bluuebunny/crossref_metadata_2025 huggingface dataset:
Darstellung und Reaktionen von zweikernigen Platin(II)-Komplexen; Einkristall-Röntgenstrukturanalyse eines Tetrakis(difluorphosphonato)-Palladat(II)-Komplexes / Preparation and Reactions of Binuclear Platinum(II) Complexes. Single Crystal X-Ray Diffraction Study of a Tetrakis(difluorophosphonato)palladate(II) Complex
Authors: Plinta Hans-Jürgen , Gereke Robert , Fischer Axel , Jones Peter G. , Schmutzler Reinhard
Published: March 2015

o-Methylbenzyldifluorophosphite 2 was obtained by the reaction of o-methylbenzyltrimethyl silyl ether 1 with chlorodifluorophosphine PF2Cl. The reaction of 2 with the palladium(II) complex 3 led to the tetrakis(difluorophosphonato)palladate(II) complex 7. The X-ray structure analysis of 7 confirmed the nearly exact square planar structure at the metal atom of the tetrakis(difluorophosphonato)palladate(II) dianion. Minimal deviations from the ideal geometry at palladium and phosphorus are mainly the result of thermal motion or disorder phenomena in the crystal. In the reaction of the platinum(II) complex 8 with chlorodifluorophosphine the binuclear tetrakis(chlorodifluorophosphine)platinum(II)chloro complex 9 was obtained. In acetonitrile, 9 was cleaved to form the mononuclear complex 10. Similar results were obtained in the oxidative addition reactions of the platinum(0) complex 11 with sulfuryl chloride fluoride, 12, sulfuryl fluoride, 13, and phosphorus pentafluoride. Tetrakis-(triphenylphosphine)-μ-dichlorodiplatinum(II) hexafluorophosphate 14 was isolated. In acetonitrile the mononuclear acetonitrile-bis(triphenylphosphine)chloroplatinum(II) hexafluorophosphate complex 15 was isolated.
Coordination and Reactions of Diazenes in Trimethylphosphinecobalt(I). Complexes - Syntheses and Structures of Complexes Containing μ2-(N,N′)-Benzo[c]cinnoline and η2-Azobenzene Ligands
Authors: Klein Hans-Friedrich , Helwig Michael , Koch Udo , Flörke Ulrich , Haupt Hans-Jürgen
Published: March 2015

Mononuclear compounds CpCo(η2-azobenzene)(PMe3) (1) or ortho-metallated

(2) are obtained from azobenzene and CpCo(PMe3)2 or CoMe(PMe3)4, respectively. With 4-acetoxo-azobenzene the ortho-metallation reaction gives isomers

, (3A) and

(3B) in a 1:1 ratio. Carbonylation of 2 gives

(4). Benzo[c]cinnoline affords CoCH3(η2-C12H8N2)(PMe3)3 (5) and μ2-(N ,N′)-C12H8N2(CoCp)[CoCp(PMe3)] (6). The coordination mode of the diazene ligands in 1 and 6 has been shown by X-ray crystal structure determinations. Dynamic N M R spectroscopy indicates intramolecular hopping of trimethylphosphine across the CoCo bond in 6.
TaFe1.14Te3, A New Low-Dimensional Ternary Tantalum Telluride
Authors: Neuhausen Jörg , Potthoff Elisabeth , Tremel Wolfgang , Ensling Jürgen , Gütlich Philipp , Kremer Reinhard K.
Published: March 2015

TaFe1.14Te3 is obtained from the elements in sealed quartz ampoules at 600°C. It crystallizes in the monoclinic space group P21/m with a = 7.4262(8), b = 3.6374(5), c = 9.9925(5) Å, and β = 109.166(8)°. The structure is built up from TaFeTe3 layers. Fe atoms with fractional occupancy are situated at the Te surfaces of the TaFeTe3 slabs giving rise to a 3 D connectivity of the TaFeTe3 layers in space. TaFe1.14Te3 exhibits metallic properties and shows an antiferromagnetic ordering at 215 K. Tight-binding band structure calculations show that Fe–Fe and Ta–Fe interactions are important for the electronic stability of TaFe1.14Te3; replacing Fe by more electron-rich transition metals such as Co or Ni may lead to compounds of composition TaM2Te3. A possible structure is derived from that of TaFe1.14Te3 by filling tetrahedral voids within the TaMTe3 layers with additional 3d metal atoms.
Zur Chemie der 1,3,5-Triaza-2-phosphinan-4,6-dione, Teil IV. / Chemistry of the 1,3,5-Triaza-2-phosphinane-4,6-diones, Part IV.
Authors: Farkens Michael , Neda Ion , Fischer Axel , Jones Peter G. , Schmutzler Reinhard
Published: March 2015

The 1,3,5-trimethyl-1,3,5-triaza-2-oxo-2λ4-phosphinane-4,6-diones 7 and 8 were obtained from the 6,8,10-trimethyl-2,2,3,3-tetrakis(trifluoromethyl)-6,8,10-triaza-1,4-dioxa-5 λ5-phosphaspiro[4.5]decane-7,9-diones 3 and 5, either by reaction with water or on heating; in the latter case we assume that tetrakis(trifluoromethyl)oxirane was eliminated. The hydrolysis of 2-(β-chloroethyl)amino-1,3,5-trimethyl-1,3,5-triaza-2-[p-nitrobenzoylimido]-2A4-phosphinane-4,6-dione 4 and of 5-bis-(β-chloroethyl)-amino-6,8,10-trimethyl-2,3-perchlorobenzo-6,8,10-triaza-1,4-dioxa-5λ5-phosphaspiro[4.5]decane-7,9-dione 6, in the same manner, gave the products 7 and 8. The synthesis of the perfluoropinacolyl spirophosphorane 3 is described. The compounds 3,7 and 8 were characterized from their 1H, 13C and 31P NMR spectra, mass spectra and through the X-ray structure determination of 8, in which the ring displays a flattened envelope conformation.
cis-1,2-Bis(diphenylphosphino)ethen-Nickel(0)-Komplexe / cis-1,2-Bis(diphenylphosphino)ethene Nickel(0) Complexes
Authors: Proft Bernd , Pörschke Klaus-Richard
Published: March 2015

We have studied the ligand properties of cis-Ph2PCH=CHPPh2 at nickel(0). Several homoleptic nickel(0) alkene complexes react with the twofold molecular quantity of cis-Ph2PCH=CHPPh2 to afford the red crystalline homoleptic 1:2 complex Ni(cis-Ph2PCH=CHPPh2)2 (1). The reactions of Ni(cdt) or Ni(C2H4)3 with equimolar amounts of cis-Ph2PCH=CHPPh2 yield orange-yellow crystals of the homoleptic 1:1 complex {(μ-cis-Ph2PCH=CHPPh2)Ni}n (2). Sparingly soluble 2 is presumably oligomeric with the (PCH=CHP)Ni moiety π-bonded to another nickel(0) center. The π bridges are rather stable and are only cleaved by strong π acceptors. For example, 2 reacts with CO to yield the known carbonyl complex (cis-Ph2PCH=CHPPh2)Ni(CO)2 (3). In contrast to the above synthesis of 2, the 1:1 reaction of Ni(cod)2 with cis-Ph2PCH=CHPPh2 affords orange-red crystals of the alkene complex (cis-Ph2PCH = CHPPh2)Ni(cod) - THF (4) in moderate yield. Ni(1,5-hexadiene)2 reacts readily with cis-Ph2PCH=CHPPh2 (1:1) to give yellow (cis-Ph2PCH=CHPPh2)Ni(rac-η2,η2-C6H10) (5, 77%), which exhibits a fluxional diene coordination. That these thermally labile alkene complexes are formed at all, is ascribed to the chelate effect of the dienes. From the reaction of 2, 4 or 5 with ethyne, yellow microcrystals of (cis-Ph2PCH = CHPPh2)Ni(C2H2) · Et2O (6) are obtained.
Notizen: Ba2[TaN3] und Sr2[TaN3]: Isotype Nitridotantalate(V) mit Tetraederketten ∞
1[TaN2N2/2
4-] / Ba2[TaN3] and Sr2[TaN3]: Isotypic Nitridotantalates(V) with Tetrahedral Chains ∞
1[TaN2N2/2
4-]
Authors: Helmlinger Falko K.-J. , Höhn Peter , Kniep Rüdiger
Published: March 2015

Single crystals of Ba2[TaN3] (monocl., C2/c (Nr. 15); a = 613.0(3), b = 1181.5(4), c = 1326.3(5) pm; β = 91.1(1)°; Ζ = 8) were prepared from mixtures of Li and Ba (molar ratio 1:1) in tantalum crucibles and by reaction with nitrogen (1 atm) at 1000°C. The crystal structure (an isotype of Ba2[ZnO3]) contains infinite tetrahedral anions ∞
1[TaN2N2/2
4-] (Ta–N: 192.2(13)– 198.8(9) pm) which can be described as “Zweier-Einfach-Kette”. Sr2[TaN3] (monocl., C2/c (Nr. 15); a = 600.5(3), b = 1131.3(7), c = 1260.3(7) pm; β = 91.71(6)°; Ζ = 8) was obtained as a yellow powder containing excess Sr2N by reaction of Sr2N and Ta (molar ratio Sr: Ta = 4.5:1) with nitrogen (1 atm) at 1000°C. The isotypic relationship to Ba2[TaN3] was confirmed by X-ray powder investigations.
Notizen: Die Kristallstruktur des Rhenium-Tolankomplexes [ReCl4(PhC ≡ CPhXOPCl3)] / The Crystal Structure of the Rhenium-tolane Complex [ReCl4(PhC ≡ CPh)(OPCl3)]
Authors: Frenzen Gerlinde , Gudenberg Dorothea Wolff von , Dehnicke Kurt
Published: March 2015

The crystal structure of [ReCl4(PhC = CPh)(OPCl3)] was solved with X-ray methods. Space group P1̄, Z = 2, 2085 observed unique reflections, R = 0.029. Lattice dimensions at -70°C: a = 857.0(2), b = 937.9(2), c = 1249.6(2) pm, α = 87.43(3)°, β = 83.48(3)°, γ = 89.80(3)°. [ReCl4(PhC ≡ CPh)(OPCl3)] has a molecular structure with the alkyne ligand bonded side-on (bond lengths Re-C 198.9(8) and 198.6(7) pm). The oxygen atom of the solvating POCl3 molecule is coordinated in trans position to the ReC2 unit of the alkyne ligand (bond length Re-O 226.7(5) pm).
Constituents of Euphorbiaceae, 10. Comm. / New Cerebrosides from Euphorbia characias L.
Authors: Falsone G. , Cateni F. , Katusian F. , Wagner H. , Seligmann O. , Pellizer G. , Asaro F.
Published: March 2015

Four new cerebrosides C-1 – C-4 were isolated from the latex of Euphorbia characias L. On the basis of spectral evidences and chemical reactions they were characterized as (2S, 3S, 4R, 5R, 6Z)-1-O-(β-D-glucopyranosyl)-2N-[(2'R)-2′-hydroxy-(15′Z)-tetracosenoyl]-6(Z)-octadecene-1,3,4,5-tetraol-2-amino (C-1), (2 S, 3 S, 4 R, 5 R, 6 Z)-1-O-(β-D-glucopyranosyl)-2N-[(2′ R)-2′hydroxy-(17′ Z)-hexacosenoyl]-6(Z)-octadecene-1,3,4,5-tetraol- 2-amino (C-2), (2S, 3S, 4R, 5R, 6Z)-1-O-(β-D-glucopyranosyl)-2N-[(2′R)-2′-hydroxy-(19′Z)-octacosenoyl]-6-(Z)-octadecene-1,3,4,5-tetraol-2-amino (C-3) and (2 S, 3 S, 4 R, 5 R, 6 Z)-1-O-(β-D-glucopyranosyl)-2N-[(2′R)-2′-hydroxy-octacosanoyl]-6-(Z)-octadecene-1,3,4,5-tetraol-2-amino (C-4).

Reversed phase column flash chromatography was effective for the isolation of the cerebrosides. FAB-MS spectrometry, 1H NMR, 13C NMR analysis and chemical reactions were useful in providing information for the structure elucidation.
On the Chromophore of the Ninhydrin-Amino Acid Color Reaction
Authors: Dietz F. , Rommel-Möhle K. , Schleitzer A. , Tyutyulkov N.
Published: March 2015

The long-wavelength absorption of the dye formed at the ninhydrin-amino acid color reaction is caused by the anion (enolate) of diketohydrindamine-diketohydrindylidene (Ruhemann’s purple). Using the results of quantum-chemical calculations (MNDO, PPP) the basic chromophoric system was identified as two coupled five-membered rings which have partial anti-aromatic character like the antiaromatic cyclopentadienyl cation.
Über die Umsetzung von Phosphorverbindungen mit dem Strukturelement P(:X)H (X = O, S) mit 1,3,5-Trimethylhexahydro-1,3,5-triazin. Darstellung und Reaktionen α-(N-Methylamino)methyl-substituierter Phosphorverbindungen / Reactions of Phosphorus Compounds Containing the P(:X)H Group (X = O, S) with 1,3,5-Trimethylhexahydro-1,3,5-triazine. Synthesis and Reactions of α-(N-Methylamino)methyl Substituted Phosphorus Compounds
Authors: Goerlich Jens R. , Neda Ion , Well Michael , Fischer Axel , Jones Peter G. , Schmutzler Reinhard
Published: March 2015

The reactions of the acids la-4a and 8a with 1,3,5-trimethylhexahydro-1,3,5-triazine furnished compounds 1b-4b and 8b. The IR investigation of 1 b, 4b and 8b revealed P=O ··· H—N interactions. In the unusual reaction of lb with methyl iodide the quaternary ammonium iodide [(H3C)2P(:O)CH2N(CH3)3]+I- 1c was formed. The reaction of 2b with methyl iodide produced the ammonium iodide [(H3C)2P(:S)CH2NH2CH3]+I- 2c. The structure of 2c was confirmed by X-ray crystal structure analysis, which showed the expected distorted tetrahedral geometry at phosphorus and revealed N—H ••• I hydrogen bonds. Reaction of 8b with methyl iodide led to the formation of the ammonium iodide 8c by methylation at the nitrogen atom. In the reaction of lb and 2b with HPF6 the compounds 1 d and 2d were obtained. The compounds 1 d and 2d, due to their instability at room temperature, could be identified only by 1H and 31P NMR spectroscopy.
Gläser und Verbindungen im System P4S4— As4S4— As4Se4 — P4Se4 / Glass and Compounds in the System P4S4—As4S4—As4Se4—P4Se4
Authors: Blachnik Roger , Lönnecke Peter , Nuß Jürgen
Published: March 2015

Glas forming regions and glass temperatures of the system P4S4–As4S4–As4Se4–P4Se4 have been determined by thermoanalytical and X-ray methods. In the whole system crystalline samples have been obtained by annealing. From the pure phases As4S4 and P4Se4 broad regions of solid solutions extend into the system. In the P4S4 corner the formation of A4B3 (A = P, As; B = S, Se) molecules is observed.

As with A4B3 molecules, a stepwise substitution of P by As atoms, and of S by Se atoms is possible. All molecules of the series P4_„As„S4 and As4S4_„Se„ (n = 0, 1, 2, 3, 4) were detected by 31P NMR and/or mass spectroscopy.
Sterisch belastete cyclische Phosphanborane / Sterically Crowded Cyclic Phosphine-Boranes
Authors: Müller Gerhard , Lachmann Joachim
Published: March 2015

The anionic phosphine o-(diphenylphosphinomethyl)phenyl L has been used to prepare the sterically crowded cyclic phosphine-boranes BL3, tBuBL2, and tBu2BL by reaction of the lithiated ligand LiL with B(OMe)3, tBuB(OMe)2, and tBu2BOMe, respectively. In the new compounds tBuBL2 and tBu2BL one ligand L is bonded to the boron center by both its carbanionic and its phosphino function with formation of five-membered rings. In solution 11B and 31P NMR spectroscopy does not indicate substantial B—P dissociation, i.e., the existence of threecoordinate boron. The steric bulk of L in BL3 leads to the formation of oligomers in solution, presumably by a bridging coordination mode of L to two boron centers. No conclusive evidence as to the monomeric or oligomeric nature of BL3 in the solid state can be given, however. Five-membered ring formation is proven for the solid state by X-ray structure determinations of tBuBL2 and tBu2BL which in addition confirm that the steric bulk of L is superior to that of a tert. butyl group.
Darstellung von quaternären Selenodiphosphaten(IV) aus Halogenidschmelzen: Die Kristallstruktur des CuAl[P2Se6] / Preparation of Quaternary Selenodiphosphates(IV) from Halide Melts: The Crystal Structure of CuAl[P2Se6]
Authors: Pfeiff Regine , Kniep Rüdiger
Published: March 2015

Quaternary hexaselenodiphosphates MIMIII[P2Se6] (MI/MIII = Cu/In, Cu/Cr, Ag/Αl, Ag/In, Ag/V, Ag/Cr) are obtained by reaction of the binary metal halides with Mg2[P2Se6] followed by cooling from the melt (Tmax = 530°C; cooling rate: 50°C/h):

M1 + MIIICl3 + Mg2[P2Se6]⃗⃗ ⃗→ MIMIII[P2Se6] + 2 MgCl2.

This method of preparation was also successfully used for the hitherto unknown quaternary hexaselenodiphosphate CuAl[P2Se6]. The crystal structure of CuAl[P2Se6] (trig. R 3 (No. 148); a = 627.95(2) pm; c = 1997.13(6) pm; Z = 3) is closely related to that of Fe2[P2Se6] (trig. R3). Selenium atoms are arranged in hexagonal close packed layers. CuI, AlIII and the P2 pairs occupy the octahedral sites of every second selenium double layer in such a way that the P2 pairs are surrounded by Cu1 and AlIII species (random distribution).
Zur Elektronenstruktur hochsymmetrischer Verbindungen der f-Elemente, XXV / The Electronic Structure of Highly Symmetrical Compounds of thef-Elements, XXV
Authors: Hagen Chrystel , Amberger Hanns-Dieter
Published: March 2015

A simple method is described which allows the growth of large transparent single crystals of tris[bis(trimethylsilyl)amido]lanthanide(III) complexes (lanthanide = Pr, Nd, Sm, Eu, Er, Tm, Yb). We have used these single crystals as starting material for a number of chemical reactions and detected no contamination with THF containing by-products. The superior quality of the crystals grown is demonstrated by optical polarization experiments. From the spectra a large negative crystal field parameter B2
0 could be concluded
Zur Silylierung bifunktioneller Amidine der Oxalsäure / On the Silylation of Bifunctional Amidines of Oxalic Acid
Authors: Beckert Rainer , Vorwerk Steffen , Lindauer Dirk , Döring Manfred
Published: March 2015

Ν,N′,N″,N‴-Tetraaryl-oxalic amidines react with N-trimethylsilyldiethylamine to yield the activated and open chained derivatives 3a, b. By the use of diorganyldichlorosilanes the new 1,3-diaza-2-sila-cyclopentanes 5a-d were obtained. Cycloacylations of 3a with geminal dichlorides are leading to different kinds of heterocyclic compounds
New Kaempferol Glycosides from Equisetum Species
Authors: Veit M. , Czygan F.-C. , Witte L. , Markham K. R. , Geiger H.
Published: March 2015

Kaempferol-3-O-rutinoside-7-O-sophoroside and kaempferol-3-O-(6-O-malonylgluco-side)-7-O-glucoside were isolated from Equisetum palustre and Equisetum x litorale, respectively. Their structures are prooved
Electronic Spectra and Photochemistry of Tin(II), Lead(II), Antimony(III), and Bismuth(III) Bromide Complexes in Solution
Authors: Oldenburg Karin , Vogler Arnd
Published: March 2015

The electronic spectra of bromo complexes of main group metal ions with an s2 electronic configuration (SnBr3
-, PbBr3
-, PbBr4
2-, SbBr4
-, SbBr6
3-, BiBr4
-, BiBr6
3-) in acetonitrile show long-wavelength absorption bands which are assigned to metal-centered sp transitions. Compared to the corresponding chloro complexes the sp bands of the bromo complexes appear at longer wavelength due to sp/LMCT mixing (LMCT = ligand-to-metal charge transfer). As a result of this mixing the luminescence which originates from low-energy sp excited states is much weaker than that of the chloro complexes. Moreover, some of the bromo complexes (e.g. BiBr4-) undergo a photochemical redox decomposition induced by LMCT excitation.
7Li Solid State NMR Study of a TMEDA Complex of Trimethylsilylcyclopentadienyllithium
Authors: Pietraß Tanja , Burkert Paul K.
Published: March 2015

7Li solid state NMR spectroscopy of Ν,Ν,N′,N′-tetramethylethylenediamine-trimethylsilylcyclopentadienyllithium yielded an unusually large quadrupole coupling constant, that decreases with increasing temperature (188-165 kHz in the temperature range 210-335 K). Structural features, known from the X-ray analysis, are compared with the NMR results.
Zur Struktur des Pentaazadienidions [tol-N=N-N-N=N-tol]-. Synthese und Kristallstruktur von Cs2(18-Krone-6)(tolN5tol)2 und (NH4)[Cr(NH3)6(H2O)4](tolN5tol)4 / The Structure of the Pentaazadienide Anion [tol-N=N—N—N=N-tol]-. Synthesis and Crystal Structure of Cs2(18-Crown-6)(tolN5tol)2 and (NH4)[Cr(NH3)6(H2O)4](tolN5tol)4
Authors: Dieterich Susanne , Strähle Joachim
Published: March 2015

A concentrated solution of CsCI, 18-crown-6, and tol-N=N—N(H)—N=N-tol in aqueous ammonia affords Cs2(18-crown-6)(tolN5tol)2, which crystallizes in the triclinic space group P1̄ with a = 852.6(2), b = 1139.4(3), c = 1373.9(4) pm, α = 104.17(3), ß = 95.94(2), γ = 110.74(2)°, Ζ = 1. In the structure centrosymmetrical [Cs2(18-crown-6)]2+ moieties are packed with pairs of 1,5-bis(tolyl)pentaazadienide anions to built up columns along [100]. The N—N distances N1 —N2 = 128 pm and N4—N5 = 129 pm in the pentaazadienide anions indicate localized double bonds, while the distances N2—N3 and N3—N4 of 134 pm can be assigned to single bonds. A mixture of Cr(NH3)6
3+ and tolNNN(H)NNtol in concentrated aqueous ammonia yields triclinic (NH4)[Cr(NH3)6(H2O)4](tolN5tol)4 crystallizing in the space group P l with the lattice parameters a = 1561.1(1), b = 1619.3(3), c = 1703.3(2) pm, α = 107.03(1), β = 116.81(1), γ = 101.75(1)°, Ζ = 2. The structure contains tolN5tol- anions, NH4
+ cations and [Cr(NH3)6(H2O)4]3+ complexes in which four triangular faces of the Cr(NH3)6 octahedron are capped by water molecules which are linked via hydrogen bonds. Within the pentaazadienide anions which are connected with the [Cr(NH3)6(H2O)4]3+ complexes also via hydrogen bonds an indication for localized double bonds Ν1=Ν2 and N4=N 5 has been obtained.
Tripodliganden mit drei verschiedenen Donorgruppen: Synthese und Koordination von CH3C(CH2PR2)(CH2PR′2)(CH2PR"2) / Tripod Ligands with Three Different Donor Groups: Synthesis and Coordination of CH3C(CH2PR2)(CH2PR′2)(CH2PR''2)
Authors: Heidel Horst , Huttner Gottfried , Helmchen Günter
Published: March 2015

Tripod ligands CH3C(CH2PR2)(CH2PR′2)(CH2PR″2), 6(a—e), with three different donor groups are obtained from CH3C(CH2Cl)(CH2Br)(CH2OSO2CF3), 3, by successive replacement of the three different leaving groups. 3 itself is easily accessible from CH3C(CH2OH)3 in a few simple steps. The general applicability of this strategy is demonstrated by the preparation of five different ligands 6(a—e). For one specific example (6 a) the coordination behaviour is examplified by the synthesis of its Mo(CO)3 derivative: CH3C(CH2P(Ph)2)(CH2P(3-Tol)2)(CH2P(4-Tol)2)• Mo(CO)3 (7). All compounds, including their intermediates CH3C(CH2Cl)(CH2Br)(CH2PR2), 4(a—c), and CH3C(CH2PR2)(CH2PR′2)(CH2C1), 5(a— c), have been obtained in an analytically pure state and fully characterized by their spectroscopic data. The methods developed lend themselves to the almost deliberate shaping of tripod metal templates.
Synthesis and Characterization of Tris(trimethyltin) Thiophosphate (Me3Sn)3PO3S
Authors: Shihada Abdel-Fattah
Published: March 2015

(Me3Sn)3PO3S has been prepared from the reaction of Me3SnCl with Na3PO3S • 12 H2O under cooling in aqueous medium. Its IR and Raman spectra are found to be consistent with a polymeric structure with tetra- and penta-coordinated tin atoms. The 31P NMR and mass spectra of (Me3Sn)3PO3S are reported and discussed.
Crystal Structure Investigation of Copper(II) Thiocyanato and Cobalt(III Azido Complexes of Picolinic Acid; [Cu(pic)(SCN)(H2O)2] · 2H2O and [Na2Co(pic)2(N3)2(H2O)6] [Co(pic)2(N3)2] · 2H2O
Authors: Goher Mohamed A. S. , Abu-Youssef Morsy A. M. , Mautner Franz A.
Published: March 2015

The structures of [Cu(pic)(NCS)(H2O)2] · 2H2O, complex 1, and

[Na2Co(pic)2(N3)2(H2O)6][Co(pic)2(N3)2] · 2H2O, complex 2, were determined by X-ray crystallography. Crystal data: 1, C7H12CuSN2O6, orthorhombic, space group Pbca, a = 8.749(4), b = 10.786(5), c = 26.882(9) Å, Z = 8, Rw =0.046 for 826 observed diffractometer data; 2, C24H32Co2Na2N16O16, triclinic, space group P1̄, a = 7.297(3), b = 8.806(4), c = 15.820(7) Å, a = 105.31(3), β = 95.09(3), γ = 99.86(3)°, Z = 1, and Rw = 0.064 for 1680 observed MoKa data.

Complex 1 features six-coordinated copper atoms, N,O-bidentate chelate picolinato anions, and μ(N,S) bridging thiocyanato groups with N at the basal site and S at the apical site of tetragonal bipyramid. The remaining two sites are occupied by aqua molecules, whereas two other water molecules serve as lattice water. The bridging thiocyanato groups link the copper polyhedra to form chains along the b axis of the unit cell. Complex 2 contains two Co(III) atoms located at different inversion centers. Co 1 in the [Na2Co(pic)2(N3)2(H2O)6]+ cation is six-coordinated by two trans picolinato anions (A) via their N 1 and O 1 atoms and by two terminal azido ligands. Two oxygen atoms (O 2 and O 2a) of two picolinate anions (A) act as μ(Ο,Ο) bridging atoms at basal sites to form a four-membered Na2O2 ring. Each sodium atom is further linked to three aqua ligands giving rise to trigonal-bipyramidal coordination environments. Two additional lattice water molecules are located between the dimeric sodium polyhedra. Co 2, in the [Co(pic)2(N3)2]- anion, is also six-coordinated by pairs of trans N,O-picolinate anions (B) and terminal azido groups.
Crystal and Molecular Structures of the Free Base and the Monohydrochloride Salt of the Antileukemic Agent Glyoxal bis(Amidinohydrazone) [`Glyoxal bis(Guanylhydrazone)’]
Authors: Mutikainen Ilpo , Elo Hannu , Tilus Pirkko
Published: March 2015

The first study on the crystal and molecular structures of basic forms of bis(amidinohydrazones) is reported. The structures of the free base and the monohydrochloride salt of the antileukemic agent glyoxal bis(amidinohydrazone) (GBG) were determined by single crystal X-ray diffraction and were refined to R-values of 0.038 and 0.040, respectively. These structures are of special interest because recent results indicate that, in contrast to previous assumptions, the free base may be the actual antileukemic form of bis(amidinohydrazones) and that the monocation form is the predominant species of antileukemic bis(amidinohydrazones) at physiological conditions. In the crystals of the free base as well as in those of the monohydrochloride salt, GBG was found to exist solely in the all-trans configuration of the chain and to consist of one of the three possible geometrical isomers only. In the solid state, GBG free base consists solely of the endiamine tautomer instead of the 'classical’ carboximidamide tautomer, as does also the non-protonated part of GBG monocation in the monohydrochloride salt. Proton NMR measurements indicated that the free base consists of the endiamine tautomer also in dimethyl sulfoxide solution. In the solid state, both of the compounds studied consist of stacks of planes. In the case of the free base, the stacks are crisscross to each other. The distance between the mean planes of the molecules or the monocations is approximately 3.5 Å. The crystals of the monohydrochloride salt contain one molecule of water per each GBG monocation. In both compounds studied, the molecules in the crystals are held together by very extensive hydrogen bond networks and by the interaction of delocalized π-electrons. The crystal of C4H10N8 is monoclinic, space group C2/c with a = 15.874(6), b = 6.972(4), c = 7.8l3(5)Å, β = 90.34(4)° and Z = 4. The crystal of C4H13N8OC1 is monoclinic, space group P21/n with α = 7.010(3), b = 22.307(9), c = 7.028(3)Å, β = 66.33(3)° and Ζ = 4.
Reliability Assessment of Structural Sealant Durability
Authors: Lee Sang Kook , Hirouki Miyauchi , Jeong Jin Young
Published: March 2015

Many questions have been raised on how we can practically measure and predict the durability and service life of structural silicone sealants. Meanwhile, facade engineers have many requirements for the reliability of structural silicone sealants. Thus, accelerated reliability engineering was employed in order to assess the durability of structural silicone sealants in terms of 30-year service life. Firstly, the environmental and application conditions of structural silicone sealants need to be defined. Some of the major factors that significantly influence the degradation of structural silicone sealant includes temperature change, movement of joints, stress induced by wind pressure, load stress on glass, humidity, solar UV radiation, etc. For this study, temperature, humidity, and the movement of joints were chosen as failure-causing factors since they are considered to the most predominant in structural silicone sealants. The stress level was selected to reflect extremely severe weathering conditions (ISO28278-1, Class T1, T2, T3). For the design of the accelerated life time test, stress levels of 2 as well as three stress factors were used. In our experiments, indoor accelerated weathering tests were performed to obtain coefficients such as an acceleration factor and shape parameter for service-life prediction. The results exhibited a strong linear regression to calculated fit based on statistical methods. Each factor was thus shown to correlate with others using the Mini-tab toolkit. The test results were also analyzed by the commercially available reliability software, ALTA 7, in which B10 life values were obtained with a 90 % confidence level and a 30-year service-life prediction. The failure-mode test lasted until the complete failure of structural silicone sealants. The failure mode was defined as a tensile strength value of 40 % the strength, which is widely used in many industry standards (500 kPa). Considering the relationship between the experimental parameters and the failure mode of the sealants, a higher chance of failure was observed with higher temperature, humidity, and greater joint movement. In particular, joint movement was found to be the most significant factor in causing failure.
Evaluation of Building Facade Component Staining by the Outdoor Exposure and the Indoor Accelerated Staining Tests of Sealed Joint
Authors: Miyauchi Hiroyuki , Kai Masanori , Ando Katsuhiro , Kim Young-Joo , Kusumi Akira
Published: March 2015

This study evaluated panel staining around sealed joints using outdoor-exposure and indoor-accelerated staining tests. The outdoor-exposure staining test was performed for one-component silicone sealant (SR-1) and one-component modified silicone sealant (MS-1) at exposure sites in South Korea, Japan, China, and Malaysia. The test specimens were T-shaped sealed joints with artificial marble substrates. The exposure time was four and eight months. In all exposure sites, stains were observed on the panel with the SR-1 sealant after a short time period, whereas MS-1 sealant showed good stain resistance. The indoor accelerated staining tests were performed for SR-1 and MS-1 sealed joints using four staining materials. After an accelerated staining test by the sunshine weather meter, panel staining was performed using three staining materials (the carbon black-dispersed aqueous paste) and a proposed volcanic ash staining material. When the staining water mixed with UNIRANT77 or the proposed powder of volcanic ash was used for the staining test, the stain on the panel joined by SR-1 was greater than that on the panel joined by MS-1.
What Elements of the Inflammatory System Are Necessary for EpileptogenesisIn Vitro?
Authors: Park Kyung-Il , Dzhala Volodymyr , Saponjian Yero , Staley Kevin J.
Published: March 2015

Epileptogenesisin vivocan be altered by manipulation of molecules such as cytokines and complement that subserve intercellular signaling in both the inflammatory and central nervous systems. Because of the dual roles of these signaling molecules, it has been difficult to precisely define the role of systemic inflammation in epileptogenesis. Organotypic hippocampal brain slices can be maintained in culture independently of the systemic inflammatory system, and the rapid course of epileptogenesis in these cultures supports the idea that inflammation is not necessary for epilepsy. However, this preparation still retains key cellular inflammatory mediators. Here, we found that rodent hippocampal organotypic slice cultures depleted of T lymphocytes and microglia developed epileptic activity at essentially the same rate and to similar degrees of severity as matched control slice cultures. These data support the idea that although the inflammatory system, neurons, and glia share key intercellular signaling molecules, neither systemic nor CNS-specific cellular elements of the immune and inflammatory systems are necessary components of epileptogenesis.
Spine Loss in Primary Somatosensory Cortex during Trace Eyeblink Conditioning
Authors: Joachimsthaler Bettina , Brugger Dominik , Skodras Angelos , Schwarz Cornelius
Published: March 2015

Classical conditioning that involves mnemonic processing, that is, a “trace” period between conditioned and unconditioned stimulus, requires awareness of the association to be formed and is considered a simple model paradigm for declarative learning. Barrel cortex, the whisker representation of primary somatosensory cortex, is required for the learning of a tactile variant of trace eyeblink conditioning (TTEBC) and undergoes distinct map plasticity during learning. To investigate the cellular mechanism underpinning TTEBC and concurrent map plasticity, we used two-photon imaging of dendritic spines in barrel cortex of awake mice while being conditioned. Monitoring layer 5 neurons' apical dendrites in layer 1, we show that one cellular expression of barrel cortex plasticity is a substantial spine count reduction of ∼15% of the dendritic spines present before learning. The number of eliminated spines and their time of elimination are tightly related to the learning success. Moreover, spine plasticity is highly specific for the principal barrel column receiving the main signals from the stimulated vibrissa. Spines located in other columns, even those directly adjacent to the principal column, are unaffected. Because layer 1 spines integrate signals from associative thalamocortical circuits, their column-specific elimination suggests that this spine plasticity may be the result of an association of top-down signals relevant for declarative learning and spatially precise ascending tactile signals.
Cortical Activity Predicts Which Older Adults Recognize Speech in Noise and When
Authors: Vaden Kenneth I. , Kuchinsky Stefanie E. , Ahlstrom Jayne B. , Dubno Judy R. , Eckert Mark A.
Published: March 2015

Speech recognition in noise can be challenging for older adults and elicits elevated activity throughout a cingulo-opercular network that is hypothesized to monitor and modify behaviors to optimize performance. A word recognition in noise experiment was used to test the hypothesis that cingulo-opercular engagement provides performance benefit for older adults. Healthy older adults (N= 31; 50–81 years of age; mean pure tone thresholds <32 dB HL from 0.25 to 8 kHz, best ear; species: human) performed word recognition in multitalker babble at 2 signal-to-noise ratios (SNR = +3 or +10 dB) during a sparse sampling fMRI experiment. Elevated cingulo-opercular activity was associated with an increased likelihood of correct recognition on the following trial independently of SNR and performance on the preceding trial. The cingulo-opercular effect increased for participants with the best overall performance. These effects were lower for older adults compared with a younger, normal-hearing adult sample (N= 18). Visual cortex activity also predicted trial-level recognition for the older adults, which resulted from discrete decreases in activity before errors and occurred for the oldest adults with the poorest recognition. Participants demonstrating larger visual cortex effects also had reduced fractional anisotropy in an anterior portion of the left inferior frontal-occipital fasciculus, which projects between frontal and occipital regions where activity predicted word recognition. Together, the results indicate that older adults experience performance benefit from elevated cingulo-opercular activity, but not to the same extent as younger adults, and that declines in attentional control can limit word recognition.
Reward-Dependent Modulation of Movement Variability
Authors: Pekny Sarah E. , Izawa Jun , Shadmehr Reza
Published: March 2015

Movement variability is often considered an unwanted byproduct of a noisy nervous system. However, variability can signal a form of implicit exploration, indicating that the nervous system is intentionally varying the motor commands in search of actions that yield the greatest success. Here, we investigated the role of the human basal ganglia in controlling reward-dependent motor variability as measured by trial-to-trial changes in performance during a reaching task. We designed an experiment in which the only performance feedback was success or failure and quantified how reach variability was modulated as a function of the probability of reward. In healthy controls, reach variability increased as the probability of reward decreased. Control of variability depended on the history of past rewards, with the largest trial-to-trial changes occurring immediately after an unrewarded trial. In contrast, in participants with Parkinson's disease, a known example of basal ganglia dysfunction, reward was a poor modulator of variability; that is, the patients showed an impaired ability to increase variability in response to decreases in the probability of reward. This was despite the fact that, after rewarded trials, reach variability in the patients was comparable to healthy controls. In summary, we found that movement variability is partially a form of exploration driven by the recent history of rewards. When the function of the human basal ganglia is compromised, the reward-dependent control of movement variability is impaired, particularly affecting the ability to increase variability after unsuccessful outcomes.
A Direct Descending Pathway Informing Locomotor Networks about Tactile Sensor Movement
Authors: Ache Jan M. , Haupt S. Shuichi , Dürr Volker
Published: March 2015

Much like visually impaired humans use a white-cane, nocturnal insects and mammals use antennae or whiskers for near-range orientation. Stick insects, for example, rely heavily on antennal tactile cues to find footholds and detect obstacles. Antennal contacts can even induce aimed reaching movements. Because tactile sensors are essentially one-dimensional, they must be moved to probe the surrounding space. Sensor movement is thus an essential cue for tactile sensing, which needs to be integrated by thoracic networks for generating appropriate adaptive leg movements. Based on single and double recordings, we describe a descending neural pathway comprising three identified ON- and OFF-type neurons that convey complementary, unambiguous, and short-latency information about antennal movement to thoracic networks in the stick insect. The neurons are sensitive to the velocity of antennal movements across the entire range covered by natural movements, regardless of movement direction and joint angle. Intriguingly, none of them originates from the brain. Instead, they descend from the gnathal ganglion and receive input from antennal mechanoreceptors in this lower region of the CNS. From there, they convey information about antennal movement to the thorax. One of the descending neurons, which is additionally sensitive to substrate vibration, feeds this information back to the brain via an ascending branch. We conclude that descending interneurons with complementary tuning characteristics, gains, input and output regions convey detailed information about antennal movement to thoracic networks. This pathway bypasses higher processing centers in the brain and thus constitutes a shortcut between tactile sensors on the head and the thorax.
Impaired Attention and Synaptic Senescence of the Prefrontal Cortex Involves Redox Regulation of NMDA Receptors
Authors: Guidi Michael , Kumar Ashok , Foster Thomas C.
Published: March 2015

Young (3–6 months) and middle-age (10–14 months) rats were trained on the five-choice serial reaction time task. Attention and executive function deficits were apparent in middle-age animals observed as a decrease in choice accuracy, increase in omissions, and increased response latency. The behavioral differences were not due to alterations in sensorimotor function or a diminished motivational state. Electrophysiological characterization of synaptic transmission in slices from the mPFC indicated an age-related decrease in glutamatergic transmission. In particular, a robust decrease inN-methyl-d-aspartate receptor (NMDAR)-mediated synaptic responses in the mPFC was correlated with several measures of attention. The decrease in NMDAR function was due in part to an altered redox state as bath application of the reducing agent, dithiothreitol, increased the NMDAR component of the synaptic response to a greater extent in middle-age animals. Together with previous work indicating that redox state mediates senescent physiology in the hippocampus, the results indicate that redox changes contribute to senescent synaptic function in vulnerable brain regions involved in age-related cognitive decline.
Executive Control Signals in Orbitofrontal Cortex during Response Inhibition
Authors: Bryden Daniel W. , Roesch Matthew R.
Published: March 2015

Orbitofrontal cortex (OFC) lesions produce deficits in response inhibition and imaging studies suggest that activity in OFC is stronger on trials that require suppression of behavior, yet few studies have examined neural correlates at the single-unit level in a behavioral task that probes response inhibition without varying other factors, such as anticipated outcomes. Here we recorded from single neurons in lateral OFC in a task that required animals in the minority of trials to STOP or inhibit an ongoing movement and respond in the opposite direction. We found that population and single-unit firing was modulated primarily by response direction and movement speed, and that very few OFC neurons exhibited a response independent inhibition signal. Remarkably, the strength of the directional signal was not diminished on STOP trials and was actually stronger on STOP trials during conflict adaptation. Finally, directional signals were stronger during sessions in which rats had the most difficulty inhibiting behavior. These results suggest that “inhibition” deficits observed with OFC interference studies reflect deficits unrelated to signaling the need to inhibit behavior, but instead support a role for OFC in executive functions related to dissociating between two perceptually similar actions during response conflict.
A Novel Mouse Model of Subcortical Infarcts with Dementia
Authors: Hattori Yorito , Enmi Jun-ichiro , Kitamura Akihiro , Yamamoto Yumi , Saito Satoshi , Takahashi Yukako , Iguchi Satoshi , Tsuji Masahiro , Yamahara Kenichi , Nagatsuka Kazuyuki , Iida Hidehiro , Ihara Masafumi
Published: March 2015

Subcortical white matter (WM) is a frequent target of ischemic injury and extensive WM lesions are important substrates of vascular cognitive impairment (VCI) in humans. However, ischemic stroke rodent models have been shown to mainly induce cerebral infarcts in the gray matter, while cerebral hypoperfusion models show only WM rarefaction without infarcts. The lack of animal models consistently replicating WM infarct damage may partially explain why many neuroprotective drugs for ischemic stroke or VCI have failed clinically, despite earlier success in preclinical experiments. Here, we report a novel animal model of WM infarct damage with cognitive impairment can be generated by surgical implantation of different devices to the right and left common carotid artery (CCA) in C57BL/6J mice. Implantation of an ameroid constrictor to the right CCA resulted in gradual occlusion of the vessel over 28 d, whereas placement of a microcoil to the left CCA induced ∼50% arterial stenosis. Arterial spin labeling showed a gradual reduction of cerebral blood flow over 28 d post operation. Such reductions were more marked in the right, compared with the left, hemisphere and in subcortical, rather than the cortical, areas. Histopathological analysis showed multiple infarct damage in right subcortical regions, including the corpus callosum, internal capsule, hippocampal fimbria, and caudoputamen, in 81% of mice. Mice displaying such damage performed significantly poorer in locomotor and cognitive tests. The current mouse model replicates the phenotypes of human subcortical VCI, including multiple WM infarcts with motor and cognitive impairment.
Neural Population Coding of Multiple Stimuli
Authors: Orhan A. Emin , Ma Wei Ji
Published: March 2015

In natural scenes, objects generally appear together with other objects. Yet, theoretical studies of neural population coding typically focus on the encoding of single objects in isolation. Experimental studies suggest that neural responses to multiple objects are well described by linear or nonlinear combinations of the responses to constituent objects, a phenomenon we call stimulus mixing. Here, we present a theoretical analysis of the consequences of common forms of stimulus mixing observed in cortical responses. We show that some of these mixing rules can severely compromise the brain's ability to decode the individual objects. This cost is usually greater than the cost incurred by even large reductions in the gain or large increases in neural variability, explaining why the benefits of attention can be understood primarily in terms of a stimulus selection, or demixing, mechanism rather than purely as a gain increase or noise reduction mechanism. The cost of stimulus mixing becomes even higher when the number of encoded objects increases, suggesting a novel mechanism that might contribute to set size effects observed in myriad psychophysical tasks. We further show that a specific form of neural correlation and heterogeneity in stimulus mixing among the neurons can partially alleviate the harmful effects of stimulus mixing. Finally, we derive simple conditions that must be satisfied for unharmful mixing of stimuli.
Coronin-1 and Calcium Signaling Governs Sympathetic Final Target Innervation
Authors: Suo Dong , Park Juyeon , Young Samuel , Makita Takako , Deppmann Christopher D.
Published: March 2015

Development of a functional peripheral nervous system requires axons to rapidly innervate and arborize into final target organs and then slow but not halt their growth to establish stable connections while keeping pace with organ growth. Here we examine the role of the NGF-TrkA effector protein, Coronin-1, on postganglionic sympathetic neuron final target innervation. In the absence of Coronin-1 we find that NGF-TrkA-PI3K signaling drives robust axon growth and branching in part by suppressing GSK3β. In contrast, the presence of Coronin-1 (wild-type neurons) suppresses but does not halt NGF-TrkA-dependent growth and branching. This relative suppression in axon growth behaviors is due to Coronin-1-dependent calcium release via PLC-γ1 signaling, which releases PI3K-dependent suppression of GSK3β. Finally, we demonstrate thatCoro1a−/−mice display sympathetic axon overgrowth and overbranching phenotypes in the developing heart. Together with previous work demonstrating the Coronin-1 expression is NGF dependent, this work suggests that periods before and after NGF-TrkA-induced Coronin-1 expression (and likely other factors) defines two distinct axon growth states, which are critical for proper circuit formation in the sympathetic nervous system.
Sensitivity of Locus Ceruleus Neurons to Reward Value for Goal-Directed Actions
Authors: Bouret Sebastien , Richmond Barry J.
Published: March 2015

The noradrenergic nucleus locus ceruleus (LC) is associated classically with arousal and attention. Recent data suggest that it might also play a role in motivation. To study how LC neuronal responses are related to motivational intensity, we recorded 121 single neurons from two monkeys while reward size (one, two, or four drops) and the manner of obtaining reward (passive vs active) were both manipulated. The monkeys received reward under three conditions: (1) releasing a bar when a visual target changed color; (2) passively holding a bar; or (3) touching and releasing a bar. In the first two conditions, a visual cue indicated the size of the upcoming reward, and, in the third, the reward was constant through each block of 25 trials. Performance levels and lipping intensity (an appetitive behavior) both showed that the monkeys' motivation in the task was related to the predicted reward size. In conditions 1 and 2, LC neurons were activated phasically in relation to cue onset, and this activation strengthened with increasing expected reward size. In conditions 1 and 3, LC neurons were activated before the bar-release action, and the activation weakened with increasing expected reward size but only in task 1. These effects evolved as monkeys progressed through behavioral sessions, because increasing fatigue and satiety presumably progressively decreased the value of the upcoming reward. These data indicate that LC neurons integrate motivationally relevant information: both external cues and internal drives. The LC might provide the impetus to act when the predicted outcome value is low.
Characterizing the Associative Content of Brain Structures Involved in Habitual and Goal-Directed Actions in Humans: A Multivariate fMRI Study
Authors: McNamee Daniel , Liljeholm Mimi , Zika Ondrej , O'Doherty John P.
Published: March 2015

While there is accumulating evidence for the existence of distinct neural systems supporting goal-directed and habitual action selection in the mammalian brain, much less is known about the nature of the information being processed in these different brain regions. Associative learning theory predicts that brain systems involved in habitual control, such as the dorsolateral striatum, should contain stimulus and response information only, but not outcome information, while regions involved in goal-directed action, such as ventromedial and dorsolateral prefrontal cortex and dorsomedial striatum, should be involved in processing information about outcomes as well as stimuli and responses. To test this prediction, human participants underwent fMRI while engaging in a binary choice task designed to enable the separate identification of these different representations with a multivariate classification analysis approach. Consistent with our predictions, the dorsolateral striatum contained information about responses but not outcomes at the time of an initial stimulus, while the regions implicated in goal-directed action selection contained information about both responses and outcomes. These findings suggest that differential contributions of these regions to habitual and goal-directed behavioral control may depend in part on basic differences in the type of information that these regions have access to at the time of decision making.