bluuebunny/crossref_metadata_2025 huggingface dataset:
Darstellung und Eigenschaften von cyclo-Nonaschwefeloxid (S9O) und von cyclo-Dekaschwefeloxid (S10O) [1] / Preparation and Properties of cyclo-Nonasulfuroxide (S9O) and of cyclo-Decasulfuroxide (S10O) [1]
Authors: Steudel Ralf , Sandow Torsten , Steidel Jürgen
Published: March 2015

The homocyclic oxides S9O (m.p. 33 °C, dec.) and S10O (m.p. 51 °C, dec.) have been prepared by oxidation of the corresponding sulfur rings S9 and S10 , respectively, by trifluoroperoxy acetic acid (molar ratio 1:2-3) in a carbon disulfide/methylene chloride mixture. According to infrared and Raman spectra, both compounds contain an exocyclic oxygen atom. S9O and S10O decompose at 25 °C to give SO2 and a polysulfuroxide SnO with >10 but both can be stored at -78 °C without decomposition. The SS bond distances are discussed on the basis of the Raman spectra. In addition, the Raman spectrum of solid S9 has been recorded for the first time. It shows that S9 crystallizes as two allotropes (α-and β-S9) both consisting of cyclic molecules of either C1 or C2 symmetry with bond distances of between 203 and 209 pm.
Siliciumverbindungen mit starken intramolekularen sterischen Wechselwirkungen, XX [1] 1,1-Di-tert-butyl-2,2-dimesityldisilane: Synthese, Molekülstruktur, Radikale / Silicon Compounds with Strong Intramolecular Steric Interactions, XX [1] 1,1-Di-tert-butyl-2,2-dimesityldisilanes: Synthesis, Molecular Structure, Radicals
Authors: Weidenbruch Manfred , Kramer Klaus
Published: March 2015

The sterically congested disilanes tBu2XSiSiXMes2 [X = H (1), X = Cl (2)] have been prepared. An X-ray structure analysis of 1 reveals a preference for the anti-conformation in the solid state. Similar results have been obtained by empirical force field calculations and DNMR spectroscopy. Reaction of 2 with an electron rich olefin leads to a chlorine bridged disilanyl radical whereas treatment with alkali metals yields the corresponding disilenyl radical anion, tBu2Si=SiMes2˙̄.
Darstellung und Eigenschaften von und Reaktionen mit metallhaltigen Heterocyclen, XLVII [1]. Einschiebungsreaktionen von phasentransferkatalytisch in situ erzeugten Dihalocarbenen in P-haltige Manganacycloalkane – Struktur und chemisches Verhalten der Reaktionsprodukte / Preparation and Properties of and Reactions with Metal-Containing Heterocycles, XLVII [1]. Insertion Reactions of Phase-Transfer-Catalytically in situ Generated Dihalocarbenes into P-Containing Manganacycloalkanes – Structure and Chemical Behaviour of the Reaction Products
Authors: Lindner Ekkehard , Zinßer Fritz , Mayer Hermann August , Hiller Wolfgang , Fawzi Riad
Published: March 2015

The phase-transfer-catalytically in situ generated dihalocarbenes CCl2 and CBr2 are inserted into a β-C-H bond of the five-and six-membered phosphamanganacycloalkanes (OC)4[xxx] (1a, b) [n = 1(a), 2(b)] to give the functionalized metallacycles (OC)4[xxx](2a, a′, b, b′) [X = Cl: n = 1(a), 2(b); X = Br: n = 1(a′), 2(b′)]. 2b crystallizes in the orthorhombic space group Pbca with Z = 8 and has a distorted chair conformation with equatorial position of the CHCl2 group. The envelope conformation of 2a in solution was elucidated by means of 1H and 13C{1H} NMR spectroscopic investigations.
Polyine, V [1]. Synthese von (1,3-Alkadiinyl)thioether / Polyynes, V [1]. Synthesis of (1,3-Alkadiynyl)thioethers
Authors: Barz Michael , Himbert Gerhard
Published: March 2015

Lithium 4-thiobutadiynides, Ethynylation, Diacetylenic Thioethers By the reaction of (3,4,4-trichloro-3-buten-1-ynyl)thioethers 2 or of (pentachloro-1,3-butadienyl)thioethers 4 with the twofold or the threefold equimolar amount of n-butyllithium the corresponding lithium butadiynides 5 are prepared. The treatment of these acetylides 5 with water, with the halides of some organyl groups or with chloral, phenylisocyanate, cyclohexyl-isothiocyanate and water furnishes the (butadiynyl)thioethers 6 a-f and 7 a-c. The reaction of the lithium butadiynide 5 a with cyanogen bromide and morpholine leeds via the bromoacetylene 8 to the (4-morpholinobutadiynyl)phenylthioether 9.
Some Reactions with 4-(p-CinnamoylaniIino)quinolines
Authors: Kamel M. M. , Gadalla K. Z. , El-Hamouly W. S. , El-Wassimi M. T.
Published: March 2015

For possible biological activity, the title compounds were prepared and allowed to condense with hydrazine hydrate, phenyl hydrazine, hydroxylamine HCl, urea and thiourea to give the pyrazolines 3, isoxazolines 4, oxo and thioxopyrimidines 5, respectively.
Isolierung und Strukturidentifizierung eines Cyclopropan-haltigen Triterpens aus Euphorbia lactae / Isolation and Structure Identification of a Triterpenoid with a Cyclopropane Moiety from Euphorbia lactae
Authors: Lücke Jürgen , Khan Mohammad Attaulah , Voelter Wolfgang
Published: March 2015

4-Methylcyclo-art-22-ene-3,25-diol was isolated from Euphorbia lactae and its structure identified by elemental analysis, mass spectrometry and proton NMR spectroscopy.
Studien zum Vorgang der Wasserstoffübertragung, 75 [1]. Elektrochemische Untersuchungen von S-und P-vergiftetem Raney-Nickel (Ra—Ni) und Versuche zu dessen Reaktivierung / Studies on the Occurrence of Hydrogen Transfer, 75 [1]. Electrochemical Investigation of Raney-Nickel (Ra—Ni) Poisoned with S and P and Experiments for the Reactivation
Authors: Horner Leopold , Franz Christoph
Published: March 2015

Ra-Ni with an artificial rest potential of -1000 mV (vs SCE) is shifted with different rates to more positive values after the addition of thioethers and carbon disulfide. Only with Na2S·9H2O a potential of -1100 mV (constant) is observed. Ra-Ni poisoned with sulfur is not reactivated neither cathodically nor anodically nor by the corrosive degradation at constant pH.

Hydrogen structurally incorporated into the lattice of Ra-Ni (structural bonded hydrogen) is consumed by poisoning with thioethers and trivalent phosphorus compounds in a stoichiometric way.

Ra-Ni-powder stepwise corrosively degradated up to 30% shows the same degree of desulfuri-zation as the original Ra-Ni. Desactivated Ra-Ni (loss of structural bonded hydrogen) is reacti-vated (56%) by cathodical treatment.

In competing reactions the P-S, C-S, and C -P-bond in thiophosphinic esters, thioethers and trivalent P-compounds are hydrogenolyzed by Ra-Ni, the C-P-bond faster than the C-S-bond.
4,2′-Dihydroxy-3,5-dimethoxybiphenyl, a New Phenol from the Wood of Salix caprea L.
Authors: Malterud Karl E. , Sandanger Dugstad Eva K.
Published: March 2015

The title substance has been isolated in a 0.0003% yield from wood of Salix caprea L. which, after felling, had been kept outdoors for one year. Its structure has been elucidated by spectroscopical and chemical methods.
Dibenzo[b,g]heterocin-5,7-dione / Dibenzo[b.g] heterocine-5,7-diones
Authors: Hellwinkel Dieter , Ittemann Peter , Bohnet Siegbert
Published: March 2015

Dibenzo[b,g]heterocine-5,7-diones are synthesized by intramolecular ester condensations. Ring inversions of their distorted boat conformations occur with activation barriers of 10-15(42-62) kcal(kJ)/mole.
Asymmetrische Katalysen, 25 [1]. C5H5Mn(CO)2-Komplexe von optisch aktiven Chelatphosphanen als einzähnige Liganden in der enantioselektiven Katalyse / Asymmetric Catalyses, 25 [1]. C5H5Mn(CO)2 Complexes of Optically Active Chelate Phosphanes as Monodentate Ligands in Enantioselective Catalysis
Authors: Brunner Henri , Knott Alfons
Published: March 2015

The chelate phosphanes Diphos, Diop, and Norphos were reacted with C5H5Mn(CO)2THF and CH3C5H4Mn(CO)2THF to give mononuclear complexes, containing the phosphanes as unidentate or as bidentate ligands, and dinuclear complexes, containing bridging phosphane ligands. In C5H5Mn(CO)2Diop one of the two P(C6H5)2 groups of Diop is coordinated to the C5H5Mn(CO)2 fragment; the uncoordinated P(C6H5)2 group makes it a monodentate ligand. C5H5Mn(CO)2Diop together with [Rh(cod)Cl]2 was used as an in situ catalyst in the enantioselective hydrogenation of (Z)-a-[N -acetam ino]cinnamic acid (78.4% ee) and in the enantioselective hydrosilylation of acetophenone with diphenylsilane (6.7% ee).
Mehrkernkomplexe aus PH3- und RPH2-Komplexen mit Co2(CO)8 / Polynuclear Complexes from PH3 and RPH2 Complexes with Co2(CO)8
Authors: Lal De Rajib , Vahrenkamp Heinrich
Published: March 2015

The phosphine complexes M-PH3 (1), M-PH2Me (2). M-PH2Ph (3). and M-PH2/Bu (4) with M = Cr(CO)5. Mo(CO)5, W(CO)5, MnCp(CO)2. of which 2 and 4 were prepared for the first time, were reacted with Co2(CO)8. All four PH3 complexes yielded the clusters M-PCo3(CO)9 (5) with external M units as confirmed by a crystal structure determination of (CO)5W-PCo3(CO)9. Of the RPH2 complexes 2 and 3 the chromium and tungsten compounds gave open trinuclear complexes of the type M-PRCo2(CO)7 (6, R = Me: 7, R = Ph). The manganese containing complexes 2 and 3 and Co2(CO)8 formed the dinuclear compounds Cp(CO)2Mn(μ-PRH)Co(CO)3 (8d, R = Me; 9d, R = Ph). The molybdenum containing complexes 2 and 3 yielded unstable compounds of higher nuclearity with Co2(CO)8. The tBuPH2 complexes 4 did not react.
Vier- und fünffach koordinierte Schwefelmonoxid-Komplexe des Rhodiums und Iridiums [1] / Four- and Five-Coordinated Sulfur Monoxide Complexes of Rhodium and Iridium [1 ]
Authors: Schenk Wolfdieter A. , Leißner Johanna , Burschka Christian
Published: March 2015

The complexes trans-[M(PR3)2(SO)Cl] (M = Rh. Ir; R = isopropyl, cyclohexyl) were synthesized from [(C8H14)2MCl]2, PR3 and C2H4SO. The X-ray structure of [Ir(P/Pr3)2(SO)Cl] shows the sulfur monoxide to be coordinated in a bent η1 fashion. A bonding model is pro- posed which explains the similarity between SO- and SO2-complexes. Peracid oxidation trans- forms coordinated SO to SO2. CO displaces SO via isolable 5-coordinated intermediates [Ir(PR3)2(CO)(SO)Cl].
Darstellung und Eigenschaften von und Reaktionen mit metallhaltigen Heterocyclen, XLIX [1]. Untersuchungen zur Chelat-assistierten oxidativen Addition einer C–Cl-Bindung an Rhodium(I)-KompIexe und reaktives Verhalten von Phospha-rhoda-cyclopentanen / Preparation and Properties of, and Reactions with Metal-Containing Heterocycles, XLIX [1]. Investigations on the Chelate Assisted Oxidative Addition of a C–Cl Bond to Rhodium Complexes and Reactive Behaviour of Phospharhodacyclopentanes
Authors: Lindner Ekkehard , Fawzi Riad , Mayer Hermann August
Published: March 2015

The complex L2Rh(CO)Cl (3b) is obtained by reaction of [μ-ClRh(CO)2)2 (1) with L = Cl-[CH2]3-P(C6H11)2 (2b) in benzene at 20 °C. 3b crystallizes in the triclinic space group P1 with Z = 1. On re fluxing 3 b in benzene an oxidative addition of one C-Cl bond to rhodium takes place to give the rhodacyclopentane derivative [xxx] (4b). Not only steric aspects of the ligands L and high electron density of the metal, but also free rotation about the Rh-P axis is important for the oxidative addition. Temperature dependent 31P{1H} NMR spectra of 3b between - 90 and 90 °C exhibit only one doublet in accordance with one rotameric form. Action of PMe3 on [xxx] (4a) [L - Cl-[CH:]; -P(C6HQ2 (2a)] results in the formation of the cyclic acyl compound [xxx] (5a).
CS2, CSSe und CSe2 als Bausteine für ein- und zweikernige Palladium- und Platinkomplexe [1] / CS2, CSSe and CSe2 as Building Blocks for Mono- and Binuclear Palladium and Platinum Complexes [1]
Authors: Werner Helmut , Ebner Martin , Bertleff Werner
Published: March 2015

The compounds Pd(PPh3)4, Pt(PPh3)4 and Pt(PPr3
i)2 react with CS2, CSSe and CSe2 to give the mononuclear complexes (PR3)2M(η2-CEE′). From Pd(PPh3)4 and excess CSe2 the compound (PPh3)2PdC2Se4 is obtained. 1,2-C2H4(PPh2)2 (diphos) and 1,2-C6H4(CH2PPh2)2 (dpmb) react with (PR3)2M(η2-CEE′) by ligand displacement to produce the chelate complexes (diphos)M(η2-CEE′) and (dpmb)M(η2-CEE′), respectively. The reaction of (PPh3)2Pt(η2-COS) with diphos leads to the formation of the carbonyl compound (diphos)Pt(CO). In solution, the complexes (diphos)M(η2-CS2) and (diphos)M(η2-CSe2) slowly dimerise to form products of composition [(diphos)M(CEE′)]2 which probably contain bridging CS2 and CSe2 units. (PPh3)2Pd(η2-CSe2) reacts with PMe3, PMe2Ph and PMePh2 to produce the binuclear compounds [(PR3)Pd(Se2CPR3)]2 in which the zwitterionic ligand PR3CSe2 bridges the two Pd(PR3) fragments. The analogous complexes [(PR3)Pd(SSeCPR3)]2 are prepared from Pd(PR3)4 (PR3 = PMe3, PMe2Ph, PMePh2) and CSSe.
Nukleophile Substitution an Thionyl- und Sulfurylchlorid mit Metallaten. Synthese und Struktur der SO- bzw. S 0 2-Komplexe [(C6H5O)3P]2(CO)2Fe(SOn)(n=1, 2) / Nucleophilic Substitution at Thionyl- and Sulfuryl Chloride by Metallates. Synthesis and Structure of the SO- and SO2-Complexes [(C6H5O)3P]2(CO)2Fe(SOn)(n=1, 2)
Authors: Lorenz Ingo-Peter , Hiller Wolfgang , Conrad Michael
Published: March 2015

The synthesis of the SO- and SO2-complexes 3 and 4 follows equations (1) and (3) by nucleophilic substitution of SOCl2 or SO2Cl2 by the same metallate 2. 4 can also be obtained by simple air oxidation of solutions of 3 according to equation (2). Spectroscopic investigations indicate a trigonal bipyramidal configuration on iron with both phosphite ligands in axial positions and the sulfur oxide ligands in equatorial positions together with both carbonyl ligands. The X-ray structure analysis of the SO2 complex 4 shows the exactly planar coordination of the sulfur atom and the nearly perpendicular orientation of the SO2 plane to the equator plane; thus complex 4 is isolobal to SO3. The SO ligand in 3 coordinates as a 2c-2e-system in a bent structure with both atoms lying in the equatorial plane.
Comment on the Relationship between 1H Chemical Shifts and Net Charges
Authors: Vogler Helmut
Published: March 2015

The relationship between net charges and 1H chemical shifts in cyclic conjugated charged hydrocarbons is investigated by taking into account explicitely ring current and local anisotropic contributions and the effect of ion-pairing.
Synthese, Charakterisierung und Dynamik von [Hg(η1-dppm)3](O3SCF3)2, dppm = Bis(diphenylphosphino)methan / Synthesis, Characterisation and Fluxionality of [Hg(η1-dppm)3](O3SCF3)2, dppm = Bis(diphenylphosphino)methane
Authors: Lusser Maria , Peringer Paul
Published: March 2015

The title compound is formed from [Hg(η1-dppm)2](O3SCF3)2 and dppm, and is fluxional on the NMR time scale as the result of fast intramolecular displacement of coordinated phosphorus by free phosphorus in the η1-dppm ligands; at temperatures above 253 K intermolecular ligand exchange sets in.
Heterocyclische Siebenring-Verbindungen, XXIX [1] Bildung und Abfangreaktionen von substituierten 2,3-Dehydro- 1,5-benzodioxepinen / Heterocyclic Seven-Membered Ring Compounds, XXIX [1] Formation and Trapping Reactions of Substituted 2,3-Dehydro-1,5-benzodioxepins
Authors: Hofmann Hans , Löw Gerhard , Haag Armin
Published: March 2015

4-Cyano- and 4-Carbomethoxy-3,4-dihydro-2H-l,5-benzodioxepin-3-one (1a and 1b) have been converted to the corresponding enol-toluenesulfonates 2a and 2b, respectively. Reaction of 2a and 2b with base led to the heterocyclic allenes 3a resp. 3b, which could be trapped by Diels-Alder-reaction with furane, yielding the cycloadducts 4a and 4b.
Novel Spin Labeled Azacrown Ethers
Authors: Sosnovsky George , Lukszo Jan
Published: March 2015

Four novel spin labeled azacrown ethers contain­ing either endo- or exo-cyclic nitroxyl moieties were synthesized by short and convenient routes. These compounds should be of interest in biological studies of membranes using ESR spectroscopy.
Synthese und Struktur von [Mo(CO)4(TeC6H5)]2 / Synthesis and Structure of [Mo(CO)4(TeC6H5)]2
Authors: Vogt Thomas , Strähle Joachim
Published: March 2015

The reaction of Mo(CO)6 with Ph2Te2 in toluene yields a black amorphous precipitate of Mo„(TePh)3n-3(CO)6 (n ~ 4) as the main product besides smaller amounts of Mo2(CO)8(TePh)2 which can be obtained from the solution as black crystals. They crystallize in the monoclinic space group C2/c with the lattice parameters a = 1872.0 pm, b = 751.9 pm, c = 1741.6 pm, β = 103.14°, Z = 4. In the dinuclear complexes of symmetry Q the Mo atoms are bridged by two TePhligands. The octahedral coordination of each Mo atom is completed by four CO groups. Mo -Mo interaction is indicated by a distance of Mo-Mo = 311.4 pm and a small bond angle Mo - Te - Mo = 69.14°
Pyridin-Addukte von Cyclothiazeno-Vanadiumdichlorid Die Kristallstruktur von [VCl2(N3S2)(C5H5N)] / Pyridine Adducts of Cyclo-thiazeno Vanadium Dichloride The Crystal Structure of [VCl2(N3S2)(C5H5N)]
Authors: Christophersen Ruth , Klingelhöfer Paul , Müller Ulrich , Dehnicke Kurt
Published: March 2015

The pyridine complexes of cyclo-thiazeno vanadium dichloride, [VCl2(N3S2)py] and [VCl2(N3S2)(py)2] were synthesized by reactions of polymeric VCl2(N3S2) with varying amounts of pyridine in CH2Cl2. The compounds were characterized by their IR spectra as well as by their 51V NM R spectra. The crystal structure of [VCl2(N3S2)(C5H5N)] was determined by means of X-ray diffraction (1582 independent observed reflexions, R = 0.031). Crystal data: orthorhombic, space group Pnma, a = 1372, b - 2261, c - 1068 pm, Z = 12. In the lattice there are two monomeric, crystallographically independent molecules [VCl2(N3S2)(C5H5N)], which differ only slightly. The vanadium atoms have a trigonal bipyramidal coordination with the N atom of the pyridine molecule and one chlorine atom in apical positions, and with one chlorine atom and the N atoms of the cyclo-thiazeno ligand in equatorial positions. The VN bond lengths of the planar VN3S2 ring of 174 pm correspond to double bonds
Lineare Oligophosphaalkane, XII [1] PH-funktionelle Methylenbisphosphane — eine Quelle für Phosphinidene und Phosphoratome in Clustern und Fe4P-Spiroverbindungen / Linear Oligophosphaalkanes, XII [1] PH-Functional Methylenebisphosphanes — a Source of Phosphinidenes and Phosphorus Atoms in Clusters and Fe4P Spiro Compounds
Authors: Brauer David J. , Hietkam Sibbele , Sommer Herbert , Stelzer Othmar
Published: March 2015

On reacting PH-functional m ethylenebisphosphanes (iPr)HPCH2PH2 (1) and RHPCH2PR2 (R = CH2Ph) with excess Fe2(CO)9 P -C -P-bond cleavage occurs. As a result β-phosphido bridged clusters e.g. Fe3(CO)8(μ2-PRCH2PR2)(μ3-PR)(μ2-H) (11) and Fe4(μ4-P) spiro com pounds with naked phosphorus atoms Fe4(CO)13(μ4-P)(μ2-PRCH2PR2) (10) or Fe4(CO)14(μ4-P)(μ2-P(/Pr)Me) (6) are obtained. Uptake of one molecule of CO by 11 and ametallation of one CH2Ph substituent within the PR2 donor group yields 12. Compound 10 • CH2C12 crystallizes in the space group C21/c with a = 36.357(7), b = 10.752(2), c = 22.879(5) Å , β - 112.45(1)°, Z = 8 {R = 0.050 for 5213 reflections). Both the phosphido atoms of the μ2- PRCH2PR2 group and the μ4-P atom span the Fe1 -Fe2 bond of a Fe2(CO)6 species while only the μ4-P atom spans the Fe3 -Fe4 bond of a (CO)4FeFe(CO)3 fragment. In addition, the Fe(CO)3 part of the latter unit is bonded to the tertiary P atom of the μ2-PRCH2PR2 group. Compounds 11 and 12 cocrystallize in the space group P1 with a = 11.541(2), b = 17.739(2), c - 19.284(2) Å , a = 78.01(1), β = 78.68(1), y = 90.36(1)°, Z = 2 of each (R = 0.051 for 10234 reflections). A(CO)3Fe -Fe(CO)2-Fe(CO)3 core having an acute Fe11-Fe12 -Fe13 angle of 77.46(3)° at the Fe(CO)2 group is found for 11. The Fe12 - Fe13 bond is bridged by both the ,μ3-PR group and the hydride ligand. The Fe 11 -Fe 13 contact is spanned by the μ3-PR ligand and the ,μ2-P atom of the ,m2-PRCH2PR2 species. Three Fe(CO)3 groups are bridged by the μ3-PR ligand in 12. Only two of the Fe(CO)3 groups appear to be directly bonded. Fe21 -Fe23 is bridged by the μ2-P atom of the ,μ2-PRCH 2PRCHPh ligand while Fe22 -Fe23 displays a novel Fe22 - P - C -Fe23 linkage
Die Fluoreszenzlöschung von oberflächenadsorbierten Farbstoffen durch Sauerstoff kann von der Viskosität des Mediums vor der Oberfläche unabhängig sein / Fluorescence Quenching of Dyes Adsorbed on Surfaces by O2 May be Independent on the Viscosity of the Medium in Front of the Surface
Authors: Burkhard Oswald , Barnikol Wolfgang K. R.
Published: March 2015

The application of v. Smoluchowski’s theory concerning diffusion controlled reactions to the O2 quenching of fluorescent dyes adsorbed on surfaces predicts that the viscosity of the medium in front of the surface has a considerable influence on the fluorescence intensity. We have studied pyrene adsorbed on polystyrene grains and got the experimental result that changing the medium in front of the surface from a gas phase to water is not accompanied by a change of the quenching behaviour. This result is clearly in contrast to the theoretical predictions. In our opinion the discrepancy may be explained by the special conditions the dye molecule at the surface experiences. We assume that the pyrene molecules are situated in some small groves of the polystyrene grains and that the properties of the medium within those groves are responsible for fluorescence quenching by O2. The medium in front of the surface cannot get into the groves
Diels- Aider- Addukte des Diphosphens F3CP = PCF3 / Diels-Alder Adducts of the Diphosphene F3P =PCF3
Authors: Grobe Joseph , Van Duc Le , Schulze Joachim
Published: March 2015

The heterocycles 3 to 6 are formed in a one-pot procedure by reacting trifluoromethyl phosphorus diiodide F3CPI2 with tin dichloride SnCl2 in the presence of the corresponding 1,3-dienes. The reactions proceed via [2+4] cycloaddition of the diphosphene intermediate F3CP = PCF3 (1) as suggested by the high yields obtained (50 to 100%) and the formation of the cyclic tetraphosphane (F3CP)4 (2) as the only by-product. Cycloreversion occurs at moderate temperatures as demonstrated by the reaction of 6 with 2,3-dimethylbutadiene to give 3 and cyclohexadiene. The products have been characterized by NMR and mass spectra
Metallkomplexe mit Hexamethylentetramin als Ligand, V II [1] Kristallstrukturen des Zinkchlorid-Adduktes ZnCl2 • C6H12N4 und des Zinkbromid-Adduktes ZnBr2-C6H12N4 / Metal Complexes with Hexamethylenetetramine as a Ligand, V II [1] Crystal Structures of the Zinc Chloride Adduct ZnCl2 • C6H12N4, and the Zinc Bromide Adduct ZnBr2 • C6H12N4
Authors: Pickardt Joachim , Droas Pamela
Published: March 2015

By reaction of zinc chloride and zinc bromide with hexamethylenetetramine in water/methanol crystals of the adducts ZnCl2 • C6H12N4 and ZnBr2 • C6H12N4, resp. were obtained. The compounds are isotypic, they crystallize in the orthorhombic space group P21am (non-standard setting of space group Pmc21, No. 26), Z = 2. The lattice parameters of the zinc chloride adduct are a = 1168.0(4), b = 685.7(4), and c = 601.1(4) pm, of the zinc bromide adduct a - 1188.9(6), b = 721.5(5), and c = 602.3(4) pm. The adducts are polymeric, they form parallel chains in the crystal. The zinc atoms are bonded to two halogen atoms and, via nitrogen atoms, to two hexamethylenetetramine molecules, which act as bidentate ligands. The coordination of the zinc atoms is approximately tetrahedral
Molecular mechanisms of congenital hyperinsulinism
Authors: Rahman Sofia A , Nessa Azizun , Hussain Khalid
Published: March 2015

Congenital hyperinsulinism (CHI) is a complex heterogeneous condition in which insulin secretion from pancreatic β-cells is unregulated and inappropriate for the level of blood glucose. The inappropriate insulin secretion drives glucose into the insulin-sensitive tissues, such as the muscle, liver and adipose tissue, leading to severe hyperinsulinaemic hypoglycaemia (HH). At a molecular level, genetic abnormalities in nine different genes (ABCC8,KCNJ11,GLUD1,GCK,HNF4A,HNF1A,SLC16A1,UCP2andHADH) have been identified which cause CHI. Autosomal recessive and dominant mutations inABCC8/KCNJ11are the commonest cause of medically unresponsive CHI. Mutations inGLUD1andHADHlead to leucine-induced HH, and these two genes encode the key enzymes glutamate dehydrogenase and short chain 3-hydroxyacyl-CoA dehydrogenase which play a key role in amino acid and fatty acid regulation of insulin secretion respectively. Genetic abnormalities inHNF4AandHNF1Alead to a dual phenotype of HH in the newborn period and maturity onset-diabetes later in life. This state of the art review provides an update on the molecular basis of CHI.
Effects of the mycotoxin deoxynivalenol on steroidogenesis and apoptosis in granulosa cells
Authors: Guerrero-Netro Hilda M , Chorfi Younès , Price Christopher A
Published: March 2015

Mycotoxins can reduce fertility and development in livestock, notably in pigs and poultry, although the effect of most mycotoxins on reproductive function in cattle has not been established. One major mycotoxin, deoxynivalenol (DON), not only targets immune cells and activates the ribotoxic stress response (RSR) involving MAPK activation, but also inhibits oocyte maturation in pigs. In this study, we determined the effect of DON on bovine granulosa cell function using a serum-free culture system. Addition of DON inhibited estradiol and progesterone secretion, and reduced levels of mRNA encoding estrogenic (CYP19A1) but not progestogenic (CYP11A1 and STAR) proteins. Cell apoptosis was increased by DON, which also increased FASLG mRNA levels. The mechanism of action of DON was assessed by western blotting and PCR experiments. Addition of DON rapidly and transiently increased phosphorylation of MAPK3/1, and resulted in a more prolonged phosphorylation of MAPK14 (p38) and MAPK8 (JNK). Activation of these pathways by DON resulted in time- and dose-dependent increases in abundance of mRNA encoding the transcription factors FOS, FOSL1, EGR1, and EGR3. We conclude that DON is deleterious to granulosa cell function and acts through a RSR pathway.
Sonochemical synthesis of reactive boron nanomaterials and their combustion properties
Authors: Purdy Andrew P. , Epshteyn Albert , Weismiller Michael
Published: March 2015

We have demonstrated the synthesis of highly reactive boron nanomaterials by alkali metal reduction of BCl3 under sonication, followed by annealing. Unlike ordinary boron powders, these materials combust completely and release close to their theoretical energy content (based on elemental analysis) in polymer protected bomb calorimetry experiments. We have scaled up the synthesis using a commercial (Columbia International CIT-UHiPR-U1000V600) ultrasonic hi-pressure reactor. The synthesis reactions exhibit a scale problem, where they yield diminishes considerably on scale up, probably a result of alkali metals becoming trapped inside a mass of salts and rendered unable to react. We measured the combustion properties of the materials by bomb calorimetry, and thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), and report elemental analyses on selected samples.
Sorption recovery of platinum (II, IV) in presence of copper (II) and zinc (II) from chloride solutions
Authors: Kononova Olga , Karplyakova Nataliya , Duba Evgeniya
Published: March 2015

The sorption preconcentration of platinum (II, IV) ions was investigated in
presence of accompanying copper (II) and zinc (II) ions from chloride
solutions on the new ion exchangers CYBBER (Russia), previously unexplored.
The initial concentrations of platinum and accompanying ions were 0.25 mmol
L-1 and 2.0 mmol L-1, respectively, and the acidity of medium was 0.001 - 4.0
mol L-1. It was shown that the resins investigated - strong and weak basic
anion exchangers as well as chelate ion exchangers - possess good sorption
and kinetic properties. The simultaneous sorption of investigated ions
results in the complete recovery of platinum, while the non-ferrous metal
ions are sorbed at less than 20%. Followed by the selective elution of
platinum by thiourea (80 g L-1) solution in 0.3 M H2SO4, the quantitative
isolation of platinum was achieved (more than 90%). Therefore, the studied
ion exchangers can be recommended for recovery and separation of Pt(II,IV),
Cu(II) and Zn(II) ions.
Light in Medicine: The Interplay of Chemistry and Light
Authors: Allardyce Claire S. , Bays Roland , Thévenaz Nicolas
Published: March 2015

Photodynamic therapy (PDT) has had mixed reception in the clinic, with most success stories being based on the ablative capacity of PDT. In these applications, maximal combinations of light and an exogenous photosensitiser are used to generate high levels of reactive oxygen species
(ROS) that induce cell death either directly via necrosis or indirectly via vascular damage. However, recent advances in understanding the complex role of ROS in cell signalling have revealed potential new applications for PDT. For example, the proliferative effects of low level ROS could
be applied to wound healing or immunomodulation. These effects should also be considered in the ablative applications. With the decades of chemical advances for ablative PDT at hand – including targeting mechanisms to diseased cells and subcellular locations, optimisation of light absorption,
and carrier mechanisms that modulate the therapeutic response – the application of PDT to other types of treatment could be relatively rapid. This review serves to summarise some of these developments and suggest future directions.
Fe vs. TiO2 Photo-assisted Processes for Enhancing the Solar Inactivation of Bacteria in Water
Authors: Pulgarin César
Published: March 2015

Batch solar water disinfection (SODIS) is a known, simple and low-cost water treatment technology. SODIS is based on the synergistic action of temperature increase and light-assisted generation of Reactive Oxygen Species (ROS) on bacteria. ROS are generated via the action of solar photons
on i) Natural Organic Matter (NOM), ii) some mineral components of water (Fe oxides or Fe-organic complexes, nitrogen compounds) and iii) endogenous bacteria photosensitizers (e.g. cytochrome). SODIS has proven its effectiveness for remote settlements or urban slums in regions with
high incident solar radiation. All of the internal and external simultaneous processes are often driven by photoactive Fe-species present in the cell, as well as in the natural water sources. In SODIS, a temperature of 50 °C is required and due to this temperature dependence, only 1–2
L can be treated at a time. As required exposure time strongly depends on irradiation intensity and temperature, some SODIS households could be overburdened, leading to inadequate treatment and probable bacterial re-growth. This is why TiO2 photocatalysis and Fe photo-assisted systems
(i.e. photo-Fenton reactants) have been considered to enhance the photo-catalytic processes already present in natural water sources when exposed to solar light. Both TiO2 and Fe-photoassisted processes, when applied to water disinfection aim to improve the performance of
solar bacteria inactivation systems by i) enhancing ROS production, ii) making the process independent from the rise in temperature and as a consequence iii) allowing the treatment of larger volumes than 1–2 L of water and iv) prevent bacterial (re)growth, sometimes observed after sole solar treatment.
Transit Signal Priority with Connected Vehicle Technology
Authors: Hu Jia , Park Byungkyu (Brian) , Parkany A. Emily
Published: March 2015

Transit signal priority (TSP) has been studied as a control strategy that offers preference to transit vehicles at signalized intersections. Although TSP has been deployed in many places, several shortcomings, such as adverse effect on side streets and uncertainty about the benefit, have been identified. Therefore, a new TSP logic proposed to overcome these shortcomings takes advantage of the resources provided by connected vehicle technology, including two-way communications between buses and the traffic signal controller, accurate bus location detection and prediction, and number of passengers. The key feature of the proposed TSP logic is green time reallocation, which moves green time instead of adding extra green time. TSP is also designed to be conditional. That is, delay per person is used as the most important criterion in deciding whether TSP is to be granted. The logic developed in this research was evaluated in two ways: with analytical and microscopic simulation approaches. In each evaluation, the proposed TSP was compared with two scenarios: no TSP and conventional TSP. The analysis used bus delay and per person delay of all travelers as measures of effectiveness. The simulation-based evaluation results showed that the proposed TSP logic reduced bus delay between 9% and 84% compared with conventional TSP and between 36% and 88% compared with the no-TSP condition. The range of improvement corresponding to four volume-to-capacity ratios was tested. No significant negative effects were caused by the proposed TSP logic.
Factors Contributing to Bus Lane Obstruction and Usage in New York City
Authors: Safran Jeremy S. , Beaton Eric B. , Thompson Robert
Published: March 2015

This study quantitatively compared the effectiveness of bus lane designs across a variety of traffic environments in New York City. The study addressed the question of whether the recent movement away from curbside lane configurations and white-marked lanes toward offset lane configurations and red-painted lanes is justified by the impacts on bus lane obstruction and usage. Because the traffic environment can heavily impact bus lane effectiveness, the exploration of the effects of design on obstruction and usage required wide sampling and regression modeling. In all, 61 bus lane segments were sampled to allow for isolation and testing of the significance of individual effects. The results of the obstruction model demonstrated the influence of environmental variables, with pedestrian volume and taxi presence significantly impacting obstruction rates. Curbside lanes were 1.39 times more likely to be obstructed than offset lanes (p < .05), and the color of the markings showed no significant impact. The results of the usage model were also influenced by the environment, with obstruction, vehicular volume, and bus type all significantly impacting usage rates. Offset lanes were 1.97 times more likely to be used than curbside lanes, and red-painted lanes were 1.52 times more likely to be used than white-marked lanes (p < .005). Although city agencies cannot completely control the environmental factors affecting bus lane effectiveness, the evidence presented here, that offset lane configurations and red markings increase bus lane effectiveness, helps to justify current design philosophies and guide future design choices.
Dynamic Signal Priority Control Strategy to Mitigate Off-Ramp Queue Spillback to Freeway Mainline Segment
Authors: Yang Xianfeng , Lu Yang (Carl) , Chang Gang-Len
Published: March 2015

Congestion downstream of a freeway off-ramp often produces a traffic queue at the mainline and thus reduces the freeway capacity at the interchange area. To prevent such queue spillback, a proposed real-time control strategy provides a priority signal control to the off-ramp traffic when potential queue spillback is detected. Two priority strategies—unconditional and conditional controls—that quickly discharge the queuing vehicles on the off-ramp can contend with different congestion patterns at the freeway and local arterial. Based on field data from a freeway interchange in Zhubei, Taiwan, extensive simulation experiments demonstrate the effectiveness of the proposed strategies in preventing off-ramp queue spillbacks. The results show that the overall network performance can be significantly improved with the proposed strategy, even though some roadway segments of the local arterial network may experience negative impacts.
Influence of Air Void Content on Moisture Damage Susceptibility of Asphalt Mixtures
Authors: Varveri A. , Avgerinopoulos S. , Kasbergen C. , Scarpas A. , Collop A.
Published: March 2015

Because of the difficulties associated with the generation of finite element meshes based on X-ray computed tomography scans and with the extraordinary computational demands in performing three-dimensional (3-D) finite element analyses, past modeling efforts have focused primarily on two-dimensional representations of asphalt mixtures and have placed no emphasis on the inclusion of the air voids network in the body of an asphalt concrete specimen. A 3-D micromechanical moisture damage model has been developed and implemented in the finite element system CAPA-3D capable of addressing individually the three main phases of asphalt concrete: aggregate, mastic, and air voids. The 3-D finite element meshes of different types of asphalt mixtures were generated on the basis of X-ray scans. By means of CAPA-3D, the significance of the air voids structure in the development of moisture damage in asphalt concrete specimens was demonstrated. Availability of the model enables evaluation and ranking of the contribution of the characteristics of the individual mixture components to the overall mixture moisture resistance.
Toward Development of Asphaltic Materials to Resist Studded Tire Wear
Authors: Wen Haifang , Bhusal Sushanta
Published: March 2015

Studded tires are commonly used in parts of the United States to reduce snow- and ice-related accidents, but these tires can cause significant damage to the pavement because such wear in the wheel path leads to rutting in the asphalt concrete. Once studded tire wear is generated, there is no effective measure at present to repair the wear. Therefore, the reduction of studded tire wear is urgently needed to improve asphalt pavement conditions and save repair costs. This study quantifies the wear resistance potential of asphalt mixes by varying parameters such as aggregate type, gradation, asphalt type, air void content, and aggregate size to identify the most effective mixes for resisting studded tire wear. This work uses the studded tire wear simulator developed at Washington State University. In addition, the rutting and cracking performance of these test mixes is examined to identify the optimal mix design. The overall performance of the mixes is assessed to determine the optimal mix design variables, such as gradation, grade of asphalt binder, nominal maximum aggregate size, quality of aggregate, and air void content. Recommendations for additional research also are provided.
Enhanced Gradation Guidelines to Improve Asphalt Mixture Performance
Authors: Greene James , Chun Sanghyun , Choubane Bouzid
Published: March 2015

In 2010 a theoretical approach to the evaluation and specification of aggregate gradations to resist rutting was evaluated by the Florida Department of Transportation by accelerated pavement testing. This approach, known as the dominant aggregate size range (DASR) gradation model, provides a framework to ensure that the coarse aggregate of the resulting mixture has sufficient aggregate interlock to resist permanent deformation. Further research by the University of Florida and the Department of Transportation found that the properties of the interstitial components (ICs) within the DASR voids were strongly related to the durability and fracture resistance of asphalt mixtures. Parameters that made up the combined DASR-IC model included the DASR porosity, disruption factor (DF), effective film thickness (EFT), and fine aggregate ratio (FAR). The original evaluation of the DASR model was recently extended to include DASR gradations that might have had marginal aggregate interlock (i.e., marginal DASR porosity) and the effect of IC properties on mixture fracture resistance. The results confirmed that the rutting performance of the asphalt mixture was primarily controlled by the DASR porosity and that mixtures with marginal DASR porosity might still have had significantly better rutting performance than mixtures with poor DASR porosity. In addition, it was shown that the DASR porosity, DF, EFT, and FAR parameters played a critical role in mixture cracking performance. The validation of the combined DASR–IC model was documented, and the acceptable range of each parameter for improved mixture rutting and cracking performance was confirmed.
Active Crack Control for Continuously Reinforced Concrete Pavements in Belgium through Partial Surface Notches
Authors: Ren Dongya , Houben Lambert , Rens Luc , Beeldens Anne
Published: March 2015

Recent field observations on several newly constructed continuously reinforced concrete pavements (CRCPs) in Belgium indicate that the crack pattern is characterized by low mean crack spacing (approximately 1.0 m after 2 years in service) along with a high percentage of clusters of closely spaced cracks. Field surveys also indicate that it is difficult to reduce significantly the probability of a nonuniform crack pattern–-such as closely spaced cracks, meandering, and Y-cracks–-by slightly adjusting the amount of longitudinal steel. The nonuniform crack pattern is inevitable and common in conventional CRCP. Previous experience in the United States shows that active crack control for CRCP can eliminate the cluster cracks and that a more uniform crack pattern with straight cracks can be achieved. A new partial surface notch for active crack control was proposed and adopted first in the reconstruction project of Motorway E313 in Herentals, Belgium, in 2012. The introduction of the proposed active crack control method is described in detail. The effectiveness of improving the crack pattern is demonstrated in the field investigations.
Reliability-Based Mechanistic–Empirical Flexible Pavement Design
Authors: Hu Sheng , Zhou Fujie , Scullion Tom , Leidy Joe
Published: March 2015

It is well known that pavement design and construction involve many uncertainties and variations from specified design parameters. To address this issue, a reliability concept is often incorporated into the pavement design and analysis process. However, because of the complexity of modern mechanistic–empirical approaches, most of the existing reliability analyses deal only with some overall variability. A genuine reliability analysis considering the variability of specific input parameters is often computationally prohibitive. After a review of reliability approaches used in existing pavement design systems, Rosenblueth's 2 n 1 1 method is recommended as a good candidate for modern mechanistic–empirical pavement designs. Implementation of Rosenblueth's 2 n 1 1 method in the Texas Mechanistic–Empirical Flexible Pavement Design and Analysis System shows the simplicity and practicality of this approach. A pilot comparison demonstrates that this approach can make rational predictions considering the variability of different combinations of input parameters.
Pavement-Dependent Load Limits
Authors: Wang Hao , Al-Qadi Imad L. , Huft David L.
Published: March 2015

South Dakota statutes limit the weight of nonsteering axles to 500 lb/in. of tire width. The load allowance for single axles or spread tandem axles with wide-base tires is less than the axle load limit for dual tires. The objective of this research is to assess the potential impact of policy change if the load limit on wide-base tires is increased to be the same as the load limit on dual tires. First, a comprehensive literature review was conducted. Results indicated that the impact of wide-base tires on pavement damage varied, depending on pavement structure and damage mechanism. Pavement response and performance data were obtained from previous studies to calculate damage ratios between wide-base tires and dual tires with the same load. Different pavement failure mechanisms (fatigue cracking, top-down cracking, primary rutting, and subgrade rutting) were applied. Cost functions were then developed by relating the life-cycle cost of four typical asphalt pavement structures used in South Dakota to design traffic levels. The impact of the policy change on the cost of pavement damage was estimated by using detailed traffic data for each road segment in the state highway network. It was found that the cost of pavement damage increased because of wide-base tires on thin asphalt pavements commonly used in secondary roads. However, the impact of wide-base tires on Interstate highways was minimal. In addition, the environmental benefits brought about by the use of wide-base tires were equally significant, especially when the reduction in fuel consumption and air pollution was considered.
Asphalt Pavements with High Reclaimed Asphalt Pavement Content
Authors: Aurangzeb Qazi , Al-Qadi Imad L.
Published: March 2015

Today's sustainability-driven systems require a product or process to be environmentally beneficial as well as cost-effective. This study used life-cycle cost analysis (LCCA) and life-cycle assessment (LCA) to consider the economic and environmental feasibility of using a high content of reclaimed asphalt pavement (RAP) in asphalt mixtures. The LCCA conducted in the study incorporated agency cost as well as the costs incurred by the user in the construction work zone. Initial construction as well as future maintenance and rehabilitation activities were considered in the analysis. The hybrid LCA took into account the material, construction, and maintenance and rehabilitation phases of the pavement life cycle. The results showed savings in terms of costs and energy use and reduction in greenhouse gas emissions with an increase in RAP content. On the basis of the LCCA and LCA performed under various performance scenarios, break-even performance levels were identified for mixtures with up to 50% RAP content. Break-even performance levels underscored the importance of achieving field performance for recycled mixtures equivalent to that for control virgin mixtures.
An idealized wave–ice interaction model without subgrid spatial or temporal discretizations
Authors: Bennetts Luke G. , O’Farrell Siobhan , Uotila Petteri , Squire Vernon A.
Published: March 2015

A new numerical implementation is proposed for a wave-ice interaction model. It is applied to an idealized transect geometry. Wave attenuation due to ice floes and wave-induced ice fracture are both included in the model. The new method alleviates the need for subgrid spatial or temporal discretizations, thereby facilitating future integration of wave-ice interactions into large-scale coupled models.
What Can a Body Do? Answers from Trablus, Cairo, Beirut and Algiers
Authors: Marks Laura U.
Published: March 2015

The essay examines contemporary Arab films that express the body's forces. One strategy, common with other world cinemas, is that films carry out different operations at the molar and molecular levels, which correspond to different levels of embodiment and body politics. Another, more unique to Arab cinema, is to cultivate strategies of protecting and enfolding bodies, similar to what Foucault termed ars erotica. Third, they enlist the audience in a struggle to attain what Spinoza called ‘adequate ideas’, ideas that arise immanently from the body's capacities.
In Situ EPR Studies of Reaction Pathways in Titania Photocatalyst-Promoted Alkylation of Alkenes
Authors: Rhydderch Shona , Howe Russell
Published: March 2015

In situ EPR spectroscopy at cryogenic temperatures has been used to observe and identify paramagnetic species produced when titania is irradiated in the presence of reactants used in the photocatalytic alkylation of maleimide with t-butyl carboxylic acid or phenoxyacetic acid. It is shown that maleimide acts as an acceptor of conduction band electrons. Valence band holes oxidise t-butyl carboxylic acid to the t-butyl radical and phenoxyacetic acid to the phenoxyacetic acid radical cation. In the presence of maleimide, the phenoxymethyl radical is formed from phenoxyacetic acid. The relevance of these observations to the mechanisms of titania photocatalyst-promoted alkylation of alkenes is discussed.