Accurate electronic density of states for metallic Cu within a simple resonance-parameter approach

We combine the accurate resonance-parameter approach to transition-metal band structure, in the final version of Pettifor, with a Gilat-Raubenheimer method resorting to a dissection of the irreducible wedge into tetradedra to calculate the electronic density of states of f.c.c. Cu. Such an approach allows avoiding of any interpolation procedure.     

Critique of the theories of cyclotron resonance lineshape

Argyres-Sigel's critique of the theories of cyclotron resonance lineshape obtained by Kawabata and by Lodder and Fujita is reviewed. All the higher order terms in the expansion of the lineshape functions are proved to be finite at the resonance peaks as well as in the wings of the absorption lines, implying that the critique is unreasonable.     

Chemistry of mixed ligand complexes of platinum: crystal and molecular structure of trans-[PtCl(CH3)(PEt3)(AsPh3)]

The dimethyl platinum(II) complex containing mixed ligands, cis-[Pt(CH₃)₂(PEt₃)(AsPh₃)] reacted with one equivalent of hydrogen chloride yielding trans-[PtCl(CH₃)(PEt₃)(AsPh₃)]. The X-ray crystal structure of the molecule shows the trans orientation of the PEt₃ and AsPh₃ ligands.     

Studies of magnetic resonance phenomena in polymers. I. The effects of free volume and segmental mobility on the motion of nitroxide spin probes and labels in poly(methyl methacrylate)

Thin films of spin-probed and spin-labeled poly(methyl methacrylate) (PMMA) have been examined by electron spin resonance (ESR) at X-band frequency (9.2 GH_z) and at various temperatures. Direct spectral evidence is presented to indicate that the composite ESR spectra observed in a certain temperature range originate from two states of distinctly different mobility, one with slow motions corresponding to a glassy state and the other with fast motions corresponding to a liquidlike state. The coexistence of these two states at temperatures considerably below the glass transition temperature can be explained as a result of the effect of free volume in a solid polymeric glass.     

Estimation of the nonstructural contribution to the gibbs free energy of aluminum at melting

Summary We report a simple estimation of the variations in entropy and free energy of aluminum at melting based on the separation of the total internal energy into structural and nonstructural contributions. We make use of an interionic potential calculated from first principles.

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Riassunto Si riporta una semplice stima delle variazioni relative all’entropia ed all’energia libera dell’alluminio nel processo di fusione. Tale stima è fatta in base alla separazione dell’energia interna totale in due contributi: strutturale e non strutturale. Si fa uso di un potenziale interionico calcolato da principi primi.

     

A study of the spectra and acidity of 4,5-dihydro-1H-benz[g]indazol-7-ol and 2,3a,4,5-tetrahydro-7-hydroxy-3a-methyl-3H-benz[g]indazol-3-one

The synthesis of 2,3a,4,5-tetrahydro-7-hydroxy-3H-benz[g]indazol-3-one is recorded for the first time. Infrared, pmr, and uv spectral analysis of this pyrazolone and of 4,5-dihydro-1H-benz[g]indazol-7-ol strongly support the presence of one tautomer in each case. Measurements of pK_a values are in agreement with the proposed tautomeric structures based upon comparisons with simpler model systems. The data are taken in aqueous solution since the compounds are soluble at 10^?5 M and the results may more closely approximate that for the structure under physiological conditions.     

The Utility of Accurate Mass and LC Elution Time Information in the Analysis of Complex Proteomes

The combination of mass and normalized elution time (NET) of a peptide identified by liquid chromatography-mass spectrometry (LC-MS) measurements can serve as a unique signature for that peptide. However, the specificity of an LC-MS measurement depends upon the complexity of the proteome (i.e., the number of possible peptides) and the accuracy of the LC-MS measurements. In this work, theoretical tryptic digests of all predicted proteins from the genomes of three organisms of varying complexity were evaluated for specificity. Accuracy of the LC-MS measurement of mass-NET pairs (on a 0 to 1.0 NET scale) was described by bivariate normal sampling distributions centered on the peptide signatures. Measurement accuracy (i.e., mass and NET standard deviations of +/-0.1, 1, 5, and 10 ppm, and +/-0.01 and 0.05, respectively) was varied to evaluate improvements in process quality. The spatially localized confidence score, a conditional probability of peptide uniqueness, formed the basis for the peptide identification. Application of this approach to organisms with comparatively small proteomes, such as Deinococcus radiodurans, shows that modest mass and elution time accuracies are generally adequate for confidently identifying most peptides. For more complex proteomes, more accurate measurements are required. However, the study suggests that the majority of proteins for even the human proteome should be identifiable with reasonable confidence by using LC-MS measurements with mass accuracies within +/-1 ppm and high efficiency separations having elution time measurements within +/-0.01 NET.     

Synthesis and properties of an Au(III) complex with N-nitrosated ethylenediamine AuEn(ONNC2H4,NH2) (ClO4)2

Conclusions The feasibility of the isolation of an N-nitrosoamidated ethylenediamine product in an Au(III) complex has been demonstrated for the first time; this has previously been observed only in the case of Pt(IV) complexes. The compound was characterized by elemental analysis and by spectroscopic studies.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2654–2659, December, 1987.     

Stereochemistry of cis- and trans-1-hydroxy-1-phenylquinolizidines

cis and trans-1-Hydroxy-1-phenylquinolizidines were prepared from 1-ketoquinolizidine and isolated by column chromatography. Infrared and nuclear magnetic spectral data were utilized for the elucidation of the structures.