Dependence of intramolecular valence delocalization on crystal form in mixed-valence trinuclear iron phenylacetate [Fe 2 III FeIIO(PhCH2CO2)6(py)3]

A dependence of intramolecular valence delocalization on crystal form in mixed-valence trinuclear iron phenylacetate [Fe ₂ ^III Fe^IIO(PhCH₂CO₂)₆(py)₃] was found. This complex was obtained in two different crystal forms: a columnar and a needle crystal form. Mössbauer spectra of the columnar crystals show a temperature-dependent valence delocalization, while the needle crystals show a trapped mixed-valence state from a lower temperature up to room temperature.     

Mössbauer spectroscopic studies of MIIMIVS3 (MII=Sn,Pb; MIV=Sn,Ge, Hf) and PbSnS2Se

Temperature-dependent Mössbauer experiments have been carried out to examine the lattice dynamical properties of tin sites in Sn₂S₃ and its related compounds. The differences in the lattice parameters, estimated from the temperature dependence of the area intensities for the compounds, are attributed to the characteristics of their crystal structures.     

99Ru,61Ni,57Fe,and119Sn Mössbauer studies of Heusler alloys containing ruthenium

⁹⁹Ru,⁶¹Ni,⁵⁷Fe and¹¹⁹Sn Mössbauer spectroscopic studies were made on ternary intermetallic compounds containing ruthenium, Ru_xY_3?xZ (Y=Fe, Ni; Z=Si, Sn). In the system of Ru_xFe_3?xSi, two different hyperfine magnetic fields were observed at the⁹⁹Ru nuclei (H _hf[Ru]) in the range ofx≤1.0 and the magnitude of eachH _hf[Ru] was found to decrease with an increase in the ruthenium concentrationx. Both the⁹⁹Ru and¹¹⁹Sn Mössbauer spectra of Ru₂FeSn could be analyzed with two sets of magnetically split lines. The⁶¹Ni Mössbauer spectra of Ru₂NiSn were obtained at 5 and 77 K.     

A note on asymptotic solutions for heat transfer in laminar forced flow against a non-isothermal rotating disk

Exact asymptotic expansions for heat transfer in laminar forced flow against a non-isothermal rotating disk are obtained for large and small Prandtl numbers using a perturbation method. The surface temperature of the disk is assumed to vary according to a power law with the radial distance. The results point out the erroneous terms in the existing asymptotic solutions and give the further higher order corrections to them.

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Zusammenfassung Mit Hilfe einer Störungsmethode werden exakte asymptotische Entwicklungen für den Wärmeübergang in laminarer Zwangskonvektion gegen eine nichtisotherme rotierende Scheibe für kleine und große Prandtl-Zahlen erhalten. Die Oberflächentemperatur soll nach einem Potenzgesetz vom Radius abhängen. Die Ergebnisse zeigen die Fehler in den bisherigen Lösungen auf und geben die Korrekturen höherer Ordnung.

     

Multivariate analysis of extremely large ToFSIMS imaging datasets by a rapid PCA method

Principal component analysis (PCA) and other multivariate analysis methods have been used increasingly to analyse and understand depth profiles in X‐ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and secondary ion mass spectrometry (SIMS). These methods have proved equally useful in fundamental studies as in applied work where speed of interpretation is very valuable. Until now these methods have been difficult to apply to very large datasets such as spectra associated with 2D images or 3D depth‐profiles. Existing algorithms for computing PCA matrices have been either too slow or demanded more memory than is available on desktop PCs. This often forces analysts to ‘bin’ spectra on much more coarse a grid than they would like, perhaps even to unity mass bins even though much higher resolution is available, or select only part of an image for PCA analysis, even though PCA of the full data would be preferred. We apply the new ‘random vectors’ method of singular value decomposition proposed by Halko and co‐authors to time‐of‐flight (ToF)SIMS data for the first time. This increases the speed of calculation by a factor of several hundred, making PCA of these datasets practical on desktop PCs for the first time. For large images or 3D depth profiles we have implemented a version of this algorithm which minimises memory needs, so that even datasets too large to store in memory can be processed into PCA results on an ordinary PC with a few gigabytes of memory in a few hours. We present results from ToFSIMS imaging of a citrate crystal and a basalt rock sample, the largest of which is 134GB in file size corresponding to 67 111 mass values at each of 512 × 512 pixels. This was processed into 100 PCA components in six hours on a conventional Windows desktop PC. © 2015 The Authors. Surface and Interface Analysis published by John Wiley & Sons Ltd.     

Polymerization of optically active disubstituted acetylene monomers by Pd catalyst bearing bulky phosphine ligand

Chloro- and aryl-substituted acetylene monomers having an optically active group were polymerized by a Pd catalyst [(^tBu₃P)PdMeCl] bearing a bulky phosphine ligand, and by MoCl₅ for comparison. The corresponding disubstituted acetylene polymers with M_n's = 2000–19,500 and 6900–10,800 were obtained in 29–83% and 11–62% yields when the Pd and Mo catalysts were used, respectively. The formation of polyacetylenes, poly[(R)- 1p ], poly[(R)- 1m ], and poly[(S)- 2p ] were confirmed by SEC and the presence of a Raman scattering peak based on the alternating double bonds of the main chain. Pd-based poly[(R)- 1m ] exhibited CD signals around 350 nm assignable to a certain secondary structure, while Mo-based poly[(R)- 1m ] did not. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3011–3016     

Duplicated ring enlargement of 4,9-methanothia[11]annulene to 6,11-methanothia[15]annulene

3,10-Dipyrrolidinyl-4,9-methanothia[11]annulene reacts with excess dimethyl acetylenedicarboxylate (DMAD) in refluxing toluene to give ring-enlarged 6,11-methanothia[15]annulene. X-ray crystallographic analysis of the product shows two different cis,trans-dienyl parts in the ring system. Product formation possibly involves π-facial selective addition of the enamine with DMAD and torque-selective ring opening of the intermediate cyclobutenes.     

A novel small molecule fluorescent sensor for Zn2+ based on pyridine-pyridone scaffold

The development of a water-soluble and small molecular weight fluorescent probe, 3-(4-methoxyphenyl)-4-(methylsulfanyl)-6-(pyridin-2-yl)pyridin-2(1H)-one (3), for detecting Zn²⁺ based on pyridine-pyridone skeleton is reported. We observed a clear chelation enhanced fluorescence effect of 3 in the presence of Zn²⁺. Other fluorescent properties of 3 are discussed.     

Phosphoproteome Profiling Using a Fluorescent Phosphosensor Dye in Two-Dimensional Polyacrylamide Gel Electrophoresis

We validated the novel PhosphoQUANTI SolidBlue Complex (PQSC) dye for the sensitive fluorescent detection of phosphorylated proteins in polyacrylamide- and two-dimensional gel electrophoresis (PAGE and 2DE, respectively). PQSC can detect as little as 15.6 ng of ß-casein, a pentaphosphorylated protein, and 61.3 ng of ovalbumin, a diphosphorylated protein. Fluorescence intensity correlates with the number of phosphorylated residues on the protein. To demonstrate the specificity of PQSC for phosphoproteins, enzymatically dephosphorylated lysates of Swiss 3T3 cells were separated in 2DE gels and stained by PQSC. The fluorescence signals in these gels were markedly reduced following dephosphorylation. When the phosphorylated proteins in Swiss 3T3 cell lysates were concentrated using a phosphoprotein enrichment column, the majority of phosphoproteins showed fluorescence signals in the pI 4–5 range. Finally, we performed phosphoproteome analysis to study differences in the protein phosphorylation profiles of proliferating and quiescent Swiss 3T3 cells. Over 135 discernible protein spots were detected, from which a selection of 15 spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF-MS). The PQSC staining procedure for phosphoprotein detection is simple, reversible, and fully compatible with MALDI TOF-MS.