bluuebunny/crossref_metadata_2025_split huggingface dataset:
An ab initio Hartree-Fock Investigation of Endohedral Sc@C82
Authors: Gruß Andrea , Böhm Michael C. , Schulte Joachim , Dinse Klaus-Peter 
Published: February 2015

Abstract
The electronic structure of endohedral Sc@C82 with a C82 cage of C2v symmetry has been studied by ab initio Hartree-Fock (HF) calculations. The optimized position of Sc in the configuration of minimum energy is predicted to be on the two-fold axis of the fullerene cage. In the corresponding configuration Sc is above the center of a hexagon of site symmetry C2 . This structure of C2v symmetry is nearly degenerate with Cs and Ct structures with Sc slightly displaced from the center of the coordinated hexagon. The binding energy of the endohedral complex is larger than 3.55 eV. The ab initio HF data of the C2v topoisomer of the fullerene unit are compared with new experimental findings and HF results derived for the 3(C2) topoisomer of the C82 cage.
Optisch aktive Übergangsmetall-Komplexe, 122. Synthese von Palladium(II)-Schiff-Base-Komplexen -intramolekulare Wechselwirkungen / Optically Active Transition Metal Complexes, 122. Synthesis of Palladium (II) Complexes with Schiff Base Ligands -Intramolecular Interactions
Authors: Brunner Henri , Niemetz Markus , Zabel Manfred 
Published: February 2015

Abstract
Imines of salicylaldehyde and 2,6-diformyl-p-cresol have been used as ligands in palladium (II) complexes. Enantiomerically pure ligands give enantiomerically pure complexes, racemic ligands give racemates and meso-forms. Differences between the respective isomers of the ligands within the complexes and between the diastereomers of the complexes were investigated. Crystal structure analyses established the trans configuration at the metal center.
Bis(diphenylphosphanyl)amine and its Disulfide and Diselenide. Application of the INEPT-HEED Pulse Sequence for Measurement of 1J(31P, 15N) and Isotope Induced Chemical Shifts 1⊿ 14/15N(31P) at Natural Abundance of 15N
Authors: Wrackmeyer Bernd , Garcia-Baez Efren , Zuno-Cruz Franciso J. , Sanchez-Cabrera Gloria , Rosales Maria J. 
Published: February 2015

Abstract
Bis(diphenylphosphanyl)amine (1), the disulfide 1S and diselenide 1Se were selected to show the efficient application of the INEPT-HEED pulse sequence for measuring coupling constants 1J(31P.15N) and isotope induced chemical shifts1⊿14/15N(31P), both at natural abundance of 15N, from 31P NMR spectra. The sign of 1J(31P,15N) (> 0) in all three compounds was determined by selective heteronuclear ]1H{31P} double resonance experiments.
Enaminouraciles as Precursors for Synthesis of Pyrimido[4,5-a]pyrimidine- 2,4-diones
Authors: Hamama W. S. 
Published: February 2015

The reaction of 6-aminouracil 1 with formaldehyde and secondary amines in ethanol at room temperature gave the corresponding 5-alkylaminomethyl derivatives (2a-c) and bis(4- pyrimidyl) methane (4). Also, Mannich reaction with primary aliphatic and aromatic amines at room temperature afforded pyrimid[4,5-d]pyrimidine (5 and 6).
Treatment of 1 with o-phenylenediamine through transamination gave com pound 7 which cyclized through intramolecular Mannich reaction with formalin to yield pyrimido[4,5-e]-[l,4]diazepine (8).
Darstellung und magnetische Eigenschaften einiger kristalliner Nitroxidradikale/Synthesis and Magnetic Properties of Some Crystalline Nitroxide Radicals
Authors: Griesar K. , Soto-Bustamante E. A. , Haase W. 
Published: February 2015

Abstract
The syntheses of different nitroxide radicals are reported. The thermal behaviour of the ni­ troxide radicals was examined by polarizing microscopy, differential scanning calorimetry as well as X-ray diffraction experiments. Temperature dependent magnetic susceptibility mea­surements were carried out in order to determine the magnetic properties of these nitroxide radicals. The majority of the radicals presented here show weak antiferromagnetic exchange interactions.
Application of High-Resolution-Magic-Angle-Spinning (HR-MAS) NMR Spectroscopy to Cosmetic Emulsions
Authors: Tseng Li-Hong , Emeis Detlef , Raitza Martin , Händel Heidrun , Albert Klaus 
Published: February 2015

Abstract
HR-MAS NMR spectroscopy was utilized for the characterization of three cosmetic emul­sions. The emulsions had the same chemical composition and were prepared in the same way except the homogenization step. Magic angle spinning (M A S) of the emulsions was applied to improve signal resolution by eliminating susceptibility changes as well as residual dipolar interactions within the sample. Spin-lattice relaxation times (T1) were determined according to the inversion recovery technique in the temperature range of -10 °C to 40 °C to find out phase changes of the sample ingredients. 1H and 13C NMR signals of the individual components were assigned by use of different 1D and 2D NMR experiments. The HR-MAS NMR technique offers many possibilities to further investigate samples between the liquid and the solid state.
Production of 5,7-Dihydroxy-6-hydroxymethyl-2-methoxy-1,4-naphthoquinone by the Cultured Lichen Mycobiont of Opegrapha sp. No. 9771836
Authors: Amano Takuo , Miyagawa Hisashi , Ueno Tamio , Hamada Nobuo 
Published: February 2015

Abstract
A new pigment was isolated from an osmotically-stressed culture of the lichen mycobiont of Opegrapha sp. and the structure was determined to be 5, 7-dihydroxy-6-hydroxymethyl-2-methoxy-1, 4-naphthoquinone by spectroscopic analyses.
Übergangsmetallkomplexe mit Schwefelliganden, 145 [1]. [Ru(NO)('pybuS4')]Br, ein Komplex mit [Ru(NO)(NS4)]-Gerüst, aktivierten CH2-Gruppen und interionischen Wechselwirkungen im Festkörper ['pybuS4'2- = 2,6-Bis(2-mercapto-3,5-di-terM>utylphenylthio) dimethylpyridin(2-)] / Transition Metal Complexes with Sulfur Ligands, 145 [1]. [Ru(NO)('pybuS4 ')]Br, a Complex with [Ru(NO)(NS4)] Core, Activated CH2 Groups, and Interionic Interactions in the Solid State ('pybuS4'2- = 2,6-Bis(2-mercapto-3,5-di-terf-butylphenylthio)dimethylpyridine(2-))
Authors: Sellmann Dieter , Häußinger Daniel , Gottschalk-Gaudig Torsten , Heinemann Frank W. 
Published: February 2015

Abstract
In the search for soluble and reactive ruthenium nitrosyl complexes, [Ru(NO)('pybuS4')]Br ([2]Br) was synthesized by template alkylation of NBu4[Ru(NO)('buS2')2] with py(CH2,Br)2 ['pybuS4'2-= 2,6-bis(2-mercapto-3,5-di-tert-butyl-phenylthio)dimethylpyridine(2-); 'buS2'2- = 2-mercapto-3,5-di-tert-butylphenylthiolate(2-); py(CH2Br)2 = 2,6-bis(bromomethyl)pyridine]. The solid state structure of 2 has been determined by X-ray diffraction, which reveals a head-to-head O-O interaction between the linear Ru-NO entities. The ligand CH2 protons of [2]+ are activated and exchange with D+ under ambient conditions. The ν (NO) band of [2]Br appears at 1841 cm-1 in the solid state (KBr or hostaflon mull) and is significantly blue-shifted in solution (1879 cm-1 in MeOH, 1886 cm-1 in DMF). A similar blue-shift (1866 cm-1 in KBr vs. 1888 cm-1 in MeOH) has been found for [Ru(NO)('pyS4')]Br ([1]Br) which contains the parent [Ru(NO)('pyS4')]+ cation ['pyS4'2-= 2,6-bis(2-mercaptophenylthio)dimethylpyridine(2-)]. These ν(NO) shifts can be explained either by an interionic charge-transfer between the bromide anions and the nitrosyl complex cation or by O-O interactions between two NO ligands as found for solid-state [2]Br. These interactions are not found for [1]OTs which exhibits a ν(NO) band at ca. 1890 cm-1 in the solid state (KBr, hostaflon) as well as in MeOH solution.
Darstellung und Strukturanalyse von Lithium- [tetrakis-(methylamino-)aluminat] / Preparation and Crystal Structure of Lithium[tetrakis-(methylamino-)aluminate]
Authors: Rings Sabine , Ischenko Vladislav , Jansen Martin 
Published: February 2015

Abstract
The preparation and spectroscopic data of the new ternary amide LiAl(NHCH3)4 are reported. The structure of the title compound has been determined from X-ray powder diffraction data (tetragonal, 141, a = 14.000(4) Å, c = 9.275(2) Å, 210 reflections, R = 3.75%, weighted R = 5.10%). Both the lithium and the aluminium atoms are coordinated tetrahedrally by nitrogen atoms. Edge-sharing pairs of lithium centered and aluminium centered tetrahedra are connected to each other in helical chains forming a 3D-framework via the remaining vertices. A comparison of the projection of the crystal structure of LiAl(NHCH3)4 along the c-axis to those of cristobalite and of hollandite, (Ba,K)2 (Mn,Fe)8O16, reveals similarities with respect to both the connectivity and the topology of ring structures.
Silylfurane und Bis(silyl)butadiine -Synthese, Lithiumderivate, Kristallstrukturen/ Silylfurans and Bis(silyl)butadiynes - Synthesis, Lithium Derivatives, Crystal Structures
Authors: Neugebauer Peter , Klingebiel Uwe , Noltemeyer Mathias 
Published: February 2015

Abstract
Furan reacts with BuLi and halosilanes to give mono- (1, 5, 7), bis- (2, 6), tris- (3), and tetrakis(2-furanyl)silanes (4); (Fu-R; R = SiMe2Cl (1), SiisoPr2F (5), SitBu2F (7); Fu-R-Fu; R = SiMe2 (2), SiisoPr2 (6); Fu3SitBu (3), Fu4Si (4)), 2,5-Bis(silyl)furans (8, 9) are obtained in the reaction of dilithiated furan and fluorosilanes in a molar ratio 1:2 (R-Fu-R; R = SiisoPr2F (8), SitBu2F (9), 1,4-Bis(di-tert-butylfluorosilyl)butadiyne (10) is formed from furan four equivalents of BuLi, and two equivalents of F2SitBu2. 10 reacts with KOH to give tBu2(OH )Si-C =C -C =C-SitBu2OH (11). Substitution of the fluorine atoms of 5 and 7 by a NH2 group occurs with MNH2 (M = Li, Na). 12 and 13 are obtained. The reaction of 13 with BuLi and tBu2SiF2 leads to the formation of FuSitBu2NHSitBu2F (14) and tBu2Si(NH-SitBu2Fu)2 (15). The lithium derivative of 14 crystallizes as monomer from THF as FuSitBu2N(LiTHF2)SitBu2F and as a dimer containing a four-membered ring (16) from n-hexane (FuSitBu2NSitBu2LiF)2 (17). The crystal structures of 4, 10, 16,17 have been determined.
Synthesis and Structure of a Tetranuclear Nickel Complex of a 40-Membered Macrocyclic Octaamine-Tetrathiophenolate Ligand
Authors: Kersting Berthold 
Published: February 2015

Abstract
The syntheses and characterization of tetranuclear Ni complexes [(L2)Ni4][ClO4]4 (3) and [(L2)Ni4(NCS)4] (4) of a 40-membered macrocyclic octaamine-tetrathiophenolate ligand (L2)4- are described. Single-crystal X-ray structure analysis of 4 reveals well-separated molecules of the tetranuclear isothiocyanate complex [(L2) NiII
4(NCS)4]. The four NiII centers are arranged in binuclear [N2Ni(μ2-SR)2NiN2(NCS)2] subunits containing distorted square-planar NiN2S2 and distorted octahedral NiN2S2(NCS)2 sites. The fact that the two isothiocyanate groups at the octahedral Ni site are in trans positions can be ascribed to the large ring size of the macrocycle
Metallradien, Ionenradien und Wertigkeiten fester metallischer Elemente / Metallradien, Ionenradien und Wertigkeiten fester metallischer Elemente
Authors: Trömel Martin 
Published: February 2015

Abstract
Metallic radii rm are correlated with the ionic radii ri by linear relationships. For groups 1 up to 7 as well as for AI, Ga, In, Tl, Sn, and Pb the ionic radii refer to the maximum valences (oxidation states) as known from compounds according to rm ≈ 1.16 • (ri + 0.64) [Å], For groups 8 up to 12, rm ≈ 0.48 · (ri + 2.26) [Å] with valences W = 14 -G (G = group number). These valences are considered regular (Wr). For groups 1 up to 12, they obey the equation Wr = 7 -[G -71]. According to this equation all outer s electrons and the unpaired d electrons should be involved in chemical bonding, i.e. in the cohesion of the element in the solid state. From the melting temperatures and the atomic volumes it is concluded, however, that only 19 out of the 30 d-block elements have regular valences, namely the elements of groups 3, 5, 6, 10, 11 as well as Os, Ir, Zn, Cd, and possibly Ru. All of the non-regular valences are lower than the regular ones. Four of them are integers: Mn 3; Fe, Co 4; Re 6.
A Diazenidoborate: Formation and Structure of Cs[(CF3)3BN=NCF3]
Authors: Brauer D. J. , Bürger H. , Chebude Y. , Pawelke G. 
Published: February 2015

Abstract
Cs[(CF3)3BNH2] reacts with CF3NO to form cesium trans-trifluoromethyldiazenido-tris(trifluoromethyl) borate Cs[(CF3)3BN=NCF3] (2), the structure of which has been investigated by single-crystal X-ray diffraction. The diazene nature of the anion is confirmed by the length of the N=N bond, 1.231(6) Å, and the size of the N-N-B angle, 115.5(4)° - the B-N bond length being 1.559(7) A. Compound 2 is hitherto the first diazenidoborate which has been fully characterized
The Crystal Structure of Bi3Se4Br
Authors: Petasch U. , Söhnel T. , Oppermann H. , Eggenweiler U. , Keller E. , Krämer V. 
Published: February 2015

Abstract
The crystal structure of Bi3Se4Br has been determined. With respect to its (Bi,Se) substructure it is related to orthorhombic Bi2Se3 and to Bi19S27Br3
A Conformational Study of 5,10,15,20-Tetraalkyl-22H+,24H+-porphyrindiium Salts (Dication Salts)
Authors: Senge Mathias O. 
Published: February 2015

Abstract
N-protonation of 5,10,15,20-tetraalkylporphyrins with n-butyl, isobutyl, isopropyl, 1-ethyl-propyl or tert-butyl substituents yields the respective 22,24-dihydroporphyrins (22H+,24H+-porphyrindiium salts) that exhibit highly nonplanar conformations. Depending on the steric demand of the meso substituents, the free base porphyrins have planar to moderately ruffled macrocycles (primary or secondary alkyl residues) or are severely ruffled (tertiary alkyl resi­dues). X-ray crystallographic studies show that protonation of porphyrins with n-Bu (2), i-Pr (3) or EtPr (4) substituents leads to steric congestion of the core resulting in symmetric, saddle distorted macrocycles as evidenced by average displacements of the Cb positions from the mean plane ranging from 0.79 to 1.01 Å. The structures observed for these porphyrin diacids are very similar in distortion mode and degree of nonplanarity to 5,10,15,20-tetraaryl-22H+,24H+-porphyrindiium salts and to 2,3,7,8,12,13,17,18-octaalkyl-5,10,15,20-tetraaryl-porphyrins. In contrast, protonation of the highly ruffled 5,10,15,20-tetrakis(teA-r-butyl)porph-yrin results in a switch of the conformational distortion mode. The dication 6 shows both saddle distortion (Cb displacements -1.3 Å) and ruffling of the macrocycle (Cm displacements of approx. 0.48 Å). Thus, the need to accomodate four N-H units in the porphyrin core with its associated out-of-plane tilting of the pyrrole rings and the steric strain induced at the meso carbon atoms results in a highly nonplanar porphyrin with mixed distortion modes.
Coprinol, a New Antibiotic Cuparane from a Coprinus Species
Authors: Johansson Martin , Sterner Olov , Labischinski Harald , Anke Timm 
Published: February 2015

Abstract
Coprinol, a new antibacterial cuparane, was isolated from fermentations of a Coprinus sp. Its biological activities were investigated and its structure was elucidated by spectroscopic methods. The new antibiotic exhibited activitiy against multidrug-resistant Gram -positive bacteria in vitro. Two derivatives were synthesized and their activities compared to the parent compound.
Electronic Property and Reactivity of (Hydroperoxo) Metal Compounds
Authors: Nishida Yuzo , Nishino Satoshi 
Published: February 2015

Abstract
DFT calculations were done for the (hydroperoxo)metal complexes with η1-coordination mode, where metal ions are Fe(III), Al(III), Cu(II) and Zn(II). Results shows that 1) the electron density at the two oxygen atoms of the hydroperoxide ion is highly dependent on the angle O-O-H in M-OOH species and the difference in electron density between the two oxygen atoms reaches a maximum at the angle O-O-H = 180°, 2) total electron density at the two oxygen atoms of the peroxide ion increases by approach of methane to the (hydro-peroxo)metal species in the cases of Fe(III) and Cu(II); on the other hand, significant decrease of the electron density on peroxide oxygen atoms was observed for the cases of Al(III) and Zn(II) compounds. These findings suggest that the (hydroperoxo)metal species acts as an electrophile in the former cases (M = Fe(III), Cu(II)) and as a nucleophile for the latter two compounds (M = Zn(II), Al(III)). The electrophilicity observed for the Fe(III) and Cu(II) complexes is attributed to the presence of unoccupied-or half-filled d-orbitals interacting with the hydroperoxide ion. 3) Two oxygen atoms of the (hydroperoxo)-com-pounds of Fe(III) and Cu(II) complexes exhibit quite different reactivity toward the substrate, such as methane. When methane approaches the oxygen atom which is coordinated to a metal ion, a strong decrease of electron density at the methane carbon atom occurs with concomitant increase of electron density at the peroxide oxygen atoms inducing its hetero-lytic O-O cleavage. When methane approaches the terminal oxygen atom, an oxidative coupling reaction occurs between peroxide ion and methane; at first a nucleophilic attack by the terminal electron-rich oxygen atom occurs at the carbon atom to induce C-O bond formation, and a subsequent oxidative electron transfer proceeds from substrate to the metal-peroxide species yielding CH3 -OOH, CH3OH, or other oxidized products. These results clearly de­monstrate that the (hydroperoxo)-metal compound itself is a rather stable compound, and activation of the peroxide ion is induced by interaction with the substrate, and the products obtained by the oxygenation reaction are dependent on the chemical property of the sub­ strate, redox property of a metal ion, and stability of the compounds formed in the intermediate process.
Micellization Process -Temperature Influence on the Counterion Effect
Authors: Różycka-Roszak Bożenna , Żyłka Romuald , Sarapuk Janusz 
Published: February 2015

Abstract
The micellization process of dodecyltrimethylammonium chloride (DTAC) and bromide (DTAB) was studied at 313 K. Nuclear magnetic resonance and calorimetric methods were used. The calorimetric titration curves permitted determination of the critical micelle concentration (CMC) and enthalpy of the micellization process (ΔHm) of the compounds studied. The results obtained were compared to those obtained at 298 K. It was found that calorimetric curves obtained at 313 K for both compounds were similar to each other in contrast to 298 K. Especially a great difference in the shape of curves was observed for DTAC. NMR (1H NMR and 13C NMR) spectra were taken below and above the CMC values and chemical shifts (6) analysed as a function of concentration of the compounds. Comparison of chemical shift-concentration plots with those obtained from measurements performed at lower temperature showed that chemical shifts are of very similar character in both cases for analyzed groups. However, there are some quantitative differences that indicate at smaller difference in hydration of DTAB and DTAC micelles at elevated temperature. This may be the reason of decrease of differences between micellization processes of DTAC and DTAB compounds. The smaller hydration may be, in turn, the result of diminishing differences in physicochemical properties of bromide and chloride ions with temperature.
A New Pyoverdin from Pseudomonas aeruginosa R'
Authors: Ruangviriyachai Chalerm , Fernández Diana Uría , Fuchs Regine , Meyer Jean-Marie , Budzikiewicz Herbert 
Published: February 2015

Abstract
From a Pseudom onas aeruginosa hospital isolate a new pyoverdin was isolated. It is iden­tical with that of Pseudomonas aeruginosa strain R except that in the peptide chain L-Gln is missing.
Sesquiterpene Lactones from Achillea chrysocoma and Achillea coarctata
Authors: Todorova Milka , Tsankova Elena 
Published: February 2015

Abstract
The aerial parts of A. chrysocoma and A. coarctata afforded 22 and 9 sesquiterpene lactones, respectively. All the compounds described are new for the studied species. The lactones 5, 6 and 12 are new for the genus Achillea.
Physiological Activity of Some Aminophosphonates
Authors: Bielecki Krzysztof , Dziamska Anna , Sarapuk Janusz 
Published: February 2015

Abstract
Influence of some new am inophosphonates on electrolyte leakage from cucumber (Cucu­-mis sativus cv "Wisconsin") cotyledons as well as on the content of chlorophyll and activity of guaiacol and pyrogallol peroxidase were studied. Concentration of malondialdehyde (MDA), one of the end-products of lipid peroxidation, was also measured. It was found that am inophosphates influenced the parameters observed to various extents, depending on their structural features and the concentration used. Most active modifiers were those possessing sufficiently long hydrocarbon substituents at the nitrogen atom and/ or iso-propyl chain at the phosphorus atom.
Activation of Isoflavone Biosynthesis in Excised Cotyledons of Lupinus Seedlings by Jasmonoids and Excess Light
Authors: Katagiri Yasufumi , Hashidoko Yasuyuki , Ibrahim Ragai K. , Tahara Satoshi 
Published: February 2015

Abstract
Exogenous jasmonic acid (JA) and methyl jasmonate (MJ) induced accumulation of isofla­ vone constituents in cotyledons prepared from imbibed seeds of white lupin (Lupinus albus L.). Exogenous 0.2 mᴍ MJ enhanced the levels of 7-O-(6″-O-m alonyl)glucosylgenistein and 7-O -glucosylgenistein in the cotyledons of etiolated seedlings that had been incubated in the dark for 48 h. Regarding isoflavone induced by excision and slicing in the cotyledons as background level, the effect of light was 2-to 3-fold higher than that of 0.2 mᴍ MJ. C otyle­ dons exposed to MJ along with a 24-h light period displayed a higher level of isoflavone accumulation than that o f light alone. Total molar amounts of isoflavone accumulated in the cotyledons treated with MJ under continuous light were approximately the sum of those induced by MJ alone and light alone, respectively. The additive-like effect of MJ and light on isoflavone accumulation in lupin tissues suggested the presence of two different signaling systems independently responsible for those two stimuli. Excised cotyledons from etiolated yellow lupin (L. luteus L. cv. Topaz) seedlings also supported this hypothesis. The cotyledons could accumulate both an isoflavone and a flavone, and MJ selectively increased some of the isoflavone constituents, whereas light enhanced the levels of both. The selective accumulation mechanism of isoflavonoids in cotyledons, in which jasmonoids are involved, clearly differed from that activated by light.