Coordination chemistry of chelating nitrogen ligands with tungsten carbonyl nitriles

The reactions of a series of Schiff base ligands (1–4) prepared by condensation of pyridine-2-carboxaldehyde and 2-X-anilines (X = F, Cl, Br, OMe) with W(CO)₃(RCN)₃ results in the formation of deeply coloured complexes W(CO)₃(1–4)(NCR) which readily react with carbon monoxide to afford W(CO)₄(1–4). The ligand 5, prepared from pyridine-2-carboxaldehyde and N,N-dimethylethylenediamine, coordinates to W(CO)₃ through the conjugated pyridine—imine chelate to afford complexes with a pendant dimethylamino group which reacts with electrophiles. Of the ligands studied, only the bis-amine, pyridine ligand 8, coordinates to W(CO)₃ in a tridentate manner. These reactions provide insight into the geometric and electronic factors which influence coordination of nitrogen containing ligands at a fac-tricarbonyl metal centre.     

THE EVIDENCE OF DECONFINEMENT PHASE TRANSITION OF SU(2) LATTICE GAUGE MODEL BY MONTE CARLO METHOD

In this paper,we have calculated the SU(2) lattice gauge by the Monte Carlo method.For the finite temperature problem 8³×4 lattice is used and for the zero temperature problem 8⁴ lattice.From the calculations of the energy density,heat capacity and entropy density,the results indicate that there is a deconfinement phase transition when T/Λ_L=40—50.     

Surfactant adsorption at the salt/water interface: comparing the conformation and interfacial water structure for selected surfactants

We report in situ spectroscopic measurements monitoring the adsorption of a series of carboxylate surfactants onto the surface of the semisoluble, ionic solid fluorite (CaF2). We employ the surface-specific technique, vibrational sum-frequency spectroscopy (VSFS), to examine the effect that surfactant adsorption has on the bonding interactions and orientation of interfacial water molecules through the alteration of the electric properties in the interfacial region. In addition, we report on the chain length and headgroup dependence of the formation of hydrophobic self-assembled monolayers on the surface of the solid phase. Differences in chain length and headgroup functionality lead to large changes in the adsorption behavior and structuring of the monolayers formed and the interactions of interfacial water molecules with these monolayers. Fundamental studies such as these are essential for understanding the mechanisms involved in the surfactant adsorption process, information that is important for industrially relevant processes such as mineral ore flotation, waste processing, and petroleum recovery.     

Arbeiten mit Nesslers Reagens

Ohne Zusammenfassung     

Ueber die Destillation von Formaldehyd

Ohne Zusammenfassung     

DIRECT SIMULATION OF DEEP INELASTIC SCATTERING OF HEAVY-IONS (I) ONE PARAMETER DISTRIBUTION

The distributions of dynamic variables in the deep inelastic scattering (DIS) of heavy-ions are studied by a direct simulation technique based on the single-nucleon-transfer-mechanism. The relative motion of the two collision partners is described by a Lagrange equation, and the transition probability of a single nucleon during the interaction time is calculated by the statisti-cal spectroscopy method.The occurrence of the transition event and the corresponding change of the dynamic variables are both treated randomly according to the transition probability. The calculated results for the reaction of ⁴⁰Ar+⁵⁸Ni(E_L=280MeV) are compared with experimental data.