bluuebunny/crossref_metadata_2025 huggingface dataset:
Aluminat-Pentelate(III) AI
2M2Al2O7 und AIIM2Al2O7 (AI = Rb, Cs; AII = Ba; M = As, Sb) / Aluminate-Pentelates(III) AI
2M2Al2O7 and AIIM2Al2O7 (AI = Rb, Cs; AII = Ba; M = As, Sb)
Authors: Emmerling Franziska , Reinhard Christian , Zimper Sabine , Röhr Caroline
Published: August 2018

The crystal structures of the title compounds, which were synthesized at temperatures between 500 and 850 °C via reaction of Al2O3, M2O3 and M2O5 (M = As, Sb) with the respective elemental alkaline and alkaline earth elements, have been determined by single crystal X-ray diffraction. The two isotypic compounds AI
2Sb2Al2O7(K2Sb2Al2O7 structure type, AI=Rb/Cs; trigonal, space group P3̄̅m1, a = 566.04(10)/570.23(8), c = 836.8(2)/888.0(2) pm, Z = 1, R1 = 0.0511/0.0461) contain double layers consisting of vertex-sharing tetrahedra [Al2O7], which are connected to ψ- tetrahedra SbO3 via common vertices. These double layers are stacked in identical orientation (AA sequence), while in the barium compound BaSb2Al2O7 (trigonal, space group R32, a = 545.5(7), c = 2377.3(12) pm, Z = 3, R1 = 0.0427) similar layers [Sb2Al2O7] are stacked in an ABC sequence. In the arsenic(III) aluminate Cs2As2Al2O7 (orthorhombic, space group Imm2, a = 546.9(3), b = 1003.81(16), c = 888.5(3) pm, Z = 2, R1 = 0.0313) the Al2O7 moieties are similarly connected via [AsO3] units, in this case not only forming layers, but a three-dimensional network. In the three antimonates, the A cations are not coordinated by the lone electron pairs of M(III), which are oriented towards the interior of the sheets, whereas in the arsenate the lone electron pairs play a significant role in the coordination of one of the two crystallographically independent Cs sites
Prenylated Flavonoids from the Root of Egyptian Tephrosia apollinea – Crystal Structure Analysis
Authors: Abou-Douh Ahmad M. , Ito Chihiro , Toscano Rubén A. , El-Baga Nariman Y. , El-Khrisy Ezz El-Din A. , Furukawa Hiroshi
Published: August 2018

Three complex 7-oxygenated-8-prenylflavones, (-)-semiglabrin and (-)-pseudosemiglabrin, which are diastereoisomers, and lanceolatin A have been isolated from the root of Tephrosia apollinea (Del.) Link (Leguminosae) growing in Southern Egypt, together with two phytosterols, stigmasterol and sitosterol. The structures of the isolated compounds have been elucidated by means of physical and several spectroscopic methods including UV, IR, 1H, 13C NMR, DEPT, 2D 1H-1H COSY, HSQC, HMBC experiments, and high resolution mass spectrometry (HR-MS), as well as some chemical transformations. The stereochemistry of the structures of (-)-semiglabrin and lanceolatin A have been confirmed by X-ray crystal structure analysis. The anticarcinogenic properties of the isolated compounds showed no inhibitory mechanisms concerning the initiation, promotion, and progression stage of carcinogenesis. Moreover, the in vitro antimicrobial activities of the root ethanolic extract are discussed
Synthesis and Crystal Structures of a New μ-Bis(tetradentate) Schiff Base Ligand and its Mononuclear Iron(III) Complex: Iron(III) Induced Imidazolidine Ring Hydrolysis of Binucleating Schiff Base Ligand
Authors: Zeyrek C. T. , Elmali A. , Elerman Y.
Published: August 2018

The μ-bis(tetradentate) ligand, [C27H26Cl3N4O4], H3L′, 1,3-bis[N-(5-chloro-2-hydroxybenzylidene)- 2-aminoethyl]-2-(5-chloro-2-hydroxyphenyl)imidazolidine and its mononuclear iron(III) complex, [Fe(L)](ClO4), L = N, N′-bis(5-chloro-2-hydroxybenzylidene)-triethylenetetramine have been synthesized and their crystal structures determined. Minimum energy conformations of the ligand were calculated (MOPAC, AM1) as a function of two torsion angles and the results compared with optimized crystal structure. The ligand (H3L′) reacts with Fe(ClO4)2 · 6H2O in aqueous methanol to form the mononuclear [Fe(L)](ClO4) complex with the imidazolidine ring cleaved by hydrolysis. The complex has an N4O2 donor atom set forming a distorted octahedral coordination geometry around the metal atom as established from a crystal structure determination. The terminal oxygen donor atoms occupy cis positions, and the remaining four nitrogen atoms (two cis amine and two trans imine) complete the coordination sphere.
Studies on the Thermolysis of Ether-Stabilized Lu(CH2SiMe3)3. Molecular Structure of Lu(CH2SiMe3)3(THF)(diglyme)
Authors: Rufanov Konstantin A. , Freckmann Dominique M. M. , Kroth Heinz-Jürgen , Schutte Stefan , Schumann Herbert
Published: August 2018

Lu(CH2SiMe3)3(THF)2 (2) decomposes slowly at room temperature with formation of Me4Si. In order to understand the mechanism of this elimination process, Lu(CH2SiMe3)3([D8]-THF)2 (1), Lu(CH2SiMe3)3(THF)(DME) (3), and Lu(CH2SiMe3)3(THF)(diglyme) (4) were prepared. The results of 1H NMR spectroscopic studies of the decomposition in solution exclude an α- as well as a β -H elimination mechanism and point towards a γ -H elimination. The molecular structure of 4 has been determined by single crystal X-ray diffraction.
3-Substituted Coumarins from the Twigs of Rhadinothamnus rudis ssp. amblycarpus
Authors: Girard Corinne , Roux Delphine , Muyard Frédéric , Colombain Michel , Tillequin François , Waterman Peter G. , Bévalota Françoise
Published: August 2018

The twigs of Rhadinothamnus rudis ssp. amblycarpus (Phebalium rude ssp. amblycarpum) yielded three new 3-substituted coumarins: rudicoumarin A-C (1- 3). Their structures were established on the basis of their NMR and mass spectral data. In addition, ten other known compounds were also isolated, including phebaclavin I, schinicoumarin, seselin, and seven linear furocoumarins.
Triterpenoids from Hippocratea excelsa. The Crystal Structure of 29-Hydroxytaraxerol
Authors: Aguilar-Gonzalez Amilcar R. , Mena-Rejón Gonzalo J. , Padilla-Montaño Nayely , Toscano Alfredo , Quijano Leovigildo
Published: August 2018

The root bark of Hippocratea excelsa afforded a new derivative of β -amyrin, which was identified as its ferulate, together with components new in this species. They were identified as the rare 29-hydroxytaraxerol, 29-hydroxyglutinol, 29-hydroxyfriedelin and the sterol 6β -hydroxystigmast-4- en-3-one. The known triterpene quinone methides pristimerin and tingenone characteristics of this genus, β -sitosterol, trans-polyisoprene, squalene, β -amyrin, and the alditol galacticol characteristic of the Celastraceae were also isolated. The structures were established on the basis of spectral analysis, including homo- and heteronuclear correlation NMR experiments (COSY, DEPT, HMQC and HMBC) and by comparison with data reported in the literature. The structure of 29-hydroxytaraxerol was confirmed by X-ray diffraction. The antimicrobial and antifungal activities of the compounds were studied, but no significant activity was found.
Dodekahydro-closo-Dodekaborat-Halogenide der schweren Alkalimetalle mit der Formel M3X[B12H12] (M = K – Cs, NH4; X = Cl und Br) / Dodecahydro-closo-dodecaborate Halides of the Heavy Alkali Metals with the Formula M3X[B12H12] (M = K – Cs, NH4; X = Cl and Br)
Authors: Tiritiris Ioannis , Weidlein Johann , Schleid Thomas
Published: August 2018

The solvent-free dodecahydro-closo-dodecaborate chlorides M3Cl[B12H12] (M+ = Rb+, Cs+) and bromides M3Br[B12H12] (M = K+ −Cs+, NH4
+) of the heavy alkali metals are easily accessible by recrystallization of the corresponding M2[B12H12] salts from aqueous solutions of the respective alkali-metal chlorides (MCl) or bromides (MBr). After precipitation colourless, polyhedralshaped single crystals were obtained and characterized by X-ray diffraction at room temperature. The compounds are all isostructural and crystallize in the trigonal space group R3̅m with Z = 3 (Rb3Cl[B12H12]: a = 1009.73(7), c = 1139.14(9) pm; Cs3Cl[B12H12]: a = 1038.02(7), c = 1179.59(9) pm; K3Br[B12H12]: a = 1002.34(7), c = 1117.68(9) pm; (NH4)3Br[B12H12]: a = 1015.61(7), c = 1138.70(9) pm; Rb3Br[B12H12]: a = 1016.89(7), c = 1141.82(9) pm; Cs3Br[B12H12]: a = 1045.53(7), c = 1185.47(9) pm). Their structures are best described as a trigonally distorted variant of an anti-perowskite arrangement, the anti-LaAlO3-type structure. Together, the quasi-icosahedral [B12H12]2− cluster anions and the M+ cations build up a cubic close-packed host structure where the halide anions (X−) occupy all those octahedral interstices which are exclusively formed by the cations. The thermal decomposition of the salts was investigated by thermal analysis with DTA/TG methods in the temperature range between 30 and 1200 °C. The solid salts were also characterized using IR and Raman spectroscopy. The observed splitting of the B−H and B−B absorption bands clearly indicates a loss of symmetry of the quasi-icosahedral dianionic [B12H12]2− clusters.
Cobalt Complexation with Unsymmetrical Tripodal Ligands
Authors: Jocher Christoph , Pape Tania , Hahn F. Ekkehardt
Published: August 2018

The reaction of the aliphatic unsymmetrical tripod [N(CH2CH2NH2)2(CH2CH2OH)], H5-1, with cobalt(II) chloride in THF yields after aerial oxidation the dinuclear complex [(H4-1)CoIII(μ-OH)CoIII(H4-1)](CoIICl4)Cl, [5](CoCl4)Cl. The trianion 53− contains two cobalt atoms triply bridged by two alkoxo groups of the singly deprotonated ligand (H4-1)− and a hydroxo group. The new ligand [N(CH2CH2CH2NH2)(CH2CH2OH)2], H4-3, providing an N2O2 donor set reacts with cobalt(II) chloride to give after aerial oxidation the hexanuclear complex [CoIII
4(H2-3)4CoII
2(HOMe)2Cl2(μ-OH)4], [6]Cl2, containing an unprecedented mixed-valent CoIII
4CoII
2 core.
First X-Ray Structures of Ethylene Bridged Neutral Dimeric Hexacoordinate Silicon Complexes with Tetradentate Salen-Type Ligands
Authors: Wagler Jörg , Roewer Gerhard
Published: August 2018

Syntheses and structures of two novel “doubledecker” silicon complexes [R-Si(o-O-p-OMe-C6H3- C(Ph)=N-(CH2)2-N=C(Ph)-C6H3-p-OMe-o-O)-CH2-]2 (R = Ph, p-tBu-C6H4-O) with the silicon atoms hexacoordinated by two salen-type tetradentate 〈ONNO〉-chelating ligands are described. Hydrogen bonding between the halves of the bridged complexes as well as with chloroform solvate molecules determines the conformation. Compared with analogous mononuclear silicon complexes these ”doubledeckers” show bathochromically shifted Vis-absorption.
Selten-Erd-Mandelate. Synthese und Kristallstrukturen von Pr(Man)3(ManH) und Er(Man)3(H2O)2 / Synthesis and Crystal Structures of Pr(Man)3(ManH) and Er(Man)3(H2O)2
Authors: Bromant Claudia , Nika Wassiliki , Pantenburg Ingo , Meyer Gerd
Published: August 2018

Pr(Man)3(ManH) and Er(Man)3(H2O)2 (ManH = mandelic acid) have been synthesized by slow evaporation of aqueous solutions of rare-earth salts (Pr(OH)3, ErCl3 · 6H2O) with mandelic acid (α-hydroxy-phenyl acetic acid, C8H8O3) and their crystal structures were determined on the basis of X-ray data. In the crystal structure of Pr(Man)3(ManH) (1) (monoclinic, P21, a = 574.8(1), b = 3042.5(4), c = 908.4(1) pm, β = 92.09(2)°, Z = 2) the Pr(III) ions are surrounded by eight oxygen atoms in a distorted square antiprismatic fashion with distances Pr-O in the range 241 to 254 pm. These polyhedra are connected by coordinative bonds to chains paralleling the crystallographic [100] direction. In Er(Man)3(H2O)2 (2) (orthorhombic, P212121, a = 577.7(3), b = 1816.3(13), c = 2329.4(13) pm, Z = 4) the crystal structure contains isolated complexes with octa-coordinated erbium atoms chelated by three mandelate anions through one of their carboxylate oxygen atoms and the alcoholic hydroxyl group. Two water molecules complete the distorted square antiprismatic coordination sphere.
2-Azaanthraquinones: Building Blocks for New Ring-Fused Imidazoles and their Transformation into Benzo[f]isoindole-4,9-diones
Authors: Frank Birgit , Beckert Rainer , Rau Sven , Görls Helmar
Published: August 2018

The modification of 2-azaanthraquinones with selected C1 building blocks gives a series of new imidazo-fused derivatives. Employing 2,3-dichloro-5,6-dicyanopyrazine as cyclization partner a rearrangement to yield derivatives of benzo[f ]isoindole-4,9-dione takes place. The Sonogashira crosscoupling reaction of the aminalester derivative of the azaanthraquinone resulted in well soluble silyl substituted acetylenes as well as ethinyl aniline which allows further derivatization reactions.
Electroreduction of Organic Compounds, 35. Quantum Chemical Calculations of Reaction Pathways for the Cathodic Dehalogenation of Chlorodibenzofurans and Oligochlorobenzenes
Authors: Golinske Dirk , Voss Jürgen
Published: August 2018

Quantum chemical (DFT) calculations on the course of the electroreductive carboxylation of chloroarenes were performed. An explanation for the extraordinary behaviour of 2- chlorodibenzofuran (2) as compared with the corresponding 1-chloro, 3-chloro and 4-chloro derivatives was sought for and was found in the particular reaction coordinate of 2 and in the SOMO spin density distributions of the four isomers. In the same way, the regioselectivity in the formation of dicarboxylic acids from hexachloro- and 1,2,4,5-tetrachlorobenzene was investigated by DFT-MO calculations and was shown to be due to orbital effects besides steric hindrance.
High-Pressure Synthesis of a Gallium Oxonitride with a Spinel-Type Structure
Authors: Kinski Isabel , Miehe Gerhard , Heymann Gunter , Theissmann Ralf , Riedel Ralf , Huppertz Hubert
Published: August 2018

The new compound Ga2.81O3.57N0.43 was crystallized under high-pressure / high-temperature conditions in a spinel-type structure from a prestructured gallium oxonitride ceramic, which was obtained from the single-source molecular precursor [Ga(OtBu)2NMe2]2 by thermal treatment in an ammonia atmosphere. The optimized precursor-derived gallium oxonitride ceramic remains nanocrystalline up to 600 °C and can be transformed at 7 GPa and 1100 °C into the crystalline phase Ga2.81O3.57N0.43. The structure, homogeneity, and nitrogen to oxygen ratio were determined using TEM coupled with an electron energy loss spectrometer (EELS) and an energy dispersive X-ray (EDX) spectrometer. For phase analysis and structure confirmation, X-ray powder diffraction data were measured.
The Synthesis, Structural Characterization and Conformational Analysis of (1,3-Bis(2-methyl-4-diethylaminophenyl)imidazolidin- 2-ylidene)chloro(1,5-cyclooctadiene)rhodium(I)
Authors: Karabıyık Hasan , Kılınçarslan Rafet , Aygün Muhittin , Çetinkaya Bekir , Büyükgüngör Orhan
Published: August 2018

A four-coordinated Rh(I) complex with a new heterocyclic carbene ligand, functionalized by amino donor pendants, 4, was synthesized and characterized by elemental analyses, NMR and IR spectroscopy, and the molecular structure of the title compound has been determined by X-ray crystallography. Crystallographic data: monoclinic, P21/m, a = 7.9307(5), b = 25.0061(12), c = 8.0780(6) Å , β = 101.366(6)°, V = 1570.58(17) Å3, ρcalc = 1.3515(1) g cm−3, Z = 2. The experimentally obtained structural parameters for compound 4 compare reasonably well with those calculated at the semi-empirical ZINDO/1 level of theory carried out to elucidate conformational flexibility and steric hindrances.
The Stannide LiRh3Sn5 – Synthesis, Structure, and Chemical Bonding
Authors: Sreeraj Puravankara , Johrendt Dirk , Müller Helen , Hoffmann Rolf-Dieter , Wu Zhiyun , Pöttgen Rainer
Published: August 2018

The lithium rhodium stannide LiRh3Sn5 was synthesized from the elements in a sealed tantalum tube and investigated via X-ray powder and single crystal diffraction: Pbcm, a = 538.9(1), b = 976.6(3), c = 1278.5(3) pm, wR2 = 0.0383, 1454 F2 values, and 44 variables. Refinement of the occupancy parameters revealed a lithium content of 92(6)%. LiRh3Sn5 crystallizes with a new structure type. The structure is built up from a complex three-dimensional [Rh3Sn5] network, in which the lithium atoms fill channels in the b direction. The [Rh3Sn5] network is governed by Rh-Rh (274 - 295 pm), Rh-Sn (262 - 287 pm), and Sn-Sn (289 - 376 pm) interactions. The lithium atoms have CN 13 (4 Rh+9 Sn). Electronic band structure calculations and the COHP bond analysis reveal strong Rh−Sn bonds and also significant Rh−Rh bonding within the Rh3Sn5 network, which is additionally stabilized by weak but frequent Sn−Sn interactions.
Efficient and Rapid Regioselective Deprotection of Isopropylidene Ketals
Authors: Mahalingam Sakkarapalayam M. , Aidhen Indrapal Singh
Published: August 2018

A simple and efficient protocol is described for the regioselective hydrolysis of terminal isopropylidene ketal protection in carbohydrate derivatives 1a - 11a. It uses either CoCl2 · 2H2O in acetonitrile or InCl3 in methanol at temperatures ranging from 50 to 60 °C. The low cost of CoCl2·2H2O along with its requirement in catalytic quantities offers a great advantage for the multi-gram scale reaction.
Synthese und Ringumwandlungen von 1,2,5-Oxadiazinan-3,6-dionen / Synthesis and Ring Transformations of 1,2,5-Oxadiazinan-3,6-diones
Authors: Geffken Detlef , Zydowitz Hans von , Ploetz Alf
Published: August 2018

1,2,5-Oxadiazinan-3,6-diones (8), easily available by cyclic carbonylation of α-amino-carbohydroxamic acids 7 with 1,1’-carbonyldiimidazole, are reacted with hydrazine to give 3- aminohydantoins (10). Depending on the substituents R1/R’ 8 was found to undergo an imidazole catalyzed oxidoreduction to 4-imidazolidinones (11) or α-iminophenylacetamides (12).
Synthesis of Decaline Analogues of Isovelleral
Authors: Johansson M. , Aujard I. , Röme D. , Anke H. , Sterner O.
Published: August 2018

Decaline analogues of the bioactive fungal sesquiterpene (+)-isovelleral (1a), retaining the bicyclo[4,1,0]hept-2-en-1,2-dicarbaldehyde system, were prepared, and their cytotoxic and antimicrobial activities were compared with those of the natural product. While the two isomers (±)-2 and (±)-3 were as active as isovelleral (1a), the isomer (±)-4 was approximately 10 times less potent.
Rapid Evaluation of Suitable Substrates with High Affinity to Artificial Caffeine Receptors by MS Based Techniques
Authors: Mirk Daniela , Luftmann Heinrich , Waldvogel Siegfried R.
Published: August 2018

A modification of our triphenylene ketal based receptor facilitates electrospray tandem mass spectrometry investigations. Binding affinities of eleven potential substrates, e.g. caffeine and other xanthine alkaloids, are probed in the gas phase with collision induced dissociation. The relative stabilities of the substrate-receptor complexes are rapidly determined and the findings are correlated with the corresponding results in solution.
Formation of meso-1,2-Bis(dimethylamino)-1,2-diphenylethane by Oxidative C-C Coupling Reaction
Authors: Fleischer Holger , Schollmeyer Dieter
Published: August 2018

The title compound was obtained from the reaction of N,N-dimethylbenzylamine with n-butyl lithium and sulfur in tetrahydrofuran at room temperature. Its molecular structure was investigated by means of single crystal X-ray diffraction and quantum chemical DFT methods. The formation of meso-1,2-bis(dimethylamino)-1,2-diphenylethane is likely to be due to an unusual α-deprotonation of N,N-dimethylbenzylamine, instead of the well known ortho-lithiation, with a subsequent oxidative C-C coupling of the anions. Ab initio calculations of the corresponding α- and o-deprotonated anions of N,N-dimethylbenzylamine showed the former to be more stable than the latter, due to delocalisation of the negative charge over the π-system of the phenyl ring. The choice of solvent and temperature is seen as the main reason for the unusual course of the reaction.
Acyclische und cyclische Silylazine und Azinylsilane / Acyclic and Cyclic Silyalzines and Azinylsilanes
Authors: Armbruster N. , Klingebiel U. , Noltemeyer M.
Published: August 2018

C-lithiated bis(tert-butyl-methyl)ketazine reacts with halosilanes to give the monosilylketazines, t-Bu(Me)C=N-N=C(t-Bu)-CH2R, (1 - 7). (1: R = SiMe3; 2: R = SiClMe2; 3: R = SiClMePh; 4: R = Cl2SiPh; 5: R = SiCl3; 6: R = SiMe2Ph; 7: R = F2SiN(t-Bu)SiMe3). The bis(ketazinyl)silanes [t-Bu(RCH2) C = N-N = CCH2-t-Bu]2 SiMe2 8, 9 are formed in the reaction of the same lithiated ketazine or 1 with Cl2SiMe2 in a molar ratio of 2 : 1, (8: R = H; 9: R = SiMe3). Di(silyl)ketazines (10, 11) are obtained from lithiated 1 and ClSiMe2Ph in a molar ratio of 1:1 and from dilithiated ketazine with F2Si(i-Pr)2 in a molar ratio of 1 : 2 [t-Bu(RH2C)C=N-N=C(CH2R’)t-Bu, 10: R = SiMe3, R’ = SiMe2Ph; 11: R,R’ = FSi(i-Pr)2]. The tris(ketazinyl)fluorosilane 12 is isolated from the reaction of SiF4 with the lithiated ketazine. 2-Alkenyl-1,2-diaza-3-sila-5-cyclopentenes, t-Bu(CH2)C- [N-SiR,R’-CH2-C(t-Bu)=N], (14 - 17) are obtained from the dilithiated ketazine and Hal2SiRR’. (14: Hal = Cl, R = Me, R’ = Ph; 15: Hal = F,R = t-Bu, R’ = Ph; 16: Hal = F,R = t-Bu, R’ = F; 17: Hal = F, R = N(t-Bu)SiMe3, R’ = F). X-ray structure analyses are presented for 7, 11, and 17.
9-Oxabicyclo[3.3.1]nona-2, 6-diene. Short Access and Allylic Bromination
Authors: Bassioni Ghada , Delgado Fernando S. , Jaeggy Matthieu , Köhler Frank H. , Nogai Stefan , Ruiz-Pérez Catalina
Published: August 2018

9-Oxabicyclo[3.3.1]nona-2, 6-diene (3) has been synthesized from cycloocta-1, 5-diene in two steps in an overall yield of 88%. The dihedral-angle dependence of its 1H solution NMR data and the double signal set of its 13C CP MAS NMR spectrum correspond to the results of the single crystal structure analysis. Reaction of 3 with N-bromosuccinimide in the presence of sodium peroxodisulfate or benzoylperoxide has led in good yield to a dibromo derivative 4, and a tribromo derivative 5, respectively. Compounds 4 and 5 feature two allylic bromine substituents, while an additional vinylic bromine atom is present in 5. According to a single crystal structure study the lattice of 4 consists of pairs of enantiomers similar to those found in the case of 3.
Thin-Layer Densitometry as an Alternative Tool in the Quantitative Evaluation of the Free Radical Scavenging Activity of Natural Antioxidants
Authors: Abourashed Ehab A.
Published: August 2018

An HPTLC system commonly used for chromatographic separations and analytical quality control has been utilized non-chromatographically as a screening tool for antioxidant activity in the 2,2- diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging assay. The accurate and precise capabilities for sample application and densitometric analysis of dry spots were applied to determine the 50% inhibition of DPPH (IC50) by a number of natural antioxidants at 530 nm. Concentration-response curves were generated from 3rd degree polynomial fitting of data acquired for each antioxidant at 4 concentration levels. The IC50 values ranged from 9.0 - 332.8 μM with quercetin being the most active and silybin the least active of the pure compounds. Three antioxidant extracts were also evaluated and grapeseed extract was the most active (IC50 8.3 μg/ml). The coefficients of variation for all IC50 values were around 5% which indicated method reproducibility and the suitability of the used system for the intended purpose. Based on its densitometric evaluation of dry spots, the described technique provides an alternative to the spectrophotometric evaluation of samples in solution.
DNA Binding of Iron(II)-Phenanthroline Complexes: Effect of Methyl Substitution on Thermodynamic Parameters
Authors: Mudasira  , Yoshiokab Naoki , Inoueb Hidenari
Published: August 2018

The influence of methyl substitution on the thermodynamic parameters for the binding of [Fe(DMP)3]2+ and [Fe(TMP)3]2+ (DMP = 4,7-dimethyl-1,10-phenanthroline, TMP = 3,4,7,8-tetramethyl- 1,10-phenanthroline) to calf thymus DNA (ct-DNA) has been studied by determining their equilibrium binding constants (Kb) at various salt concentrations and temperatures. Kb of the iron(II) complexes to ct-DNA decreases with the salt concentration in the solution, suggesting considerable electrostatic interaction in the ct-DNA binding of the iron(II) complexes. In contrast, Kb of the DNA binding increases with temperature, indicating that the DNA binding reaction of the complex is endothermic and entropically driven. The evaluation of the non-electrostatic binding constant (K0
t) based on polyelectrolyte theory has revealed that the K0
t portions of the total binding constant (Kb) are relatively large and reach 46.4% for [Fe(DMP)3]2+ at [Na+] = 0.075 M and 43.9% for [Fe(TMP)3]2+ at [Na+] = 0.100 M. The contribution of non-electrostatic binding free energy (ΔG0
t ) to total binding free energy change (ΔG0) is extremely large, i. e. > 90% for both iron(II) complexes at [Na+] = 0.05 M, suggesting that the stabilization of the DNA binding is mainly contributed from the non-electrostatic process. The effect of methyl substitution on electrostatic (ΔG0
pe) and non-electrostatic (ΔG0
t ) binding free energy changes has been systematically evaluated using the quantity of ΔΔG0
pe and ΔΔG0
t relative to that of the parent iron(II) complex, [Fe(phen)3]2+. The results indicate that the substitution of hydrogen atoms in the phen ligand by methyl groups decreases slightly the electrostatic binding free energy changes, but tremendously increases the non-electrostatic ones to yield net binding free energy changes which are more favorable for the ct-DNA binding.
The Periodic Electronegativity Table
Authors: Boeyens Jan C.A.
Published: August 2018

The origins and development of the electronegativity concept as an empirical construct are briefly examined, emphasizing the confusion that exists over the appropriate units in which to express this quantity. It is shown how to relate the most reliable of the empirical scales to the theoretical definition of electronegativity in terms of the quantum potential and ionization radius of the atomic valence state. The theory reflects not only the periodicity of the empirical scales, but also accounts for the related thermochemical data and serves as a basis for the calculation of interatomic interaction within molecules. The intuitive theory that relates electronegativity to the average of ionization energy and electron affinity is elucidated for the first time and used to estimate the electron affinities of those elements for which no experimental measurement is possible
Rapid and Facile Synthesis of 4-Aryl-5-imino-3-phenyl-1H-naphtho[2,3-f]-1,2,4-triazepine-6,11-diones via the Reaction of Amidrazones with Dicyanonaphthoquinone
Authors: Aly Ashraf A. , NourEl-Din Ahmed M. , Gomaa Mohsen A.-M. , Fahmi Magda S.
Published: August 2018

One-pot syntheses of various 4-aryl-5-imino-3-phenyl-1H-naphtho[2,3- f ]-1,2,4-triazepine-6,11- diones 5a - f via reaction of amidrazones 1a - f with 1,4-dioxo-1,4-dihydronaphthalene-2,3- dicarbonitrile (4) are reported
Crystal Structure and Magnetic Properties of the Compounds Yb(Zn,Al)~6 and YbZn~6
Authors: Fornasini Maria L. , Manfrinetti Pietro , Mazzone Donata , Dhar Sudesh K.
Published: August 2018

The title compounds were synthesized and their crystal structures determined by single crystal X-ray diffraction data. Both compounds crystallize with the cubic space group Im3̄̅. Yb(Zn,Al)∽6: a = 14.299(4) Å , wR(F2) = 0.041, with Yb25.39(2)Zn138.2(3)Al7.7(3) as the refined composition; YbZn∽6: a = 14.298(4) Å , wR(F2) = 0.079, with Yb25.05(3)Zn146.83(9) as the refined composition. Their crystal structures are closely related to the YCd6 type, with two different details: Zn/Al (or Zn) atoms in the 8c sites center the cubic interstices of the structure; the pentagonal dodecahedron cavities are partially filled by ytterbium atoms in the 2a sites, with an environment topologically similar to that found in the clathrate-I compounds. Magnetic properties of the two compounds are also reported.
Crystal Structures and Thermal Behavior of Alkaline Earth Tricyanomethanides
Authors: Bessler Karl E. , Gatto Claudia C. , Romualdo Lincoln L. , Ellena Javier A. , A. Sales Maria J. de
Published: August 2018

The alkaline earth tricyanomethanides Mg(tcm)2 · 2H2O, Ca(tcm)2, Sr(tcm)2 ・H2O and Ba(tcm)2 · 2H2O were prepared from aqueous solutions of the respective chlorides and silver tricyanomethanide. Their IR spectra and thermal behavior are described. The crystal structures of Ca(tcm)2 and Ba(tcm)2 · 2H2O were determined by single crystal X-ray diffraction. The structure of Ca(tcm)2 is of the type found for several transition metal tricyanomethanides [1], containing two independent interpenetrating networks. Ba(tcm)2 · 2H2O has a unique crystal structure corresponding to a three-dimensional coordination polymer with nine fold coordinated Ba atoms connected by water molecules and tricyanomethanide anions.
Fischer-Tropsch CO-Hydrogenation on SiO2-supported Osmium Complexes
Authors: Bungane Ntombovuyo , Welker Cathrin , Steen Eric van , Claeys Michael
Published: August 2018

The conversion of carbon monoxide with hydrogen was studied on a standard Os on SiO2 catalyst at different reaction temperatures, in the range between 200 and 300 °C. Additionally, supported di- and triatomic organometallic Os complexes were tested for their activity in the Fischer-Tropsch synthesis at 220 °C. All compounds showed formation of hydrocarbons, indicating that the organoosmium complexes are indeed active for C─C bond formation. Osmium as Fischer-Tropsch catalyst, however, is approximately 100 times less active compared to ruthenium. Very high methane selectivities (> 90 C-%) were obtained as well as high olefin to paraffin ratios, in particular with the organometallic complexes tested.
Microwave-assisted N-Arylation of Indoles via C(sp2)–N(sp2) Bond Formation by Aromatic Nucleophilic Substitution Reactions
Authors: Xu Hui , Fan Ling-Ling
Published: August 2018

Microwave-assisted nucleophilic aromatic substitution on aryl halides with different indoles is described. Moderate to good yields are obtained in short reaction time (25 - 40 min) when coupling indoles with fluoro- and chloro-substituted aryl halides under catalyst-free conditions.
One-pot Synthesis of 1,6-Naphthyridines, Pyranopyridines and Thiopyranopyridines
Authors: Abdel-Wadood Fatma K. , Abdel-Monem Maisa I. , Fahmy Atiat M. , Geies Ahmed A.
Published: August 2018

A one-step synthesis of [1,6]naphthyridine-2(1H)-thione (3a), pyrano[3,4-b]pyridine-2(1H)- thione (3b), thiopyrano[3,4-b]pyridine-2(1H)-thione (3c) and 6-oxoquinoline-2(1H)-thione (3d) through the reaction of benzylidene-cyanothioacetamide (1) with cyclic ketones 2a−d is described. The reaction of 3a−d with organyl chlorides yielded the 2-alkylthio-3-cyanopyridines 4a−p which upon refluxing in ethanolic sodium ethoxide afforded the thieno[2,3-b]pyridine derivatives 5a−n. Some of the synthesized compounds were screened for the activity against bacteria and fungi.
Synthesis of New Polysubstituted Pyrrolidinones with Potential Biological Activity
Authors: Burdzhiev Nikola T. , Stanoeva Elena R.
Published: August 2018

The reaction of succinic anhydride and N-benzylidene-benzylamine gave rise to the corresponding substituted trans-5-oxopyrrolidine-3-carboxylic acid, which was transformed stereoselectively into two series of compounds. The first one consists of carboxamides, and the second one includes aminomethyl derivatives. The compounds prepared incorporate both a pyrrolidinone part and other nitrogen containing heterocyclic fragments of pharmacological interest.
Synthesis, Structure and Magnetic Characterization of a New Phosphate K1.84Fe1.42Nb0.58(PO4)3 with the Langbeinite- type Structure
Authors: Babaryk Artem A. , Zatovsky Igor V. , Slobodyanik Nikolay S. , Ogorodnyk Ivan V.
Published: August 2018

A new complex phosphate K1.84Fe1.42Nb0.58(PO4)3 has been synthesized by the self-flux technique. The X-ray single crystal structure and magnetic properties were studied. The compound crystallizes in the cubic system with space group P213 (a = 9.9404(10) Å ) and belongs to the langbeinite structure type. The structure contains [M2P3O18] building units. “Closed” fragments [M8P9O60] provide space for location of two potassium atoms. Antiferromagnetic interactions were detected at low temperatures which originate from superexchange through a M(1)-O-P-O-M(2) pathway with corresponding J = −5.5(1) cm−1. The relationship between the UV/vis absorption and the structure is discussed.
Introduction of Perfluoroalkyl Substituents into Heteroarenes via Nucleophilic Substitution of Hydrogen
Authors: Mąkosza Mieczysław , Loska Rafał
Published: August 2018

A summary of research in the area of fluoroalkylation of electron-deficient aromatic compounds is presented. The reaction of dinitro- and cyanonitroarenes with trifluoromethyl-trimethylsilane (Me3SiCF3) and tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF) and subsequently with DMD provides trifluoromethylated cyano- and nitrophenols via oxidative nucleophilic substitution of hydrogen. Addition of fluorinated carbanions, generated either by addition of F− anions to hexafluoropropene or by activation of Me3SiCF3, to N-alkylazinium salts leads to dihydropyridines, dihydroquinolines etc., oxidation of which affords the respective fluoroalkylated heterocycles.

1,3-Dipolar cycloaddition of azine N-oxides to hexafluoropropene gives 2-heteroaryl-2,3,3,3-tetrafluoropropionic acid fluorides, which react with various protic nucleophiles to give esters and amides of 2-heteroarylperfluoropropionic acids, whereas reaction with water and decarboxylation of the free acids gives azines with a 1,2,2,2-tetrafluoroethyl group at C-2.
Thia- and Selena-Heterocycles Containing Cycloamidine Substructures: Ring Contraction Reactions of 1,3,4-Thia-/Selenadiazines
Authors: Fleischhauer Jan , Beckert Rainer , Hornig David , Günther Wolfgang , Görls Helmar , Klimesova Vera
Published: August 2018

1,3,4-Thia/selena-diazines proved to be suitable starting materials for ring contraction reactions. Treatment with acetic acid/water mixtures leads to highly substituted 1,3,4-thia/selenadiazoles. In addition, the selenadiazoles formed undergo a fast Dimroth-rearrangement to finally yield derivatives of 1,2,4-triazole. The structures of all new derivatives were confirmed by NMR experiments, mass spectroscopy, elemental analysis and X-ray structural analysis.
New Approaches to Branched β-Amino α-Hydroxy Acids, Taxol Side-chain Analogs
Authors: Li Feng , Li Zhao-Ming , Yang Hua , Jäger Volker
Published: August 2018

The phenylisothreonine derivatives, taxol side-chain analogs, were synthesized by two routes, one based on the highly stereoselective addition of a phenyl Grignard reagent to the L-threose-derived nitrone 7, and the other using asymmetric α-alkoxyallylation of the ketimine 20 with chiral allyl boron reagents.
Blue Fluorescence of a Binuclear Cd(II) Complex: [Cd(ClC2H4CO2)2(phen)]2
Authors: Peng Zhen-Shan , Jiang Yao-Hui , Jiang Wen-Jun , Deng Qian , Liu Jian-Xiang , Cai Tie-Jun , Huang Ming-Zhong
Published: August 2018

A new binuclear complex, [Cd(ClCH2CH2CO2)2(phen)]2 (1), has been synthesized and structurally characterized by single crystal X-ray diffraction methods. The Cd atoms are linked by carboxylate oxygen atoms into a four-membered Cd2O2 rhombic ring with a Cd···Cd separation of 3.824 Å . Two carboxylate groups act as bidentate, and two as both bidentate bridging and bidentate chelating ligands. The hydrogen bonding and π-π stacking interactions are responsible for the supramolecular assembly and stabilization of the crystal structure. The complex has been characterized by elemental analysis, IR and UV/Vis spectra, and thermogravimetric and differential thermal analysis (TG/DTA). The complex exhibits blue fluorescence in the solid at room temperature.
Synthesis and Structure of and Cation Distribution in the Zirconium Cluster Rb[(Zr6C)Cl15]
Authors: Rohm Henning W. , Köckerling Martin
Published: August 2018

Rb[(Zr6C)Cl15] was prepared by heating ZrCl4, Zr powder, RbCl and Al4C3 at 850 °C for 21 days. The crystal structure was determined by single crystal X-ray diffraction (space group Pmma, a = 18.484(3), b = 18.962(2), c = 9.708(1) Å, V = 2505.4(6) Å3, and Z = 4). Rb[(Zr6C)Cl15] crystallises in the Cs[Nb6Cl15]-type structure. It is built up from two interconnected types of cluster chains, one with linear Zr−Cla−a-Zr bridges, the other one with bent bridges. The rubidium cations are spread over three different sites within the cluster network which differs significantly from the cation distribution in the comparable potassium and caesium phases. The cation distribution can be rationalised considering the size of the cavities and the Coulombic interactions.
Reaction of Hexagonal Boron Nitride Nano-crystals under Mild Hydrothermal Conditions
Authors: Zhu Lingling , Lian Gang , Tan Miao , Wang Qilong , Zhao Xian , Cui Deliang , Tao Xutang
Published: August 2018

The reaction between hexagonal boron nitride (hBN) nano-crystals and water at low temperature and low pressure has been investigated. The results reveal that this reaction can be greatly promoted by increasing the hot-pressing temperature. However, when the temperature is above 280 °C, the reaction is too fast to be controlled by varying the hot-pressing pressure and time. On the other hand, stress and defects are induced in hBN nano-crystals by the hydrothermal hot-pressing process, resulting in a shift of the IR absorption bands and a deterioration of crystalline perfection. These results may be useful for synthesizing cBN by the hydrothermal method and converting hBN nanocrystals into cBN under moderate conditions.
Using Mild High-pressure Shock to Generate Bacterial Ghosts of Escherichia coli
Authors: Vanlint Dietrich , Tesfazgi Mebhratu Mehari , Michiels Chris W. , Aertsen Abram
Published: August 2018

In the context of vaccine development, bacterial ghosts are inert cells that retain the capacity to activate the immune system, and that can be used as vaccine or carrier for subunit or DNA vaccines. In this study we provide evidence that increasing the copynumber of the E. coli K12 mrr locus can render naturally occurring and virulent avian pathogenic E. coli (APEC) strains hypersensitive to high pressure. We further demonstrate that mild HP shock generates inactive bacterial ghosts from these cells that have not incurred any microscopically visible structural damage. Possible benefits of high-pressure generated bacterial ghosts as a vaccine are discussed.
Characterisation of a Piezotolerant Mutant of Lactobacillus sanfranciscensis
Authors: Pavlovic Melanie , Hörmann Sebastian , Vogel Rudi F. , Ehrmann Matthias A.
Published: August 2018

Incubation under sublethal high pressure (50 MPa) allowed the isolation of a piezotolerant mutant of Lactobacillus sanfranciscensis. Compared to the wild type this strain showed faster growth at 50 MPa and an altered temperature-dependent growth at ambient pressure. Additionally, an altered antibiotic resistance pattern was detected. To address the molecular basis of the mutation the genotypic characterisation was focused on alterations of ribosomal components. Northern analysis using ssrA (transfer mRNA) as probe revealed a constitutive overexpression in the mutant. A 2.2 fold induction after pressure shock and increased pressure sensitivity of a ssrA-insertional mutant of L. sanfranciscensis indicate the tmRNA as genetic determinant of a piezotolerance response in the wild type. Thus, we propose trans-translation and peptide tagging, processes that promote recycling of stalled ribosomes and prevent accumulation of abortively synthesised polypeptides to be involved in combating high-pressure damage and conferring moderate piezotolerance.
Neue gemischte Sr/Ba-Trielide AIIInxMIII
1– x (M = Ga, Al)
Authors: Wendorff Marco , Röhr Caroline
Published: August 2018

A series of new ternary mixed Sr and Ba trielides of overall composition 1 : 1 was synthesized from stoichiometric quantities of the elements. The structures of the new compounds were determined using single crystal X-ray data. In the case of the Sr compounds, commensurately modulated new superstructures of the CrB type are formed in the In-rich part of the ternary system SrAl - SrGa - SrIn: The gallides, SrIn1−xGax (x = 0.30, orthorhombic, space group Ima2, a = 1954.2(7), b = 1305.6(4), c = 1272.6(3) pm, Z = 48, R1 = 0.0848) are formed in the composition range x = 0.20 to 0.30. The closely related aluminide SrIn1−xAlx (x = 0.04, orthorhombic, space group Pnna, a = 1280.1(7), b = 1482.0(5), c = 1308.7(5) pm, Z = 36, R1 = 0.1164) and the isotypic Zn compound SrIn0.90Zn0.10 (a = 1277.7(4), b = 1489.9(3), c = 1301.3(4) pm, R1 = 0.0629) also contain mainly In as the triele element. The structures, similar to CrB, contain zig-zag chains of two-bonded In-Ga/Al, in which the ordering of the trieles results in a strong wavelike form of the originally planar zig-zag chains. In contrast, no corresponding Ba compounds were formed. Instead, BaIn0.46Ga0.54 (triclinic, space group P1̄, a = 661.1(3), b = 679.4(2), c = 712.4(3) pm, α = 69.13(3), β = 77.14(3), γ = 84.27(3)°, Z = 2, R1 = 0.0557) crystallizes with a new structure type and exhibits a planar rhomb-like anion with both two- and three-bonded In/Ga atoms. Attempts to obtain 1 : 1 compounds in-between BaAl and BaIn resulted in the formation of the 5 : 6 phases Ba5In6−xAlx (x = 4.1/5.1, hexagonal, space group P6̄m2, a = 612.2(4)/608.6(1), c = 1124.6(10)/1116.80(6) pm, Z = 1, R1 = 0.0608/0.0147) which are isotypic to Ba5M5
IIIMIV (MIII = Al, Ge; MIV = Sn, Pb). Their structures contain isolated In anions (coordinated by 11 Ba atoms) and sheets of 3- and 4-bonded Al/In atoms similar to those known from the structures of Ba aluminides like Ba3Al5.
Isolation and Synthesis of Methyl Bovinate, an Unusual Pulvinic Acid Derivative from Suillus bovinus (Basidiomycetes)
Authors: Besl Helmut , Bresinsky Andreas , Kilpert Claus , Marschner Wolfgang , Schmidt Helga M. , Steglich Wolfgang
Published: August 2018

Cultures and fruit bodies of Suillus bovinus produce the pulvinic acid derivative methyl bovinate (4), which contains an extra carbonyl group that bridges ring A of methyl variegatate with the hydroxy group at the central butenolide ring. This unprecedented structure was deduced fromthe spectroscopic data and confirmed by total synthesis via a grevillin intermediate. In this synthesis, the menthyl group was used for carboxyl protection.
Synthesis and Luminescence of RhIII(phpy)2(E∪O) Complexes with phpyH = 2-Phenylpyridine and E∪OH = Tropolone, Flavonol and Lumichrome
Authors: Kunkely Horst , Pawlowski Valeri , Vogler Arnd
Published: August 2018

The complexes RhIII(phpy)2(E∪O) with phpy− = deprotonated 2-phenylpyridine and E∪O− = bidentate anions of the biologically important compounds E∪O (troH = tropolone, flaH = flavonol and lumH = lumichrome) have been prepared and characterized with regard to their optical properties. The RhIII(phpy)2 fragment is a useful probe for the emission behavior of these complexes since the phpy IL triplet can serve as a marker. Only the IL states of tp− and lum− are located below the phpy IL states. While RhIII(phpy)2(fla) is quite remarkable because it shows an IL (fla) fluorescence, RhIII(phpy)2(lum) displays an IL (lum) phosphorescence as expected owing to the heavy-atom effect.
TiO2 Nanoparticles Functionalized by a Temperature-sensitive Poly(N-isopropylacrylamide) (PNIPAM): Synthesis and Characterization
Authors: Zhang Linna , Zhang Shengmao , He Benfang , Wu Zhishen , Zhang Zhijun
Published: August 2018

TiO2 nanoparticles functionalized by poly(N-isopropylacrylamide), PNIPAM in short, were prepared via seeded emulsion polymerization of N-isopropylacrylamide (NIPAM) in the presence of N,N´-methylene-bis(acrylamide) (MBAA) as the crosslinking monomer. The morphology and structure of the TiO2/PNIPAM hybrid hydrogel were characterized by means of transmission electron microscopy, X-ray powder diffraction, and FT infrared spectroscopy. The response of the composite to temperature variations was also investigated. The results indicate that the title inorganic/organic hybrid has a sphere-like shape and is composed of inorganic TiO2 nanoparticles and a biocompatible polymer matrix, showing excellent thermosensitivity, as evident from relevant optical photographs at different temperatures. The thermosensitive TiO2 nanoparticles doped in PNIPAM matrix may have potential application in the remediation of wastewater streams.
Synthesis and Crystal Structure of Triethylammonium 5-[(2,2-Dimethyl- 4,6-dioxo-1,3-dioxan-5-ylidene)(methylthio) methyl]-1,3-dimethylpyrimidine- 2,4,6-trionate
Authors: Al-Sheikh Ahmad , Sweidan Kamal , Sweileh Bassam , Steimann Manfred , Schubert Hartmut , Kuhn Norbert
Published: August 2018

Triethylammonium 5-[(2,2-dimethyl-4,6-dioxo-1,3-dioxan- 5-ylidene)(methylthio)methyl]-1,3-dimethylpyrimidine- 2,4,6-trionate (6) is obtained as red-orange stable crystals by reaction of 5-[bis(methylthio)methylene]-2,2-dimethyl- 1,3-dioxane-4,6-dione (5) with 1,3-dimethylbarbituric acid (2) in the presence of triethylamine in excellent yield. The crystal structure of 6 confirms the negative charge to be localized at the barbituric-acid ring in its enolate form.
First Trichloroaluminum Adducts of Silyliminoborenes
Authors: Ott Holger , Matthes Christoph , Schmatz Stefan , Klingebiel Uwe , Stalke Dietmar
Published: August 2018

The reactions between the fluoroboranes [(Me3Si)2N]2BF or (Me3Si)2N-BF-N(CMe3)SiMe3 and AlCl3 in diethyl ether afforded the first tri- and disilylated aminoiminoborenes, which were isolated and structurally confirmed as AlCl3 adducts, Me3Si(AlCl3)N=B=N(R)SiMe3, [R = SiMe3 (1), CMe3 (2)]. Density functional theory calculations of 1 and 2 were performed to understand the regioselectivity of the adduct formation.
The Effect of Mechanical Activation on the Synthesis of MgFe2O4 from Mixtures of MgCO3· Mg(OH)2 · xH2O and FeC2O4 ·2H2O
Authors: Berbenni Vittorio , Marini Amedeo , Milanese Chiara , Bruni Giovanna
Published: August 2018

The synthesis of MgFe2O4 has been attempted starting from mixtures of 4MgCO3 ·Mg(OH)2 · xH2O and FeC2O4 · 2H2O by combining mechanical activtion of the mixtures (by high-energy milling) with annealing at temperatures between 673 and 1073 K. TG measurements of mixtures of the precursors have been performed to assess the reaction mechanism, and to determine the minimum temperature where the two binary oxides (MgO and Fe2O3) are formed. X-Ray powder patterns of the milled / annealed mixtures have shown that MgFe2O4 is formed in an amorphous state already upon thermal treatment at 673 K, while annealing of the mixtures (not mechanically activated) at temperatures as high as 1473 K of the mixtures does not lead to the complete formation of MgFe2O4. The molar specific heat and the Curie temperature of the milled / annealed mixtures have been determined by DSC: MgFe2O4 is obtained provided that the annealing of the milled mixture is performed at temperatures as low as 873 K. The effect of the annealing temperature on the surface area of MgFe2O4 has been determined by BET measurements.
Metal-assisted Oxidative Cyclization of Arylamidrazones II [1]. Novel Synthesis of 1,4-Diaryl[1,2,4]triazino[6,5-h]quinolines
Authors: Khanfar Monther A. , Thaher Bassam A. Abu , Zahra Jalal A. , Al-Qawasmeh Raed A. , El-Abadelah Mustafa M. , Voelter Wolfgang
Published: August 2018

New model 1,2,4-triazino[6,5-h]quinolines 8a - c are prepared by oxidative cyclization of the respective N-(quinolin-8-yl)amidrazone precursors 7a - c using copper(II) chloride. Interestingly, the cyclized products 8a - c were found to be arylated at N1 position. Analytical and spectral (MS, NMR) data of the title products are in compliance with the allocated structures.
The Channel Structure of Mn0.86In0.12Ga2S4
Authors: Haeuseler Hartmut , Wagener Michael , Zhang Junyu
Published: August 2018

By solid state reaction of the binary sulfides, a new compound, Mn0.86In0.12Ga2S4, has been synthesized and its crystal structure determined. The compound crystallizes in the space group C2/m (no. 12) with a = 1232.6(2), b = 2636.9(5), c = 642.4(1) pm, β = 100.66(3)°, Z = 14. In the structure empty channels with a cross section of 320× 1082 pm2 running parallel to [001] are present.