Valence band photoelectron spectra of platinum cyanides

Valence band X-ray photoelectron spectra of K₂[Pt(CN)₄]·3H₂O (1), K₂[Pt(CN)₄]Cl_0.3·xH₂O (2), and K₂[Pt(CN)₄Cl₂]·3H₂O (3), and the ultraviolet photoelectron spectrum of (2) have been recorded. These spectra imply that the binding energy of the highest occupied molecular orbital (HOMO) in (1) is greater than in (2). A band-like character for the HOMO of (2) with finite electron density at the Fermi level is consistent with this observation. The photoelectron spectra are correlated with the solid state electronic absorption spectra. Shifts in the K 3 binding energies are attributed to considerable differences in lattice site potentials between (1) and (2).     

FTIR spectra of (HF)2 and (HF)3 species in solid argon at 12K

Condensation of argon/HF mixtures at 12 K revealed sharp new 3825.5 and 3702.0 cm^?1 absorptions which exhibited different growth behaviour on sample warming. Mixed HF/DF samples revealed a single mixed isotopic satellite near the DF counterpart of the former band assigned to (HF)₂ and a group of satellites for the latter band assigned to (HF)₃.     

Cationic oligomerization and polymerization of some propenylbenzene derivatives

A comparative study was undertaken of the cationic oligomerization/polymerization of the natural propenylbenzene derivatives, anethole, isoeugenol, and isosafrole, together with synthetic o-methoxypropenylbenzene and N,N-dimethyl-p-propenylaniline using boron trifluoride diethyletherate as catalyst. Two (optimum) reaction temperatures were employed, ?12 and ?45°C, and only the (E) isomers of the monomers were studied. The order of reactivity of the monomers was found to be anethole > isoeugenol > isosafrole > o-methoxypronylbenzene as measured by following the rate of loss of monomer by proton magnetic resonance spectrometry at ?12°C. N,N-dimethyl-p-propenylaniline only appeared to form a complex with the catalyst. Low-molecularweight polymeric materials were prepared from anethole, isosafrole, and isoeugenol at ?45°C using the same catalyst while o-methoxypropenylbenzene formed oligomers. Isosafrole was recovered unchanged when treated with the boron trifluoride diethyl etherate initiator system at ?78°C in an attempt to increase the molecular weight of the polyisosafrole.     

Database and search techniques for two-dimensional gel protein data: a comparison of paradigms for exploratory data analysis and prospects for biological modeling

Two-dimensional (2-D) polyacrylamide gel electrophoresis can detect thousands of polypeptides, separating them by apparent molecular weight (Mr) and isoelectric point (pI). Thus it provides a more realistic and global view of cellular genetic expression than any other technique. This technique has been useful for finding sets of key proteins of biological significance. However, a typical experiment with more than a few gels often results in an unwiedly data management problem. In this paper, the GELLAB-II system is discussed with respect to how data reduction and exploratory data analysis can be aided by computer data management and statistical search techniques. By encoding the gel patterns in a "three-dimensional" (3-D) database, an exploratory data analysis can be carried out in an environment that might be called a "spread sheet for 2-D gel protein data". From such databases, complex parametric network models of protein expression during events such as differentiation might be constructed. For this, 2-D gel databases must be able to include data from other domains external to the gel itself. Because of the increasing complexity of such databases, new tools are required to help manage this complexity. Two such tools, object-oriented databases and expert-system rule-based analysis, are discussed in this context. Comparisons are made between GELLAB and other 2-D gel database analysis systems to illustrate some of the analysis paradigms common to these systems and where this technology may be heading.     

Infrared spectrum of Hg(OH)2 in solid neon and argon

Mercury(II) hydroxide molecules have been prepared upon mercury arc lamp irradiation of Hg, H(2), and O(2) mixtures in solid neon and argon. The strongest three infrared absorptions are identified through isotopic substitution (D(2), HD, (18)O(2), (16)O(18)O) and comparison to frequencies from DFT calculations. The isolated Hg(OH)(2) molecule is stable and has a linear O-Hg-O linkage in a C(2) structure with an 86 degrees dihedral angle. However, in aqueous solution Hg(2+) and 2OH(-) may form an Hg(OH)(2) intermediate, which eliminates water and precipitates solid HgO: The solid Hg(OH)(2) compound is not known.     

Vitamine

Analytical and Bioanalytical Chemistry -     

Similarities and differences in the structure of 3<Emphasis Type="Italic">d</Emphasis>-metal monocarbides and monoxides

The structure and properties of the monocarbides ScC, TiC, VC, CrC, MnC, FeC, CoC, NiC, CuC, ZnC and their negatively and positively charged ions together with 3 d-metal monoxide cations are calculated by density functional theory (DFT) and hybrid DFT methods. In addition to the spectroscopic constants, the computed properties include the electron affinities, ionization energies, and dissociation energies. These results along with our previous results for the neutral and negatively charged 3 d-metal monoxides allow a detailed comparison of similarity and differences in the bonding of the metal oxides and carbides. These results are compared with results obtained using other theoretical approaches and with experiment. Chemical bonding, analyzed using the natural bond orbital scheme, was found to be rather different in the 3 d-metal monocarbides and monoxides.     

Reactions of B atoms and clusters with NO: experimental and theoretical characterization of novel molecules containing B, N, and O

Reactions of boron atoms and clusters with NO molecules in solid argon have been studied using matrix isolation infrared absorption spectroscopy. The reaction products were identified by isotopic substitution ((10)B, (11)B, (15)N(16)O, (14)N(18)O, and mixtures) and comparison with density functional calculations of isotopic frequencies. In solid argon, boron atoms spontaneously reacted with NO to form the insertion molecule NBO. The BNBO and OBNNO molecules were formed by the B and NO addition reactions to NBO. The linear BBNO and BBBNO nitrosyls also were formed spontaneously on annealing. These molecules photochemically rearranged to the more stable BNBO and BNBBO isomers, which have linear polyyne-like structures. The photosensitive OBNNO molecule decomposed to form the NNBO(2) van der Waals complex. In addition, the novel OBON diradical was also formed on photolysis in high-concentration NO experiments.