy-β -D-glucopyranosyl)oxy]-16-hydroxy-(3β ,16α)-olean-12-en-28-oic acid O-β - D-xylopyranosyl-(1 → 3)-O-β -D-xylopyranosyl-(1→4)-O-[β -D-glucopyranosyl-(1 → 3)]-O-6-deoxy- α-L-mannopyranosyl-(1 → 2)-6-O-[(2E,6S)-6-[[2-O-[(2E,6S)-6-[[2-O-[(2E,6S)-2,6-dimethy- l1-oxo-6-(β -D-xylopyranosyloxy)-2,7-octadienyl]-β -D-xylopyranosyl]oxy]-2,6-dimethyl-1-oxo- 2,7-octadienyl]-β -D-xylopyranosyl]oxy]-2,6-dimethyl-1-oxo-2,7-octadienyl]-β -D-glucopyranosyl ester. Its structural elucidation was performed using detailed analyses of 1H and 13C NMR spectra including 2D-NMR spectroscopic techniques and chemical conversions. The hemolytic activity of the saponin was evaluated using in vitro assays, and its adjuvant potential on the cellular immune response against ovalbumin antigen was investigated using in vivo assays.
Two New Oleanane-type Triterpenoids from Buddleja asiatica
Authors: Liu Ya-Ping , Cai Xiang-Hai , Du Zhi-Zhi , Li Wei-Qi , Luo Xiao-Dong
Published: August 2018

Two new oleanane-type triterpenoids, 13,28-epoxy-23-hydroxy-11-oleanene-3-one (1) and 13,28- epoxy-21β ,23-dihydroxy-11-oleanene-3-one (2), along with seven known compounds, have been isolated from the aerial parts of Buddleja asiatica Lour. All structures were elucidated by spectroscopic techniques (NMR, MS, UV, and IR).
A One-dimensional Double-chain Compound Constructed from CeIII Cations and [α-SiW11O39]8- Anions: Synthesis, Crystal Structure and Magnetic Properties
Authors: Hu Mi-Xia , Chen Ya-Guang , Shi Dong-Mei , Pang Hai-Jun , Zhang Chun-Jing
Published: August 2018

A polyoxometalate compound consisting of monovacant Keggin anions and trivalent lanthanide cations, K2H2{Ce(H2O)6[Ce(H2O)2(α-SiW11O39)]}2·26H2O (1), has been synthesized and characterized by elemental analysis, IR and UV spectroscopy, TG analysis, and single crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system with space group P1̄. The coordination of the monovacant Keggin anions and the Ce3+ ions creates a double-chain structure. The K+ cations link the double-chains to form corrugated layers, and the layers are further connected into a 3D architecture through hydrogen bonds. A variable temperature magnetic study indicates antiferromagnetic coupling in compound 1.
Two New Ruthenium(II) Complexes with Cyclometalated 2-Phenylpyridine Ligands
Authors: Maas Gerhard , Schäffler Lutz , Buck Stefan
Published: August 2018

The reaction of Ru3(CO)12 and 2-phenylpyridine (Hppy) in hot methanol yields the dinuclear ruthenium(II) complex [Ru(OCH3)(ppy)(CO)2]2 (3) in moderate yield. Heating of Ru3(CO)12 and Hppy in a cyclohexane-dimethoxyethane mixture generates the mononuclear complex [Ru-cis- (ppy)2-cis-(CO)2] (2). When 2 is treated with methanol at elevated temperature, only partial conversion into 3 can be achieved. The structures of complexes 2 (two polymorphs) and 3 were established by X-ray diffraction analysis.
Stabilisierung des reaktiven Methylcarbonat-Ions im Kronenether- Komplex [Cs(18-Krone-6)(CH3CO3)] und dessen Hydrolyseprodukt / Stabilization of the Reactive Methylcarbonate Ion in the Crown Ether Complex [Cs(18-crown-6)(CH3CO3)], and its Hydrolysis Product
Authors: Jonušaite Adelė , Adam Arnold
Published: August 2018

[Cs(18-crown-6)(CH3CO3)] (1) has been obtained by the reaction of CsOCH3 with 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) in methanol in a CO2 atmosphere. The compound crystallizes in the monoclinic space group P21/n (no. 14) with a = 12.141(3), b = 8.610(1), c = 17.985(4) Å , β = 91.17(2)° and V = 1879.6(7) Å3. Cs is tenfold coordinated by six oxygen atoms of the crown ether and four oxygen atoms of two methyl carbonate anions which act as bidentate ligands. The slow hydrolysis of the methylcarbonate results in the hydrogencarbonate complex {Cs2(18-crown- 6)2 · [H2(CO3)2] · H2O · CH3OH} (2), the basic structural constitution of the starting material being retained. This new compound crystallizes in the monoclinic space group P21/c with a = 8.657 (7), b = 22.601 (2), c = 19.619 (15) Å, β = 92.09 (6)° and V = 3836.5 (6) Å3.
Materials with ZrCuSiAs-type Structure
Authors: Pöttgen Rainer , Johrendt Dirk
Published: August 2018

The discovery of high-temperature superconductivity in the fluoride-doped arsenide oxides REFeAs(O1−xFx) (RE = early rare earth element) with transition temperatures as high as 55 K has led to a true renaissance in superconductivity research. These arsenide oxides constitute a rather small fraction of a much larger family of compounds with the tetragonal ZrCuSiAs-type structure (space group P4/nmm), among them pnictide oxides and fluorides, chalcogenide oxides and fluorides as well as silicide and germanide hydrides. Besides the spectacular superconductivity, these materials have further interesting properties with respect to magnetic ordering, transparent semiconducting behavior or optical properties. The crystal chemical and chemical bonding peculiarities as well as the broadly varying physical properties are reviewed herein.
Reactions of 5(4H)-Oxazolones with Wittig-Horner Reagents: Novel Synthesis of Dioxopyrrolidinephosphonates and Phosphonoalkanoates with Anticipated Schistosomicidal Activity
Authors: Boulosa Leila S. , Arsanious Mona H.N. , Ewies Ewies F. , Ramzy Fatem
Published: August 2018

4-Benzylidene-2-phenyl-5(4H)-oxazolones react with Wittig-Horner reagents in the presence of alcoholic sodium alkoxide to give novel dioxopyrrolidinephosphonates, diethyl [3-(benzoylamino)- 1-cyano-2-oxo-4-phenylbut-3-en-1-yl]phosphonate and phosphonoalkenoate derivatives. Both the phosphonate adducts and the ester products were also isolated from the reaction of oxazolones with triethyl phosphonoacetate using alcoholic sodium ethoxide and/or sodium hydride as a base. Possible reaction mechanisms are considered, and the structural assignments are based on analytical and spectroscopic results. The biological evaluation of the new compounds is reported.
Photophysics of Ochratoxin A in Aqueous Solution
Authors: Steinbrück Dörte , Rasch Claudia , Kumke Michael U.
Published: August 2018

The photophysics of Ochratoxin A (OTA) in aqueous solution strongly depends on the pH. Due to its molecular structure OTA is prone to an excited state proton transfer reaction, which rules the photophysical properties. Based on results of absorption and fluorescence measurements the rate constants of the proton transfer reactions (forward and back reaction) were determined and subsequently, the pK*
a value was calculated. Based on the results, optimized experimental conditions for the analysis can be determined e. solvent conditions (HPLC chromatography) or excitation and emission wavelength (fluorescence spectroscopy).
Structure and Fluorescence Properties of a Novel Supramolecular Zinc Complex
Authors: Chen Gang
Published: August 2018

Hydrothermal reaction of Zn(NO3)2 · 6H2O and 2-hydroxypyridine-3-carboxylic acid afforded a novel supramolecular complex, [Zn(C6H4NO3)2(H2O)2] (1). The complex has been characterized by macroanalysis, IR spectra, and thermogravimetric and differential thermal analysis (TG/DTA). Single crystal X-ray analysis shows that complex 1 crystallizes in the monoclinic space group P21/c with the cell dimensions a = 7.534(6), b = 12.289(1), c = 7.534(6) Å, β = 100.51°, V = 685.85(1) Å3, and Z = 2. The six-coordinated Zn atom is in a severely distorted octahedral geometry. The complex molecules are assembled via strong O-H· · ·O and N-H· · ·O hydrogen bonding interactions into a three-dimensional supramolecular framework. Compared with the free ligand, complex 1 exhibits strong fluorescence in the solid state at room temperature.
Study of the [Zn(H2O)4CuEDTA]·2H2O Complex, a Potential Trace-metal Supplier: Synthesis, Crystal Structure, Spectroscopic Behavior and Metal Release
Authors: Santi Eduardo , Baran Enrique J. , Ellena Javier , Nascimento Otaciro R. , Torre María H.
Published: August 2018

Ethylenediaminetetraacetic acid (H4EDTA) is widely used in the pharmaceutical and bromatological industries and as a drug in chelation therapies. Besides, coordinated with metal ions it is used for the supplementation of essential trace elements. In this work the synthesis, crystallographic, and spectroscopic studies (EPR, IR, UV/Vis) of [Zn(H2O)4CuEDTA] · 2H2O are reported. The release of the metal cations at gastric pH was also investigated.
Syntheses, single-crystal structure determination, and Raman spectra of Rb[C(CN)3] and Cs[C(CN)3]
Authors: Reckeweg Olaf , Schulz Armin , DiSalvo Francis J.
Published: August 2018

Extracting residues of an aqueous solutions containing equimolar amounts of K[C(CN)3] and RbF or CsF, respectively, with absolute ethanol, yields triangular, transparent colorless crystals of Rb[C(CN)3] and Cs[C(CN)3] after the ethanol was allowed to evaporate. The compounds are isotypic and crystallize isopointal to calcite in space group R3̅c (no. 167) with the cell parameters a=809.9(1) and c=1461.3(3) pm and a=843.29(9) and c=1459.9(2) pm, respectively. Single crystals were used to record the Raman spectra of the title compounds.
Freie und Membrangebundene Ribosomen in der Rattenleber: Tagesrhytmik und hormonale Einflüsse / Free and Membrane-bound Ribosomes in Rat Liver: Daily Rhythm and Hormonal Influences
Authors: Dieminger Lothar
Published: August 2018

Free and membrane-bound ribosomes were isolated from rat liver and quantitized by photometric methods. The amount of membrane-bound ribosomes remaines relatively constant over 24 hours whereas the amount of free ribosomes changes considerably: a maximum appears between 6-9 h, a minimum between 18-21 h. Fasting the animals increases the overall variance.

Injections of cortisol 4 hours before killing the animals increases the total amount of ribosomes and induces a definite maximum of membrane-bound ribosomes at 6 h. The maximum of free ribosomes appears at the same time as in control animals. In contrast to cortisol, corticosterone has no effect on the total amount of ribosomes, it induces, however, a maximum of membrane-binding between 18-21 h. Also in this case the maximum of free ribosomes remains unchanged.

In the evening, the protein content of free ribosomes decreases whereas a change was not observed in membrane-bound ribosomes. Cortisol increases the protein content in free and membrane- bound ribosomes.
Ein Screening System zur Bestimmung einer Hemmung spezifischer Enzyme der DNS-Synthese und DNS-Reparatur / A Screening System to Determine Inhibition of Specific Enzymes of the Semiconservative DNA -synthesis and DNA-repair Replication
Authors: Kocsis F. , Klein W. , Altmann H.
Published: August 2018

To observe the influence of substances on specific enzymes of the semiconservative DNA- synthesis and DNA-repair replication a screening system was developed, which represents an extensive modification of known papers. Optimal conditions were found after comprehensive investigations. The detergens Tween 80 and the antileukemic drug cis-platinum(II)diammino- dichloride were used as test substances.
The Effect of Tetrodotoxin, Veratridine and Tetraethylammonium Chloride on the Receptor Potential of the Crayfish Photoreceptor Cell
Authors: Stieve H. , Malinowska T.
Published: August 2018

The effect of three drugs on the receptor potential (ReP) of the crayfish retina measured with external electrodes was tested.

1. Tetrodotoxin (TTX) (1·10-6 g/ml and 1·10-5 g/ml) showed only slight effects on the receptor potential (Table I and II).

2. Veratridine (VERA) (1·10-5 g/ml) showed only small effects of the same type as TTX but a little stronger on the receptor potential which became obvious especially in the period after washing out the drug (Table III).

3. Tetraethylammonium (TEA) (5 mм/1) caused a decrease of the height of the receptor potential without influencing the repolarizing phase (decrease-time £2) markedly (Table IV).

The results can be interpreted as follows:

1. The permeability increase for sodium, calcium and magnesium, whidi causes the rising phase of the receptor potential in the crayfish photoreceptor cell is of different nature than the increase of the sodium permeability in the squid nerve, or the sites of the sodium channel are not accessible for the TTX in the photoreceptor cell. This is shown by the experiments with TTX and VERA.

2. AU the changes of the receptor potential which are caused by TEA can be explained by assuming that the permeability for potassium in the dark is lowered by TEA and that in the course of the normal receptor potential an increase of potassium permeability, which causes the decreasing repolarizing phase of the receptor potential, does not occur.
Tryptic Fragmentation of the Calcium Transport System in the Sarcoplasmic Reticulum
Authors: Migala A. , Agostini B. , Hasselbach W.
Published: August 2018

Two protein fragments with a molecular weight of 50-60 000 daltons are formed when the calcium transport ATPase of the SR is mildly digested with trypsin. The initial fragmentation of the ATPase does not interfere with calcium transport, calcium dependent ATPase activity and phosphoprotein formation. The decay of the initially formed protein fragments after prolonged tryptic digestion is accompanied by the decline of the rate of calcium uptake and the calcium concentrating ability while the activity of the calcium activated ATPase is reduced only moderately. The initial tryptic fragmentation does not give rise to any change in the morphological appearance in the SR membranes. After prolonged digestion brush border or smooth surface structures are observed depending on the agent used for negative staining.
Stimulierung von Kulturen embryonaler Rattenzellen durch Kälberserum. V. Verhalten der Inosit- und Cholinphospholipide / Stimulation of Embryonic Rat Cells by Calf Serum. V. Metabolism of Inositol- and Choline Phospholipids
Authors: Ristow Hans-Jürgen , Frank Werner , Fröhlich Margitta
Published: August 2018

Embryonic rat fibroblasts were accumulated in G1-phase by incubation in serum-free medium and subsequently stimulated by the addition of calf serum. Using 3H-inositol and 14C-choline as label for phospholipids, the following results have been obtained:

1. Within a few minutes after stimulation up to 20 per cent of total phosphatidyl 3H-inositol is released from the membranes of prelabelled cells. This could not be detected with 14C-choline- prelabelled phospholipids.

2. Incorporation of 3H-inositol into phosphatidyl inositol, but not the uptake into the acid-soluble cell pool, is increased 30 and 45 min after stimulation by a factor of 2.8 and 3.3 respectively. Incorporation of 14C-choline at that time is significantly lower (2.0 and 1.6 respectively).

3. Incorporation of 32P inorganic phosphate into the lipid fraction of stimulated cells is 8.9 times higher after 10 min as compared with the controls.
Furocoumarins from the Seeds of Citrus trifo liata L.
Authors: Guiotto A. , Rodighiero P. , Fornasiero U.
Published: August 2018

A detailed study of the furocoumarins present in the seeds of Citrus trifoliata L. revealed the presence of isopimpinellin, prangenin and prangenin hydrate in addition to the already reported bergapten and imperatorin. The amount of these compounds, referred to the starting dry material, were: Imperatorin 0.15%, bergapten 0.06%, whereas isopimpinellin, prangenin and prangenin hydrate were found in the order of less than 0.01%.
Der Einfluß von ʟ-Äthionin auf Blutungsrate und Ionentransport im Blutungssaft / The Influence of ʟ-Ethionine on Bleeding Rate and Ion Transport within the Bleeding Sap
Authors: Lorenz H.
Published: August 2018

The bleeding rate as well as transport of K+, NO3
- and PO4
--- within the bleeding sap of corn plants (Zea mays) has been studied in intervals after raising the nitrate concentration of the nutrient solution from 5 to 10 meq/1.

Acceleration of the exudation process in response to increased nitrate supply is accomplished after a lag phase. During this lag phase ʟ-ethionine causes a marked stimulation of bleeding sap exudation.

A very close correlation (coefficient of correlation r = 0,996) was found between bleeding rate and phosphate transport within the bleeding sap, whereas transport of K+ (r=0,868) and NO3
- (r=0,773) is not that closely correlated. Because phosphate is translocated to the Xylem after it has been metabolized in a series of organic phosphorous compounds it is concluded that the exudation process is primarily linked to oxidative phosphorylation in the root, which is apparently stimulated by ethionine after a lag period. Acceleration of respiratory chain phosphorylation may be brought about by increasing the amount of phosphate acceptors.
Chemiluminescence Arising from the Action of 1Δg-Molecular Oxygen on Chlorophyll-a
Authors: Fuhr Hartmut , Stauff Joachim
Published: August 2018

Singlet oxygen (1Δg) was generated by a microwave discharge and bubbled through a solution of chlorophyll-a in dibutylphtalate at approximately 10-20 torr. It not only excited the dye to its first singlet state but also produced oxidized species which generated a very long lasting weak chemiluminescence. From quenching experiments for the generation of the excited species could computer simulation.
Über die sogenannte denaturierende Wirkung von Elektrolyten und Nichtelektrolyten, geprüft an der von Konzentration und pH-Wert abhängigen Volumsveränderung des elastischen Gewebes / On the So-called Denaturing Effect of Electrolytes and Non-electrolytes Shown by the Volume Changes of the Elastic Tissue Depending on Concentration and pH
Authors: Winkler R.
Published: August 2018

The effects of the saccharides on the volume of elastin are primarily “dehydrating” or “osmotic” ones, those of J- and Cl- are primarily “electrostatic” ones, and the effect of urea is predominantly a “denaturing” one.
Optomotorische Reaktionen der Biene auf bewegte „Polarisations-Muster“ / Optomotor Eesponses of the Bee to Moving “ Polarisation-Pattems”
Authors: Kirschfeld Kuno
Published: August 2018

Optomotor turning reactions were induced in worker bees by means of moving “polarisationpatterns”. The responses appeared only when the stimulating light was confined to the short wavelength part of the spectrum, and when the E-vector directions of the polarisation filters of whidi the pattern was composed were at ±45° to the vertical for stimulation of the front region of the eye. Assuming that the polarisation sensitivity of the individual receptor is independent of the wavelength of the light, the experiments show that at least two of the known three different types of colour receptors contribute to the optomotor turning reaction. These results are in agreement with the assumption, that the retinula cell output of each ommatidium is superimposed before the correlation for movement detection between different ommatidial channels takes place.
Ribonuclease Present in Myxoviruses
Authors: Wiegers Klaus J.
Published: August 2018

Endoribonuclease splitting single-stranded poliovirus RNA is associated with virions of the myxoviruses fowl plague virus and Newcastle disease virus. These virions are devoid of deoxyribonuclease hydrolyzing single-stranded M 13 phage DNA and ribonuclease hydrolyzing doublestranded poliovirus RNA. The latter enzyme, however, is present in allantoic fluids of infected chick embryos from which the virions are obtained.
The Association between Purine Nucleosides and Benzene in Aqueous Solution, Studied by Proton Magnetic Resonance and Nuclear Overhauser Enhancements
Authors: Lüdemann Hans-Dietrich , Goldammer Eberhard v.
Published: August 2018

The dependence of the PMR spectra of three purine nucleosides (inosine, adenosine and deoxyadenosine) on temperature, concentration and addition of benzene (0.12 molal) has been investigated in aqueous solution. The interaction of benzene with the nucleosides is deduced from the spectra. Enthalpies of self association have been determined as 2.2± 0.1 kcal·mole-1 for dA and I. The corresponding values obtained for hetero association with benzene are 2.7 ± 0.2 kcal·mole-1 for dA and 2.3± 0.2 kcal·mole-1 for I. The formation of edge to face complexes is concluded. Additional evidence for this type of hetero association has been obtained from the concentration and solvent dependence of the nuclear Overhauser enhancements (NOE) of solutions of the nucleosides. The enhancement factors of aqueous solutions of dA and I depend on the concentrations of the nucleosides. In solutions containing I the NOE found previously in DMSO and the NOE observed in D2O differ significantly 1. The results obtained can be explained by a change of the average glycosyl torsion angle of approximately 10° to 15° in the two solvents.
Interaction of Actin and Myosin in the Absence and Presence of ATP
Authors: Dancker Peter , Hoffmann Marianne
Published: August 2018

The binding between F-actin and myosin has been studied by analyzing the amount of radio-actively labelled (by means of 14C-NEM) F-actin and myosin in the formed unsoluble actomyosin pellet after centrifugation of the reaction mixture. In the absence of ATP, the amount of actin bound to myosin varies, depending on the amounts of actin and myosin present, between 0.18 mg actin/mg myosin (2 actin units per 1 myosin molecule) and about 2 mg actin/mg myosin (each actin fibril only uncompletely saturated with myosin). In 0.03 ᴍ KCl ATP decreases, if at all, the affinity of actin towards myosin only slightly; but less actin is bound to myosin in the presence of MgATP and in low ionic strength, indicating that myosin is now more densily distributed over fewer actin fibrils leaving the rest of fibrils free. For precipitation of the total amount of myosin (myosin alone is soluble in MgATP) incomplete saturation of myosin with actin suffices; obviously actin promotes filament formation of myosin. The activation of myosin ATPase by actin depends in a similar manner as actin binding does on actin concentration, hence the enzymatic interaction between actin and myosin is accompanied by true actin-myosin binding. An actin-tropomyosin-troponin preparation, whose reduced viscosity is lower than that of F-actin and which consists of about 30% actin, activates myosin ATPase to the same extent as F-actin does. It competes with F-actin for the same binding sites on myosin and can in the presence of MgATP be displaced from myosin by those preparations of F-actin which have a strong tendency to become fully saturated with myosin. The activation of myosin ATPase by actin-tropomyosin-troponin is reduced after tryptic digestion of actin-tropomyosin-troponin, which affects, according to SDS gel electro­ phoresis, mainly two components of troponin with molecular weights of about 32 000 and 25 000, respectively.
Ketocarotinoide in den Früchten von Lonicera webbiana und Lonicera ruprechtiana / Ketocarotinoids of the Berries from Lonicera webbiana and Lonicera ruprechtiana
Authors: Rahman Anna-Katharina , Egger Kurt
Published: August 2018

The main pigments of red Lonicera berries are Rhodoxanthin and two hitherto unknown ketocarotinoids named Loniceraxanthin and Webbiaxanthin. The structural formula for Loniceraxanthin is established (2) and for Webbiaxanthin a structural formula is discussed (3).