bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Crystal Structures of 1-Alkoxy-3-alkylimidazolium Salts Including Ionic Liquids, 1-Alkylimidazole 3-oxides and 1-Alkylimidazole Perhydrates
Authors: Laus Gerhard , Schwärzler Alexander , Bentivoglio Gino , Hummel Michael , Kahlenberg Volker , Wurst Klaus , Kristeva Elka , Schütz Johannes , Kopacka Holger , Kreutz Christoph , Bonn Günther , Andriyko Yuriy , Nauer Gerhard , Schottenberger Herwig 
Published: August 2018

Abstract
Functionalized quaternary imidazolium salts were prepared with the intention to obtain new ionic liquids (ILs). Thus, more than forty 3-alkoxy-1-alkylimidazolium salts, 3-alkoxy-1-alkyl-2-methylimidazolium salts, 1-methylimidazole 3-oxide and 1,2-dimethylimidazole 3-oxide as well as their salts, 1,3-dihydroxyimidazolium salts and 1,3-dihydroxy-2-methylimidazolium salts were synthesized and characterized by spectroscopy and, to a limited extent, by viscosity and conductivity measurements. Results of fourteen single crystal X-ray structure determinations are reported, among them also the parent compounds 1-hydroxyimidazole 3-oxide and 1-hydroxy-2-methylimidazole 3- oxide. Selective debenzylation of 1-benzyloxy-3-methyl imidazolium salts and mono-demethoxylation of 1,3-dimethoxyimidazolium salts were achieved by hydrogenolysis. In addition, a crystalline semiperhydrate of 1,2-dimethylimidazole was characterized. Furthermore, an addition compound of 1-methylimidazole 3-oxide with tris(2-thienyl)borane and a silver carbene complex derived from 1-benzyloxy-3-methylimidazolium hexafluorophosphate was crystallized and characterized.
Cotonoates A and B, New Aromatic Esters from Cotoneaster racemiflora
Authors: Khan Shafiullah , Yasmeen Shazia , Afza Nighat , Malik Abdul , Iqbal Lubna , Lateef Mehreen 
Published: August 2018

Abstract
Phytochemical investigation of the chloroform soluble fraction of the methanolic extract of Cotoneaster racemiflora resulted in the isolation of two new aromatic esters named cotonoates A (1) and B (2) along with the known compound methyl 3,4-dihydroxy-5-methoxybenzoate (3). The structures of the new compounds have been assigned on the basis of spectral analysis including 1D and 2D NMR techniques. Compound 3 shows significant antioxidant and lipoxygenase inhibitory activities.
Ab initio Calculations of Electronic Band Structure and Charge Densities of Zinc Blende-type GaN, BN and Their Solid Solution B0.5Ga0.5N
Authors: Riane Rabah , Matar Samir F. , Hammerelaine Lahcene 
Published: August 2018

Abstract
First principles calculations of the electronic band structures of zinc blende-type GaN and BN and their 1 : 1 mixture B0.5Ga0.5N were carried out within DFT using the augmented plane wave method with both GGA and LDA approximations for the effects of exchange and correlation. Equilibrium lattice constants were determined from the total-energy minimization method. The results are compared with those of previous calculations and with experimental measurements. In agreement with these data, ZB-BN is an indirect (Γ → X) wide-gap semiconductor (4.35 eV) while ZB-GaN has a direct gap of 1.9 eV at Γ . For ZB B0.5Ga0.5N we predict a direct band gap of 3.35 eV. Electron charge densities are computed for the unit cell, and ionicity factors are derived for all systems.
Metal Complexes of Biologically Important Ligands, CLXX [1]. Attachment of Unprotected Aminomonosaccharides and of 1,2-Diaminocyclohexane to Palladium(II) and Platinum(II) through Amino Acid and Peptide Residues
Authors: Ehrenstorfer-Schäfers Eva-Maria , Altman Janina , Beck Wolfgang 
Published: August 2018

Abstract
The reactions of unprotected D-glucosamine with N-coordinated, activated amino acid ester ligands (glycine, diglycine, histidine) of platinum(II) and palladium(II) complexes afford cis- and trans- Cl2Pt(NH2CH2CONHR), trans-Cl2Pt(NH2CH2CONHCH2CONHR)2 and Cl2Pd(histNHR)2 (R = sugar residue) as products. 1,2-Diaminocyclohexane reacts with the activated esters of cis-Cl2Pt- (NH2CH2COOH)2, cis-Cl2Pt(triglyOH)2, cis-Cl2Pt(metOH) and cis-Cl2Pd(histOH) to give dinuclear complexes Cl2Pt[(gly)nNHC6H10NH(gly)n]2PtCl2 (n = 1, 3), Cl2Pt(methNHC6H10NHmeth)- PtCl2 and Cl2Pd(histNHC6H10NHhist)PdCl2.
Electroreduction of Organic Compounds, 36 [1]. Electroreduction of Chlorinated Methyl Benzoates
Authors: Gassmann Jörg , Voss Jürgen 
Published: August 2018

Abstract
The preparative electroreduction of the three methyl monochlorobenzoates, the six methyl dichlorobenzoates, and methyl 2,3,4-trichlorobenzoate in different solvent-supporting electrolytes (SSE) was studied. The rate of the dechlorination, which is the main reaction, is dependent on the substitution pattern. Pronounced regioselectivity is therefore observed in case of the oligochloro derivatives. Hydrogenation of the benzene ring and reduction of the methoxycarbonyl group with formation of a hydroxymethyl group are observed as side-reactions. Quantum chemical calculations on the reaction mechanism were performed. The theoretical results are in accordance with the experimental observations.
Structure, Spectroscopic Study and ab initio Calculations on Third-order Nonlinear Optical Behavior of N-(2-Hydroxy-4-methoxybenzylidene)-3- nitroaniline
Authors: Üver Hüseyin , Karaka§ Aslı , Elmalı Ayhan , Durlu T. Nuri 
Published: August 2018

Abstract
N-(2-hydroxy-4-methoxybenzylidene)-3-nitroaniline (1) has been synthesized and characterized by X-ray diffraction analysis, FTIR and 1H NMR spectroscopy. The maximum one-photon absorption (OPA) wavelengths recorded by quantum mechanical computations using a configuration interaction (CI) method are estimated in the UV region to be shorter than 450 nm, showing good optical transparency to the visible light. We have computed both dispersion-free (static) and also frequency-dependent (dynamic) linear polarizabilities (α) and second hyperpolarizabilities (γ) by using the time-dependent Hartree-Fock (TDHF) method to provide an insight into the microscopic third-order nonlinear optical (NLO) behavior of the title compound. The ab initio calculation results with non-zero values on (hyper)polarizabilities indicate that the synthesized molecule might possess microscopic third-order NLO phenomena.
A Photoluminescent zig-zag 1D Coordination Polymer with Mixed Ligands [Zn(absa)(pcih)](CH3OH)
Authors: Li Dong-Qing , Liu Xing , Zhou Jian 
Published: August 2018

Abstract
A novel 1D zinc(II) coordination polymer [Zn(absa)- (pcih)](CH3OH) (1) (Habsa = 4-aminobenzenesulfonic acid, Hpcih = 2-pyridinecarbaldehyde isonicotinoylhydrazone) has been synthesized by solvothermal reaction at 72 °C and structurally characterized. Each Zn2+ ion is five-coordinated by three N atoms and one O atom from two pcih ligands, and one O atom of an absa ligand, forming a distorted squarepyramidal geometry. Zn2+ ions are bridged by pcih ligands in a zig-zag arrangement generating infinite chains with appended absa ligands. Photoluminescent studies have shown that 1 exhibits an emission at 535 nm (λex = 492 nm).
The influence of alkali-metal ions on the molecular and supramolecular structure of manganese(II) complexes with tetrachlorophthalate ligands
Authors: Wang Hong-Dan , He Ming-Yang , Chen Qun , Chen Sheng-Chun 
Published: August 2018

Abstract
In our efforts to investigate the influence of alkali-metal ions on the formation of metal complexes with polyhalogen-substituted benzenedicarboxylates, two manganese(II) complexes of tetrachlorophthalic acid (1,2-H2BDC-Cl4), [Mn2(1,2-BDC-Cl4)2(H2O)9]·H2O (1) and [MnK2(1,2-BDC-Cl4)2(H2O)4]
n
(2), were synthesized and structurally characterized. Single-crystal X-ray diffraction studies have revealed that complexes 1 and 2 crystallize in space groups P1̅ and Pbcn, respectively. Complex 1 shows a discrete dinuclear structure, while complex 2 features a two-dimensional heterometallic framework containing rare Mn–O–K linkages. The results clearly suggest that the introduction of alkali metal ions does play a critical role in the construction of complexes 1 and 2 with distinct dimensionality and connectivity. Their spectroscopic, thermal, and fluorescence properties have also been studied briefly.
2-Ethyl-1-phenylindazolium hexafluorophosphate. N-heterocyclic carbene formation, rearrangement, ring-cleavage reactions, and rhodium complex formation
Authors: Guan Zong , Gjikaj Mimoza , Schmidt Andreas 
Published: August 2018

Abstract
2-Ethyl-1-phenylindazolium hexafluorophosphate was deprotonated by potassium 2-methyl-butan-2-olate to give the N-heterocyclic carbene of indazole, i.e., indazol-3-ylidene. This N-heterocyclic carbene undergoes a ring transformation to 9-ethylaminoacridine. Trapping of the carbene with sulfur, silver(I) oxide, and carbonylbis(triphenylphosphane)rhodium(I) chloride resulted in the formation of indazolethione, indazolone (X-ray structure analysis), and carbonylbis(triphenylphosphane)(2-ethyl-1-phenyl-1H-indazol-3-ylidene)rhodium(I) hexafluorophosphate (X-ray structure analysis), respectively. Reaction of the indazolium salt with phenolate and thiophenolate gave an N-ethyl-2-(phenylamino)benzimidate and benzimidothioate, respectively.
Hydrometallation of amino-dialkynylgermanes – a gallium hydride oligomer and intramolecular Lewis acid-base interactions
Authors: Uhl Werner , Tannert Jens 
Published: August 2018

Abstract
The compound H5C6(H)Ge[C(GaCMe3)=C(H)CMe3]2(μ-H)3[Ga(CMe3)2], 2, was isolated in trace quantities from the reaction of Et2N–Ge(C≡C–CMe3)3 with excess H–Ga(CMe3)2. Compound 2 has a unique molecular structure with a Ga3H3 heterocycle of which one Ga–H–Ga group is bridged by a dialkenylgermanium unit. The molecular structure of a second compound (3) is reported, which may be described as a spiro-germane and has AlNGeC and AlC2Ge heterocycles. The rings are formed by intramolecular Al–N and Al–C interactions.
Crystal structure of the europium(II) aluminate Eu3Al2O6
Authors: Niehaus Oliver , Pöttgen Rainer 
Published: August 2018

Abstract
Well-shaped single crystals of the europium(II) aluminate Eu3Al2O6 were obtained as a side product during a synthesis attempt for EuCdAl. The structure was refined from single crystal X-ray diffractometer data of a twinned specimen: Ca3Al2O6 type,

P
a

3
¯

,

$Pa\bar 3,$

a
=1584.82(2) pm, wR
=0.0570, 2034 F
2 values, and 103 variables. All aluminium atoms in the Eu3Al2O6 structure show tetrahedral oxygen coordination, and the AlO4 tetrahedra (173–178 pm Al–O) are condensed via common corners to two-dimensional networks. The six crystallographically independent europium sites have coordination numbers 6, 7, 8, and 9, and their europium–oxygen polyhedra are linked with the AlO4 tetrahedra to a dense packing. Bond-valence calculations reveal two sets of differently bonded europium atoms.
Regulation der Chlorophyllbiosynthese. Lidit- und entwicklungsbedingte Aktivitätsänderungen von vier aufeinander folgenden Enzymen der Porphyrin- und Chlorophyllbiosynthesekette / Regulation of Chlorophyll Biosynthesis. Changes in Activity of Four Consecutive Enzymes in the Porphyrin and Chlorophyll Biosynthesis Chain during Development and Illumination
Authors: W. Schneider Hansjörg A. 
Published: August 2018

The activities of enzymes related with chlorophyll and porphyrin synthesis have been examined during development and greening of young corn leaves. The enzymes succinyl-CoA-synthetase (SCoAS), δ-amino-levulinate synthetase (ALAS), δ-amino-levulinate dehydratase (ALAD) and the enzymes involved in porphobilinogenase (PBGA) were under investigaton.
When leaves are illuminated and chlorophyll synthesis begins the activity of ALAD is not influenced. The activity of PBGA and SCoAS are slightly higher than in darkness, but the changes are below the range affecting chlorophyll biosynthesis. ALA, however, is only synthetized in the light. Synthesis ceases immediately when illuminiation ist stopped, indicating'that in darkness ALAS is not active. On the other hand ALAS is active in dark grown roots, tubers and other non-leaf tissues.
Feeding the plant with succinate, glycine or α-keto-glutarate has no effect on chlorophyll synthesis, but the amount of ALA is reduced, whereas sucrose promotes its accumulation. The results are discussed with completely antitethaal results obtained with tissue cultures of tobacco and are integrated into a scheme which excludes the contrariety of hypotheses deduced from experi- ments with inhibitors of protein and nucleic acid synthesis. It is suggested that the varying results are caused by the action of light on different stages in differentiation of plastids and cells.
In contrast to the enzymes SCoAS, ALAD and PBGA whose activities were determined in vitro, ALAS was assayed in vivo by means of the accumulation of (5-amino-levulinate (ALA) after blocking the enzyme ALAD by levulinate (LA). Optimum accumulation is observed when the concentration is about 2 · 10-2 м. LA is not converted to ALA in appreciable amounts. This could be proved by feeding the plants with 14C-LA which was prepared from uniformly labeled 14C-fructose.
Zur Chemotaxonomie der Alkenvögel. Die Zusammensetzung der Bürzellipide des Tordalks (Alca torda), der Trottel- und Ringellume (Uria aalge) und der Gryllteiste (Cepphus grylle) / Chemotaxonomy of Alcidae. The Composition of the Uropygial Gland Fat from the Razorbill (Alca torda), Guillemot (Uria aalge) and the Blade Guillemot (Cepphus grylle)
Authors: Jacob Jürgen , Zeman Alfred 
Published: August 2018

The uropygial gland fats from the razorbill, guillemot (two varieties) and the black guillemot arc very complex mixtures of ester waxes. Among the wax acids n- octanoic acid dominates followed by homologous series of 2-, 4- and 6-monomethyl-, 2,6-, 2,8-, 2,10-, 4,6-, 4,8-, 4,10-, 4,12-dimethyl- and 2,4,8-, 2,6,10-, 2,6,12-, 4,6,10- and 4,8,12-trimethyl-substituted fatty acids. The alcoholic components consist of n-, 2-, 4-, 6-, 8- and 12-monomethyl- as well as 2,6-, 2,8-, 2,10-, 4,6-, 4,8-, 4,10- and 4,12-dimethyl-branched alkanols.
The black guillemot differs from the other species investigated by the occurence of fatty acids which have the first branch in 2- while the others start with the 4-position. The chemotaxonomy of the 20th order of the natural system is discussed.
Komplexbildung von Dehydrogenasen mit Coenzymanalogen und Coenzymbruchstücken / Complexformation of Dehydrogenases with Coenzyme Analogues and Coenzyme Fragments
Authors: Scherr Dietmar , Jeck Reinhard , Berghäuser Jürgen , Woenckhaus Christoph 
Published: August 2018

The spectral properties of binary complexes of NAD-analogues and fragments therefrom with I.DH from pig heart or ADH from liver and yeast have been investigated. The NADH-analogues were modified by replacing adenine through benzimidazole, benzene or dihydronicotinamide. Additionally adenosine diphosphate ribose, dihydronicotinamide and dihydronicotinamide- ribose pyrophosphate-5"-ribose have been studied.
It has been shown by means of difference spectra that complexes between ADH from horse liver and analogues cause spectral changes in the region of aromatic absorption at 280 nm even when adenine is absent in the analogues. Spectral changes in the other enzymes mentioned are probably due to changes of the n-π* absorption of the adenine ring. The spectral changes upon complexing indicate hydrophobic interaction of the adenine with the enzyme protein. Fluorescence spectra vary in the intensity of the energy transfer band as well as in coenzyme emission depending on variation of the coenzym analogue. Changing of complex formation between protein and analogues at different pH-values are investigated. ADH from yeast, especially, shows a pK around 6 which suggests interaction with histidine imidazole.
VI. Calcium- und Kaliumionen als Cofaktoren
Authors: Frank Werner 
Published: August 2018

Embryonic rat cells are stopped in G1-phase when they are incubated in serum-free medium. They can be triggered to proceed through their cell cycle by the addition of two proteins which have been isolated from fetal calf serum. The influence of calcium and potassium ions on the stimulation process has been exam ined:
1. Ca2+ and K+ ions simultaneously must be present in the culture medium in concentrations of at least 5x10-4 ᴍ and 1x10-3 ᴍ, resp.
2. The intracellular concentrations of both ions are increased by the serum factors.
3. The intracellular concentrations of K+ strongly are dependent on the extracellular Ca2+-concentrations; they increase threefold between 5x10-5 and 1x10-3 ᴍ of Ca2+. On the other hand, the intracellular calcium concentrations are not significantly influenced by the potassium content of the culture medium.
Deuteriumoxid-induzierte Filamentaggregation im Mikronukleus eines Ciliaten / D2O-Induced Filament Aggregation in the Mioronucleus of a Ciliate
Authors: Hauser Manfred , Beinbrech Gemot 
Published: August 2018

Keywords
The large spindle-shaped micronucleus of Paramecium bursaria contains filaments of about 60 Å diameter between numerous highly condensed chromosomes. Following treatment for several hours with 10% heavy water the nucleus becomes streched to several times its original length. The filaments, whose number increases noticibly, then appear as an aggregate, which exhibits a somewhat paracrystalline arrangement. An examination of the filament aggregate by means of a laser diffractometer yielded two diffraction lines corresponding to longitudinal periodicities of 91 - 99 and 160 -195 Å. Since both periodicities are comparable to those reported for microtubular proteins, it is assumed the filaments reported here could be related to microtubular material.
Bifunctional Photobinding of Psoralen to Single Stranded Nucleic Acids
Authors: Marciani S , Terbojevich M. , Dall 'Acqua F , Rodighiero G. 
Published: August 2018

Abstract
As psoralen and other furocoumarin derivatives, intercalated between two base pairs of native DNA, under irradiation at 365 nm form inter-strand cross-linkings as a consequence of bifunctional addition, the writers have investigated the ability of psoralen to give such bifunctional photo­ additions, too, with nucleic acids with disordered or partilly disordered structure (denatured DNA and r-RNA).
On the basis of fluorimetric, light-scattering, viscosimetric measurements and of the renaturation ability of denatured bacterial DNA, certain results have been obtained. In addition to monofunctional photoadditions, psoralen can give bifunctional binding by irradiation at 365 nm both with denatured DNA and with r-RNA. However, when irradiation of denatured DNA in the presence of psoralen was performed in a concentrated solution (0.4%), the formation of bifunctional additions between two different strands was demonstrated by the increase (50%) of molecular weight of denatured DNA. However, when irradiation of denatured DNA was performed in more dilute solutions (0.1%), the bifunctional photoaddition of psoralen took place producing only bi­ functional additions in the same strand, very probably with the formation of loops, as has been shown by the absence of increase of molecular weight of DNA and by the more restricted structure assumed by the macromolecule, revealed by the light-scattering and viscosimetric measurements. The formation of these bifunctional additions was confirmed by the reduced rate of renaturation shown by denatured bacterial DNA after irradiation in the presence of psoralen.
In the case of r-RNA, psoralen, when irradiated can form bifunctional additions only in the same strand.
Effect of the Protons Arising in Aqueous Hydrolysing ATP Solutions, IR Investigations
Authors: Hofmann Klaus P. , Zundel Georg 
Published: August 2018

Abstract
IR spectra of 0.3 ᴍ aqueous solutions of Mg0.5K3-nHMn ATP were plotted. The dependence of the spectra on the hydrolysis was investigated for three different K/H ratios of the nonhydrolysed system. Changes to bands provide information as to the protons added to the phosphate groups and base residues as a function of the initial protonation and degree of hydrolysis. More and more proton addition to the -PO3
-- groups is observed as the initial protonation increases and as the degree of hydrolysis rises. The same applies as far as the addition of protons to the base residues is concerned to the systems with a higher initial protonation. At low degrees of hydrolysis the PO4
3- ions which occur do not bind the two hydrolysis protons completely. 150% protonated PO4
3- ions first form which cross-like via OH+···O hydrogen bonds, which only become more strongly protonated in the systems with a higher initial protonation at large degrees of hydrolysis. The OH+···O bonds between the 150% protonated hydrogen phosphate ions as well as the NH+···N hydrogen bonds between the base residues cause an IR continuum and are thus easily polarizable. An extremely large change to the hydrate structure within narrow hydrolysis ranges is indicated by changes to the bands of the water molecules. The biological relevance of these findings is briefly discussed in the conclusions.
Iridoide und Ecdysone aus Verbenaceae, VI1 . Stilbericosid, ein neues C8-Iridoid aus Stilbe ericoides L. / Iridoids and Ecdysones from Verbenaceae, VI1 . Stilbericoside, a New C8-Iridoid from Stilbe ericoides L.
Authors: Rimpler Horst , Pistor Helga 
Published: August 2018

Abstract
Stilbericoside, a new iridoid isolated from Stilbe ericoides, is shown to have structure 1. The relative configuration is deduced mainly from NMR spectra and double resonance experiments. Because of the great similarity of their NMR spectra 1 and unedoside, a known iridoid, which also occurs in Stilbe ericoides, very probably have the same relative configuration. Unedoside therefore should be represented by formula 2 rather than by the hitherto accepted formula 3 .