Conversion of 3-benzoyl-1-methyl-4-phenyl-γ-piperidol by arylamines and arylhydrazines. Synthesis of 3-arylamino-1-oxo-1-phenylpropanes and 1,3-diarylpyrazoles and their fragmentation under electron impact

It has been established that on heating, 3-benzoyl-4-hydroxy-1-methyl-4-phenylpiperidine is ring-opened in the presence of arylamines by a type of retroaldol reaction, with subsequent transamination of the intermediate Mannich base and the formation of 3-arylamino-1-oxo-1-phenylpropanes. When using arylhydrazines this γ-piperidol is recyclized with the formation of 1,3-diarylpyrazoles and their 4,5-dihydro derivatives. The mass spectral behavior of a series of 3-arylamino-substituted 1-phenylpropanones has been studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1486–1495, October, 2007.     

The Effect of Alkane Chain Length on the Liquid–Liquid Critical Temperatures of Oligostyrene/Linear-Alkane Mixtures

Summary. Upper critical solution temperatures (UCSTs) for liquid–liquid demixing in a set of mixtures of linear alkanes (pentane (N ₁=5) to pentacontane (N ₁=50)) with an oligostyrene (1241amu, N ₂=12) are reported. We find strong correlation between the Hildebrand solubility parameters of the alkanes and the UCST. Correlations are developed which enable predictions concerning the miscibility of mixtures of compounds with longer chains.     

Initial oxidation and hydroxylation of the Ge(100)-2 x 1 surface by water and hydrogen peroxide

We use density functional theory to investigate the surface chemistry of initial oxidation and hydroxylation of the Ge(100)-2 x 1 surface by water and hydrogen peroxide. Comparison of the reaction of water on the Si(100)-2 x 1 and Ge(100)-2 x 1 surfaces shows that the kinetics of oxidation of the Ge(100)-2 x 1 surface with water is slower. Our calculations also show that oxidation products on the Ge(100)-2 x 1 surface are less thermodynamically stable than on Si. We also investigate two competing dissociation reactions of H2O2 on the Ge(100)-2 x 1 surface. We find that dissociative adsorption via cleavage of the OH bond is less exothermic than OO dissociation. Furthermore, interdimer OO dissociation has a lower activation barrier than interdimer or intradimer OH dissociation, although interdimer dissociation products are found to be less stable compared than those formed from intradimer dissociation reactions. Finally, we find that the oxidation products formed from hydrogen peroxide are more stable than those formed from water.     

The mass spectra of (trimethylstannyl)x methanes: Occurrence of tin-carbon double bonds

The mass spectra of (Me₃Sn)_nCH_4?n, where n varies from 1 to 4, (Me₃Sn)₂CClX, where X equals H, Cl, Br or I, together with some tetraalkyltin compounds and Me₃SnCCl₃, are presented. Comparisons with mass spectra of the silicon analogs¹ show a large number of similarities, including the appearance of allylic ions which require Group IV metal to carbon π-bonding. Multiple rearrangements are observed with the halogenated tin compounds which bring the α-halogen into direct bonding with the tin atom.     

Experiments in Solving Mixed Integer Programming Problems on a Small Array of Transputers

The time-consuming process of solving large-scale Mixed Integer Programming problems using the branch-and-bound technique can be speeded up by introducing a degree of parallelism into the basic algorithm. This paper describes the development and implementation of a parallel branch-and-bound algorithm created by adapting a commercial MIP solver. Inherent in the design of this software are certain ad hoc methods, the use of which are necessary in the effective solution of real problems. The extent to which these ad hoc methods can successfully be transferred to a parallel environment, in this case an array of at most nine transputers, is discussed. Computational results on a variety of real integer programming problems are reported.     

Effect of film thickness on the electro-reduction of molecular oxygen on electropolymerized cobalt tetra-aminophthalocyanine films

We studied the electrocatalytic activity of cobalt tetra-aminophthalocyanine (CoTAPc) for the reduction of molecular oxygen (O₂) on adsorbed monomeric and on electropolymerized films of different thicknesses on glassy carbon (GC) electrode. The polymeric films, denoted poly-CoTAPc, were first characterized by electrochemical impedance spectroscopy and it appears that the types of phenomena revealed to be occurring depend less on the film thickness in basic than in acid media. For O₂ reduction, the results showed that poly-CoTAPc is more active than the monomeric CoTAPc adsorbed on GC. Indeed, rotating ring-disk electrode data showed that polymeric CoTAPc promotes the four-electron reduction of O₂ to water in parallel to a two-electron reduction to give peroxide. On monomeric and thin films of poly-CoTAPc, a two-electron reduction mechanism predominates. In basic media the activity increases very slightly with thickness, whereas in acid media this increase is more pronounced. This parallels the observed behavior revealed by electrochemical impedance spectroscopy.     

Sorption of uranium by non-living water hyacinth roots

Summary Many studies have shown that water hyacinth (Eichhornia crassipes) roots can be used to accumulate high concentrations of organic as well as inorganic pollutants. They are currently used to remediate aquatic environments and aqueous solutions. In the present study, sorption of uranium from aqueous solutions by using dried roots of water hyacinth has been investigated. The sorption of uranium was examined as a function of initial concentration, pH, weight of roots and contact time. Five different concentrations 20, 40, 60, 80, and 100 μg ^. ml^-1 were used. Sorption proves to be very rapid and depend on pH, weight of roots and concentration of uranium. Maximum sorption capacity of water hyacinth roots was 64,000 U⁶⁺ μg/g. The sorption of uranium by water hyacinth roots follows a Langmuir isotherm.     

A Theoretical Study of Complex Formation between Formaldehyde and Lithium

Ab initio SCF and CI calculations on the cationic and neutral complexes of formaldehyde and lithium are reported. For the cationic complex CH₂O/Li⁺, the stabilization energy of 41.7 kcal/mol obtained from the SCF calculation increases to 51.6 kcal/mol if a configuration interaction is introduced. For the neutral complex CH₂O^?/Li⁺, the C_2v-conformer of the ²A₁-state with the equilibrium bond distances of d(C? O) = 1.23 Å and d (O? Li) = 1.90 Å is calculated to be more stable than the ₂B₁-state with d (C? O) = 1.34 Å, and d (O? Li) = 1.65 Å. Charge transfer and polarization effects upon complex formation are discussed.     

Stabilization of γ‘ phase in Bi<Subscript>4</Subscript>V<Subscript>2-x</Subscript>Fe<Subscript>x</Subscript><Superscript>II</Superscript>O<Subscript>11-1.5x</Subscript> series

Summary This work reports the room-temperature stabilization of the Bi₄V_2-xFe_x^IIO_11-1.5x γ ‘ phase, a promising ionic conductive material that finds application in solid oxide fuel cell and oxygen sensor devices. The Fe(II) cation proved to be a better stabilizer than Fe(III), which was previously used, since a lower substitution degree of V⁵⁺ is needed for the former. Powder X-ray diffraction, Fourier-transform infrared spectroscopy and differential scanning calorimetry were used in these experiments.     

Isomeric Schiff bases related by dual imino‐group reversals

Two isomeric pairs of Schiff bases, N,N′‐bis­(2‐methoxy­benzyl­idene)‐p‐phenyl­enediamine, C₂₂H₂₀N₂O₂, (I), and 2,2′‐dimeth­oxy‐N,N‐(p‐phenyl­enedimethyl­ene)dianiline, C₂₂H₂₀N₂O₂, (II), and (E,E)‐1,4‐bis­(3‐iodo­phen­yl)‐2,3‐diaza­buta‐1,3‐diene (alternative name: 3‐iodo­benzaldehyde azine), C₁₄H₁₀I₂N₂, (III), and N,N′‐bis­(3‐iodo­phen­yl)ethylenedi­imine, C₁₄H₁₀I₂N₂ [JAYFEV; Cho, Moore & Wilson (2005). Acta Cryst. E 61 , o3773–o3774], differ pairwise only in the orientation of their imino linkages and in all four individual cases occupy inversion centers in the crystal, yet all four compounds are found to assume unique packing arrangements. Compounds (I) and (II) differ substantially in mol­ecular conformation, possessing angles between their ring planes of 12.10 (15) and 46.29 (9)°, respectively. Compound (III) and JAYFEV are similar to each other in conformation, with angles between their imino linkages and benzene rings of 11.57 (15) and 7.4 (3)°, respectively. The crystal structures are distinguished from each other by different packing motifs involving the functional groups. Inter­molecular contacts between meth­oxy groups define an R₂²(6) motif in (I) but a C(3) motif in (II). Inter­molecular contacts are of the I⋯I type in (III), but they are of the N⋯I type in JAYFEV.