Dark Blue Crystals Research Articles

Radical cations of chalcogenanthrenes with halogenido metalate anions. Part I: tetramethoxythianthrene

Abstract The electron-rich molecule tetramethoxythianthrene TMO-TA can readily be oxidized to the radical cation using various transition metal halides in acetonitrile as solvent. Reactions with CuBr2, FeCl3, AuCl3, NbCl5, and CuCl2 yield dark blue or black crystals of [TMO-TA]2[CuBr4] (2), [TMO-TA][FeCl4] · CH3CN (3), [TMO-TA][AuCl4] (4), [TMO-TA][NbCl6] · CH3CN (6), and [TMO-TA]5[Cu2Cl6]2 · 2 CH3CN (7). [TMO-TA]2[Ta2OF10] (5) was obtained by anodic oxidation of TMO-TA in the presence of (Nbu4)2[Ta2OF10] as electrolyte. Using mercury(II) bromide, no redox reaction occurs. Instead, the colorless complex [HgBr2(TMO-TA)] (1) is formed. In the crystal structures of the compounds 2–7, the almost planar radical cations show different types of arrangements. Pair formation of the [TMO-TA]•+ radicals to [TMO-TA]2 2+ dimers with the typical intra-pair S⋯S bonds of 3.1–3.2 Å lengths is predominant. Compounds 6 and 7 contain stacks of planar TMO-TA molecules in equidistant arrangement without pair formation and the unique feature of rotation of each adjacent cation by about 30°. Compounds 2, 5, and 7 are electrical semiconductors with band gaps between 0.62 and 1.4 eV, reflecting the arrangement of the radical cations. While 5 is diamagnetic, the magnetic momenta of 2 and 7 correspond only to the expected paramagnetic momenta of magnetically dilute Cu2+ ions. Electrons on the organic radicals are strongly paired in all compounds.

Tetrahedral aluminum in tourmaline from a spinel-pargasite-metamorphosed mafic-ultramafic rock

Abstract Tourmaline is a widespread borosilicate mineral, which is well known for its variable chemistry. Although major amounts of octahedral Al in tourmaline is commonplace, the occurrence of significant amounts of tetrahedral Al is relatively rare. This paper focuses on tourmaline from the collection of the A.E. Fersman Mineralogical Museum (Russia) originated from Italy with up to 25% of Si replaced by Al at the tetrahedral site. The tourmaline is characterized by optical and scanning electron microscopy, Raman spectroscopy, infrared spectroscopy, Mössbauer spectroscopy, energy-dispersive and wavelength-dispersive X-ray analysis, laser ablation inductively coupled plasma optical emission spectrometry and single crystal X-ray diffraction. The studied tourmaline occurs as transparent dark blue crystals (with equant external morphology) up to 3 mm in size and forms veinlets cutting a (Mg,Al)-rich metamorphosed mafic-ultramafic rock (Mg≫Fe) composed of spinel, pargasite, clinochlore, phlogopite, and hydroxylapatite. The studied tourmaline meets the criteria defining magnesio-lucchesiite and can be compositionally formed via Tschermak-like ([6]Me2++[4]Si4+↔[6]Al3++[4]Al3+, where [6]Me2+=Mg, Fe) or plagioclase-like ([9]Ca2+ + [4]Al3+ ↔ [9]Na+ + [4]Si4+) substitutions. Zones with a relatively high Si content (Si-rich) have pronounced indications of dissolution, while silicon-depleted zones (Si-poor) overgrow Si-rich zones and eventually creates a visible replacement zone of the crystal. We suggest that Si-poor tourmaline result from the Si-rich tourmaline losing Si during a metasomatic process. The resulting empirical crystal-chemical formula for the Si-poor zone is: X(Ca0.95Na0.03□0.02)Σ1.00 Y(Mg1.08Al0.98Fe2+0.50Fe3+0.43)Σ3.00 Z(Al5.91Fe3+0.09)Σ6.00 T[(Si4.57Al1.43)Σ6.00O18] (BO3)3 V(OH)3 W[O0.95(OH)0.05]Σ1.00 (a = 15.9811(2), c = 7.12520(10) Å, R1 = 1.7 %) and for the Si-rich zone is: X(Ca0.89Na0.11)Σ1.00 Y(Mg1.55Al0.80Fe2+0.34Fe3+0.31)Σ3.00 Z(Al5.51Mg0.44Fe3+0.05)Σ6.00 T[(Si5.35Al0.65)Σ6.00O18] (BO3)3V(OH)3W[O0.93(OH)0.07]Σ1.00 (a=15.9621(3), c=7.14110(10) Å, R1=1.7 %). According to PT calculations of mineral assemblage stability and comparable data on synthetic [4]Al-rich tourmalines, the studied tourmaline was formed at 600–750 °C and 0.10-0.20 GPa. The formation of tetrahedral Al-rich tourmalines requires several unusual factors: (1) desilication of primary rocks and (2) high temperatures and relatively low pressures.

On the synthesis and structure of the copper-molybdenum oxide bronzes: Monoclinic Cu2Mo10O30 and orthorhombic CuMo9O26

Cu2Mo10O30 was prepared as a monophasic material comprising dark blue platy crystals by reacting Cu with MoO3 under argon at 550 ​°C. Single-crystal X-ray diffractometry showed that Cu2Mo10O30 is a stoichiometric compound that crystallizes with a monoclinic (C2/c) cell: a ​= ​16.6359(6); b ​= ​9.3112(3); c ​= ​27.1597(9) Å; β ​= ​102.621(3)° (Z ​= ​8). Electron paramagnetic resonance spectroscopy revealed that Cu2Mo10O30 displays mixed-valency; (CuI2−xCuIIx)(MoV2+xMoVI8−x)O30 (0 ​≪ ​x ​≤ ​2). Differential scanning calorimetry and in situ high-temperature powder X-ray diffractometry showed that Cu2Mo10O30 decomposes ≳550 ​°C under an inert atmosphere. Dark blue acicular crystals of CuMo9O26 were discovered as a side-product in materials prepared inside evacuated glass ampoules at 500 ​°C. Single-crystal X-ray diffractometry showed these to crystallize with an orthorhombic (Pmmn) cell: a ​= ​3.74190(10); b ​= ​26.4941(4); c ​= ​9.15300(10) Å; (Z ​= ​2). Rietveld refinement of the powder X-ray diffraction data for these materials revealed Cu2Mo10O30 with minor CuMo9O26 and ‘Cu0.1MoO3’.

Man-made blue and purple barium copper silicate pigments and the pabstite (BaSnSi3O9) mystery of ancient Chinese wall paintings from Luoyang

Man-made ancient Chinese barium copper silicate pigments: Chinese (Han) Purple, BaCuSi2O6; Chinese (Han) Blue, BaCuSi4O10; Chinese Dark Blue, BaCu2Si2O7 (in summary called Chinese blues), and platelet-like crystals of BaSnSi3O9 were detected on mural paintings of a tomb in Luoyang City, Henan Province, China, dated to Western Han Dynasty (206 BC–8 AD). The pigments of the LY01 and LY02 samples were analyzed by archaeometrical methods: powder X-ray diffractometry (XRD), scanning electron microscopy (SEM–EDX) and micro-Raman spectroscopy. While the artificial nature of the ancient barium copper silicates was undoubted, the synthetic or mineral origin of BaSnSi3O9 of these murals had to be clarified. Involvement of the rare mineral pabstite Ba(Sn,Ti,Zr)Si3O9 from the Tian Shan mountains could be ruled out due to absence of Ti and Zr in the elemental composition. Tin compounds as admixtures to the lead minerals—the latter required as flux additive for the preparation of the Chinese blues—or tin admixtures to pristine barium starting minerals could be excluded, as well as the use of tin containing mineral mushistonite (CuSn(OH)6), primarily intended to be applied as copper source. Related to the findings for the production of Egyptian Blue (CaCuSi4O10), bronze or bronze scrap including also corroded material was used intending copper recycling. For the synthesis of the Luoyang Chinese blues only low amounts of bronze or bronze scrap were required providing the additional advantage to form in presence of air a tin/lead oxide flux with lowered vitrification temperatures and viscosities. This marked the advent of an ‘innovative production technology’ avoiding addition of large amounts of lead minerals as an effective lead-only flux. Despite of the chemical similarity to production of Egyptian Blue, the tin/lead based developments for the Chinese blues were anticipated to be independent excluding technology transfer from ancient Egypt. For further substantiation of the appearance of pabstite in the Luoyang Chinese blues a contemporary independent synthesis was sought, carried out under conditions similar to those of the barium copper silicate syntheses (1000 °C, but absence of a flux) starting from cassiterite (SnO2), quartz (SiO2) and witherite (BaCO3).

A Reversible Redox Reaction in a Keggin Polyoxometalate Crystal Driven by Visible Light: A Programmable Solid-State Photochromic Switch.

The colourless crystals of (PPh4 )3 [PW12 O40 ]⋅3 C3 H7 NO (1) are converted to the dark blue crystals of {(PPh4 )3 [PW12 O40 ]⋅3C3 H7 NO}0.85 {(PPh4 )3 (C3 H7 NO)+. [PWV WVI11 O40 ]- ⋅2C3 H7 NO)}0.15 (2) upon irradiation with visible light in an interesting single crystal to single crystal transformation. This photochromic conversion is accompanied by the reduction of concerned Keggin anion from {PWVI12 } to {PWV WVI11 }. This redox conversion is characterized by various spectroscopic techniques including single crystal X-ray diffraction studies. The photochromic properties of compound 1 can be controlled reversibly through the dimethylformamide (DMF) molecule as a function of temperature and proton exposure in a gas-solid reaction. The present work can be described as a new concept of programmable photochromism with the formation of photochromic pockets in crystalline 1 host (solid state), wherein a solvent can be plugged at a time to show light induced coloration.

An Isolable Diboron‐Centered Diradical with a Triplet Ground State

Two new diboranes, 2,6-bis(BMes2 )mesitylene (1) and 3,3'-bis(BMes2 )bimesitylene (3), were synthesized. Two-electron reduction of 1 with elemental potassium afforded the C-H activation product [(18-c-6)K(THF)2 ]2+ ⋅22- bearing a BC3 four-membered ring as colorless crystals, whereas the reduction of 3 with potassium led to the isolation of [(18-c-6)K(THF)2 ]2+ ⋅32-.. as dark blue crystals. Both reduction products were characterized by structural and spectroscopic methods. Electron paramagnetic resonance (EPR) spectroscopy and theoretical calculations revealed that the electron spin density of 32-.. mainly resides on the two boron nuclei and features a triplet ground state, which was confirmed by superconducting quantum interference device (SQUID) measurements as well as theoretical calculations. 32-.. represents the first structurally characterized boron-centered diradical with a triplet ground state. In addition, the reactivity of [(18-c-6)K(THF)2 ]2+ ⋅32-.. toward PhSeSePh and nBu3 SnH was investigated, which is consistent with its radical character.

Anion exchange coupled with the reduction and dimerisation of a copper(ii) nitrate complex of tripyridyl dithioether via a single-crystal-to-single-crystal transformation.

It is a challenge to develop methodologies involving multiple transformations for preparing new materials that cannot be obtained via direct synthesis. Herein, we report an anion exchange process accompanying cation reduction and dimerisation via a single-crystal-to-single-crystal transformation. First, a direct reaction of the flexible tripyridyl dithioether ligand L with CuI afforded a mixture of four bis(ligand) complexes (1a-1d). To avoid the formation of undesired mixed products, a copper(ii) nitrate complex-mediated approach involving anion exchange and cation reduction was employed to generate a monomeric complex, [CuII(L)NO3]NO3·toluene (2). When the dark blue crystals of 2 were immersed in an aqueous NaI solution, the crystals were transformed to a pale yellow dimeric copper(i) iodide complex, [(μ-CuI2I2)(L)2] (3). The observed anion exchange promotes the reduction of copper(ii) to copper(i) at the expense of I-/I3- oxidation as well as dimerisation via the formation of a Cu2I2 cluster. This result corresponds to the synthesis of a compound that otherwise was not able to be prepared via a direct synthetic procedure.

Linarite from the Ag-Pb ore deposit at Kletné near Suchdol nad Odrou (Jeseníky Culm, Vítkov Highlands)

Abstract Linarite, PbCu2+(SO4)(OH)2, and associated minerals were studied at new locality near Kletné, where they occur in dump material of historic Ag-Pb mines exploited during the 16th century. Linarite forms thin blue coatings and tiny dark blue crystals (<1 mm in size) in small cavities, in assemblage with cerussite, brochantite and supergene copper sulfides. Mineral was identified by chemical analyses (electron microprobe), Raman spectroscopy and powder X-ray diffraction analysis. Chemical composition of the studied linarite can be expressed by empirical formula Pb0.98Cu1.06(SO4)Σ0.96(OH)2.15 and its refined unit-cell parameters are: a = 9.6944(3), b = 5.6499(2), c = 4.6846(1) Å, ß = 102.669(3)° and V = 250.50(1) Å3. Linarite formed together with other supergene minerals in the oxidation zone of the deposit by weathering of Pb- and Cu-sulphides.

Copper dimethylmalonate coordination polymers with 4,4′-bipyridine coligands: Kinetic and thermodynamic products with different dimensionalities

Slow diffusion of an ethanolic solution of 4,4′-bipyridine (bpy) into an aqueous solution of copper dimethylmalonate (dmmal) afforded two different coordination polymer complexes as time elapsed. These were structurally characterized via single-crystal X-ray diffraction. A small amount of light blue crystals of {[Cu2(dmmal)2(bpy)1.5(H2O)]·2H2O}n (1) were initially deposited at the solution interface. Compound 1 displays a 3,4-connected 2D layer with an unprecedented (426)(42638) topology comprising alternating rows of hexagonal and rectangular circuits. These crystals dissolved as the reaction continued, with dark blue crystals of {[Cu3(dmmal)3(bpy)3(H2O)4]·H2O}n (2) forming at the bottom of the reaction vessel. Compound 2 manifests a 4-connected self-penetrated 658 cds topology. Thermal properties of 2 are also reported.

Vanadium(V) complexes of a tripodal ligand, their characterisation and biological implications.

The reaction of the tripodal tetradentate dibasic ligand 6,6'-(2-(pyridin-2-yl)ethylazanediyl)bis(methylene)bis(2,4-di-tert-butylphenol), H2L(1)I, with [V(IV)O(acac)2] in CH3CN gives the V(V)O-complex, [V(V)O(acac)(L(1))] 1. Crystallisation of 1 in CH3CN at ∼0 °C gives dark blue crystals of 1, while at room temperature it affords dark green crystals of [{V(V)O(L(1))}2μ-O] 3. Upon prolonged treatment of 1 in MeOH, [V(V)O(OMe)(MeOH)(L(1))] 2 is obtained. All three complexes were analysed by single-crystal X-ray diffraction, depicting a distorted octahedral geometry around vanadium. In the reaction of H2L(1) with V(IV)OSO4 partial hydrolysis of the tripodal ligand results in the elimination of the pyridyl fragment of L(1) and the formation of H[V(V)O2(L(2))] 4 containing the ONO tridentate ligand 6,6'-azanediylbis(methylene)bis(2,4-di-tert-butylphenol), H2L(2)II. Compound 4, which was not fully characterised, undergoes dimerization in acetone yielding the hydroxido-bridged [{V(V)O(L(2))}2μ-(OH)2] 5 having a distorted octahedral geometry around each vanadium. In contrast, from a solution of 4 in acetonitrile, the dinuclear compound [{V(V)O(L(2))}2μ-O] 6 is obtained, with a trigonal bipyramidal geometry around each vanadium. The methoxido complex 2 is successfully employed as a functional catechol-oxidase mimic in the oxidation of catechol to o-quinone under air. The process was confirmed to follow a Michaelis-Menten type kinetics with respect to catechol, the Vmax and KM values obtained being 7.66 × 10(-6) M min(-1) and 0.0557 M, respectively, and the turnover frequency is 0.0541 min(-1). A similar reaction with the bulkier 3,5-di-tert-butylcatechol proceeded at a much slower rate. Complex 2 was also used as a catalyst precursor for the oxidative bromination of thymol in aqueous medium. The selectivity shows quite interesting trends, namely when not using excess of the primary oxidizing agent, H2O2, the para mono-brominated product corresponds to ∼93% of the products and no dibromo derivative is formed.

Dual Inhibition of Met Kinase and Angiogenesis to Overcome HGF-Induced EGFR-TKI Resistance in EGFR Mutant Lung Cancer

Acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) is a serious problem in the management of EGFR mutant lung cancer. We recently reported that hepatocyte growth factor (HGF) induces resistance to EGFR-TKIs by activating the Met/PI3K pathway. HGF is also known to induce angiogenesis in cooperation with vascular endothelial growth factor (VEGF), which is an important therapeutic target in lung cancer. Therefore, we hypothesized that dual inhibition of HGF and VEGF may be therapeutically useful for controlling HGF-induced EGFR-TKI-resistant lung cancer. We found that a dual Met/VEGF receptor 2 kinase inhibitor, E7050, circumvented HGF-induced EGFR-TKI resistance in EGFR mutant lung cancer cell lines by inhibiting the Met/Gab1/PI3K/Akt pathway in vitro. HGF stimulated VEGF production by activation of the Met/Gab1 signaling pathway in EGFR mutant lung cancer cell lines, and E7050 showed an inhibitory effect. In a xenograft model, tumors produced by HGF-transfected Ma-1 (Ma-1/HGF) cells were more angiogenic than vector control tumors and showed resistance to gefitinib. E7050 alone inhibited angiogenesis and retarded growth of Ma-1/HGF tumors. E7050 combined with gefitinib induced marked regression of tumor growth. Moreover, dual inhibition of HGF and VEGF by neutralizing antibodies combined with gefitinib also markedly regressed tumor growth. These results indicate the therapeutic rationale of dual targeting of HGF-Met and VEGF-VEGF receptor 2 for overcoming HGF-induced EGFR-TKI resistance in EGFR mutant lung cancer.

Complex Regulation of p73 Isoforms after Alteration of Amyloid Precursor Polypeptide (APP) Function and DNA Damage in Neurons

Genetic ablations of p73 have shown its implication in the development of the nervous system. However, the relative contribution of ΔNp73 and TAp73 isoforms in neuronal functions is still unclear. In this study, we have analyzed the expression of these isoforms during neuronal death induced by alteration of the amyloid-β precursor protein function or cisplatin. We observed a concomitant up-regulation of a TAp73 isoform and a down-regulation of a ΔNp73 isoform. The shift in favor of the pro-apoptotic isoform correlated with an induction of the p53/p73 target genes such as Noxa. At a functional level, we showed that TAp73 induced neuronal death and that ΔNp73 has a neuroprotective role toward amyloid-β precursor protein alteration or cisplatin. We investigated the mechanisms of p73 expression and found that the TAp73 expression was regulated at the promoter level. In contrast, regulation of ΔNp73 protein levels was regulated by phosphorylation at residue 86 and multiple proteases. Thus, this study indicates that tight transcriptional and post-translational mechanisms regulate the p73 isoform ratios that play an important role in neuronal survival.

A Blue Corrinoid from Partial Degradation of Vitamin B12in Aqueous Bicarbonate: Spectra, Structure, and Interaction with Proteins of B12Transport

Cobalamin (Cbl) is a complex cofactor produced only by bacteria but used by all animals and humans. Cyanocobalamin (vitamin B(12), CNCbl) is one commonly isolated form of cobalamin. B(12) belongs to a large group of corrinoids, which are characterized by a distinct red color conferred by the system of conjugated double bonds of the corrin ring retaining a Co(III) ion. A unique blue Cbl derivative was produced by hydrolysis of CNCbl in a weakly alkaline aqueous solution of bicarbonate. This corrinoid was purified and isolated as dark blue crystals. Its spectroscopic analysis and X-ray crystallography revealed B-ring opening with formation of 7,8-seco-cyanocobalamin (7,8-sCNCbl). The unprecedented structural change was caused by cleavage of the peripheral C-C bond between saturated carbons 7 and 8 of the corrin macrocycle accompanied by formation of a C═C bond at C7 and a carbonyl group at C8. Additionally, the C-amide was hydrolyzed to a carboxylic acid. The extended conjugation of the π-system caused a considerable red shift of the absorbance spectrum. Formation and degradation of 7,8-sCNCbl were analyzed qualitatively. Its interaction with the proteins of mammalian Cbl transport revealed both a slow binding kinetics and a low overall affinity. The binding data were compared to those of other monocarboxylic derivatives and agreed with the earlier proposed scheme for two-step ligand recognition. The obtained results are consistent with the structural models of 7,8-sCNCbl and the transport proteins intrinsic factor and transcobalamin. Potential applications of the novel derivative for drug conjugation are discussed.

An uncommon case of a suicide with inhalation of hydrogen cyanide

An uncommon suicide by oral ingestion of potassium cyanide salts and contemporaneous inhalation of hydrogen cyanide is presented. A 48-year-old tradesman was found dead sitting in his car. A penetrating odor of bitter almonds was noticed when opening the doors. A camping stove and a cooking pot containing large amounts of dark blue crystals were found in the footwell of the car. White powder adhered to his fingers and to the area around the mouth. Furthermore bottles containing potassium ferrocyanide and different kinds of acid and leach were found in the car together with internet information about, e.g. potassium ferrocyanide and potassium cyanide. At autopsy hemorrhages and erosions of the mucosa of the respiratory tract, esophagus and stomach were found. Concentrations of cyanide were 0.2 mg/l in stomach contents, 0.96 mg/kg in brain tissue, 2.79 mg/kg in lungs, and 5.3 mg/l in blood. The white and toxic powder potassium cyanide was formed by heating of the yellow crystals of potassium ferrocyanide on the camping stove. This powder was probably ingested orally. Addition of acid converted the salt into the highly toxic gas hydrogen cyanide. Oxidation with atmospheric oxygen built the dark blue ferrous compound Prussian blue. This case report of a person who was not familiar with chemicals demonstrates the acquisition of professional information via the internet, enabling a suicide with a complex procedure.

Engineering Three-Dimensional Chains of Porous Nanoballs from a 1,2,4-Triazole-carboxylate Supramolecular Synthon

Glycine ethyl ester was recruited in an amine exchange process based on a transamination to afford ethyl 4H-,2,4-triazol-4-yl-acetate (L1). The acid hydrolysis of this molecule leads to quantitative isolation of 4H-1,2,4-triazol-4-yl acetic acid (L2). This versatile synthon crystallizes in a noncentrosymmetric orthorhombic space group (Fdd2) with Z = 16. This crystal structure is the first one for a 1,2,4-triazole ligand constructed from an amino acid derivative. The strong intermolecular hydrogen bonding O-H center dot center dot center dot N (2.570(3) angstrom) connects molecules into infinite one-dimensional chains running parallel to the b axis, and the structure is further extended by numerous but moderate strength hydrogen bonds (C-H center dot center dot center dot O). Prominent features of L2 are the presence of diverse potential coordinating groups such as carboxylic acid and triazole on the same framework as well as the inherent flexibility of the ligand backbone. Reaction of L1 or L2 with aq. Cu(BF4)(2) in aq. DMF gives dark blue crystals which crystallize in a noncentrosymmetric, cubic space group (1 (4) over bar 3m) and which were formulated as [Cu-3(mu(3)-O)(L2)(3). (H2O)(3)]BF4 center dot H2O (C1). The self-assembly of C3-symmetric, mu(3)-oxo bridged triangular tricopper secondary building blocks (SBB) formed an unique architecture which encompasses voluminous nanoball voids of 1 nm. The total solvent accessible volume is 4477.5 angstrom(3) which accounts for 48% of the cell volume. The crystal network stability was studied by thermogravimetric analysis (TGA) differential thermal analysis (DTA) and scanning electron microscopy (SEM) analyses. Sorption properties and gas storage capacities were measured by BET. CI shows no preference for N-2(g), but a reversible H-2(g) uptake of 21 cm(3)/g was observed, Morphology analysis by SEM on single crystals of CI shows ultrawells of square shape irregularly located on the surface, whose origin is due to desolvation or crystal defects. Mercury porosimetry measurements reveal pore size distribution with a diameter ranging from 350 nm to 2.3 mu m.

Hydrothermal synthesis and characterization of (N(C2H5)4)4[VMo12V2O44

AbstractThe hydrothermal reaction of a mixture of Na2MoO4·2H2O, V2O5, pyromellitic acid (1,2,4,5‐C6H2(COOH)4), (C2H5)4NCl and 0,1 M H2SO4 for 88 h at 180°C gives blue needle‐like crystals of [VIV2O2(H2O)2 (C6H2(COO)4)] in 20% yield (based on V) and dark blue prismatic crystals of the title compound, mixed‐valance (N(C2H5)4)4[VMo12V2O44], 1, in 12% yield (based on Mo). 1 was investigated by means of elemental analysis, thermogravimetry, Fourier Transform Infrared Spectroscopy and Single Crystal X‐ray Diffraction Methods. Crystal data for the compound: monoclinic space group P21/c (No:14), a=13.7815(12) b=13.0271(9) c= 21.189(2) Å, β= 113.909(7)°, Z=2. Although [XM14O42]‐n (X=P, Si, Ge, V and M=Mo and/or V) cores have been previously determined, this is the first time that [VMo12V2O44]‐4 core is synthesized and characterized. The structural difference between 1 and these HPOMs is the coordinational geometry of the central metal atoms. The central vanadium in 1 has an octahedral coordination geometry, whereas in literature, the central V, P, Si and Ge atoms in [V15O42]‐9 / [SiM8V6O42]‐4 / [PM8V6O42]‐5 / [GeM8V6O42]‐4 have tetrahedral coordinational geometry. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Calcium-mediated Transient Phosphorylation of Tau and Amyloid Precursor Protein Followed by Intraneuronal Amyloid-β Accumulation

Intraneuronal accumulation of hyperphosphorylated protein tau in paired helical filaments together with amyloid-beta peptide (Abeta) deposits confirm the clinical diagnosis of Alzheimer disease. A common cellular mechanism leading to the production of these potent toxins remains elusive. Here we show that, in cultured neurons, membrane depolarization induced a calcium-mediated transient phosphorylation of both microtubule-associated protein tau and amyloid precursor protein (APP), followed by a dephosphorylation of these proteins. Phosphorylation was mediated by glycogen synthase kinase 3 and cyclin-dependent kinase 5 protein kinases, while calcineurin was responsible for dephosphorylation. Following the transient phosphorylation of APP, intraneuronal Abeta accumulated and induced neurotoxicity. Phosphorylation of APP on Thr-668 was indispensable for intraneuronal accumulation of Abeta. Our data demonstrate that an increase in cytosolic calcium concentration induces modifications of neuronal metabolism of APP and tau, similar to those found in Alzheimer disease.

Preparation of Poly(diiododiacetylene), an Ordered Conjugated Polymer of Carbon and Iodine

Conjugated organic polymers generally must include large substituents for stability, either contained within or appended to the polymer chain. In polydiacetylenes, the substituents fulfill another important role: During topochemical polymerization, they control the spacing between the diyne monomers to produce an ordered polymer. By using a co-crystal scaffolding, we have prepared poly(diiododiacetylene), or PIDA, a nearly unadorned carbon chain substituted with only single-atom iodine side groups. The monomer, diiodobutadiyne, forms co-crystals with bis(nitrile) oxalamides, aligned by hydrogen bonds between oxalamide groups and weak Lewis acid-base interactions between nitriles and iodoalkynes. In co-crystals with one oxalamide host, the diyne undergoes spontaneous topochemical polymerization to form PIDA. The structure of the dark blue crystals, which look copper-colored under reflected light, has been confirmed by single-crystal x-ray diffraction, ultraviolet-visible absorption spectroscopy, and scanning electron microscopy.

Lithium Chloride Increases the Production of Amyloid-β Peptide Independently from Its Inhibition of Glycogen Synthase Kinase 3

Glycogen synthase kinase 3 (GSK3) is able to phosphorylate tau at many sites that are found to be phosphorylated in paired helical filaments in Alzheimer disease. Lithium chloride (LiCl) efficiently inhibits GSK3 and was recently reported to also decrease the production of amyloid-beta peptide (Abeta) from its precursor, the amyloid precursor protein. Therefore, lithium has been proposed as a combined therapeutic agent, inhibiting both the hyperphosphorylation of tau and the production of Abeta. Here, we demonstrate that the inhibition of GSK3 by LiCl induced the nuclear translocation of beta-catenin in Chinese hamster ovary cells and rat cultured neurons, in which a decrease in tau phosphorylation was observed. In both cellular models, a nontoxic concentration of LiCl increased the production of Abeta by increasing the beta-cleavage of amyloid precursor protein, generating more substrate for an unmodified gamma-secretase activity. SB415286, another GSK3 inhibitor, induced the nuclear translocation of beta-catenin and slightly decreased Abeta production. It is concluded that the LiCl-mediated increase in Abeta production is not related to GSK3 inhibition.

Colon Cancer Cell-Derived High Mobility Group 1/Amphoterin Induces Growth Inhibition and Apoptosis in Macrophages

High mobility group (HMGB)1/amphoterin is a multifunctional cytokine involved in invasion and metastasis of cancer and in inflammation. To investigate HMGB1/amphoterin effects on macrophages, U937 human monocytic leukemia cells and rat peritoneal and human alveolar macrophages were examined. U937 cells expressed low levels of an HMGB1/amphoterin receptor, receptor for advanced glycation end-products (RAGE), whereas RAGE production was induced in differentiated phorbol 12-myristate 13-acetate (PMA)-U937 cells. Treatment with cultured medium of HMGB1/amphoterin-secreting WiDr human colon cancer cells showed growth inhibition of both U937 and PMA-U937 cells and apoptosis in PMA-U937 cells. The number of PMA-U937 cells was markedly decreased by co-culture with WiDr cells exposed to HMGB1/amphoterin sense S-oligodeoxynucleotide (ODN) in spheroids or monolayers. In contrast, PMA-U937 cells co-cultured with WiDr cells exposed to HMGB1/amphoterin anti-sense S-ODN were preserved in number. PMA-U937 cells exposed to RAGE anti-sense S-ODN were insensitive to WiDr-cultured medium. Recombinant human HMGB1/amphoterin induced growth inhibition in thioglycollate-induced rat peritoneal macrophages, PMA-U937 cells, and human alveolar macrophages, an effect that was abrogated by absorption with anti-HMGB1 antibody. Phosphorylation of JNK and Rac1 was induced in PMA-U937 cells treated with HMGB1/amphoterin. These results suggest that HMGB1/amphoterin induces growth inhibition and apoptosis in macrophages through RAGE intracellular signaling pathway.