Crystal and molecular structure of bis(aminomethylphosphonate)copper(II)

The crystal and molecular structure of bis(aminomethylphosphonate)-copper(II), C₂H₁₀N₂O₆P₂Cu, has been determined from MoK diffractometer data. The compound crystallizes in the monoclinic space groupP2₁/n witha =7.571(2),b = 4.943(1),c = 11.212(3) Å, = 105.84(2) °, andZ = 2. The structure was solved by the heavy-atom technique and refined by full-matrix least-squares methods toR = 0.041, using 1084 reflections for which ¦F _o¦ > 3.92 (¦F _o¦). In this complex, the Cu atom is square-planar coordinated by four O atoms from four phosphonic groups, and not by the amino group. The Cu-O bond lengths are 1.928(3) and 1.937(3) Å, and the phosphonic groups bridge adjacent Cu atoms in polymeric chains. The infrared spectrum of this complex is reported.     

Intermetallic compound formation at the In-Pd interface investigated with111In local probes

The TDPAC technique was applied to study the formation of In-Pd compounds in bilayer electrodeposited sample doped with the radioactive¹¹¹In. Subsequent isochronal annealings at increasing temperatures caused the Pd diffusion into the In layer reflected in the quadrupole interactionR(t) curves. The appearing new unique frequencies indicate the formation of ordered In₃Pd, In₃Pd₂ andInPd₂ phases in the sample. The identification of this In-Pd compounds was based on the PAC measurements for bulk In-Pd samples with defined stoichiometry.     

Extension of Bernstein's theorem for polynomial maps of complex Banach spaces

Bernstein's inequality (1) will be extended to polynomial maps of arbitrary complex Banach spaces; cf. (3). We also give conditions for equality in (3). The extension of Bernstein's inequality to the case of polynomial maps of ℂ into ℂ was given byTung [4] and [5].     

Local composition in binary mixtures of Lennard-Jones fluids with differing sizes of components

Three Lennard-Jones binary liquid mixture systems obeying Lorentz-Berthelot rules, but having differing component sizes and energy parameters, have been used to calculate the local fractions of the two components around each type of central particle over the entire composition range from molecular-dynamics data. It is found that well-defined local fractions can be determined even in the case where the size difference between the particles is large. The results obtained are compared with values predicted by the Wilson and NRTL equations. It is confirmed that the NRTL equation gives satisfactory agreement only in the case of mixtures of components having the same size parameters. A new correlation is proposed by a modification of the NRTL equation. This correlation can predict reasonably well local-fraction data for all the Lennard-Jones liquid mixtures studied so far.     

Polyester oligodiols by cationic AM copolymerization of L,L‐lactide and ε‐caprolactone initiated by diols

Cationic copolymerization of L,L ‐lactide (LA) and ε‐caprolactone (CL) initiated by low molecular weight diols in the presence of acid catalyst gives corresponding copolyesters terminated at both ends with hydroxyl groups in practically quantitative yield. Copolymerization proceeds by Activated Monomer mechanism. LA is consumed preferentially and at the later stages of copolymerization the reaction mixture is enriched with CL. In spite of that, random distribution of both units is observed and end‐groups are mainly ? LA‐OH groups and not ? CL‐OH groups. This is explained by the fact that to reach high conversion of both comonomers the relatively long reaction times are required and at those conditions transesterification reaction becomes significant. Thus the microstructure of copolymers and the nature of the end‐groups is governed by transesterification rather then by the kinetics of comonomers incorporation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3090–3097, 2007     

Composition of extraction products from alkylated high-sulphur coals

Products of reductive and non-reductive methylation of two high-sulphur coals (Mequinenza and Illinois No. 6) have been extracted by dichloromethane. It has been established that the efficiency of the transformation of coal to the products soluble in CH₂Cl₂ is higher for coals subjected to non-reductive methylation by the Liotta method than for those after reduction in the potassium/liquid ammonia system. The extracts and the extraction residues were subjected to elemental analysis, IR spectroscopy, and AP-TPR (Atmospheric Pressure-Temperature Programmed Reduction) measurements. It has been shown that the main species undergoing extraction by CH₂Cl₂ are aliphatic compounds or aromatic structures of low degree of condensation. The effect of the extraction on the sulphur groups in coal has been discussed.     

A simple pseudomolecular fluid in contact with a wall: Exact and approximate local densities

A simple model mimicking a molecular fluid, introduced by Labik, Nezbeda and Smith (J. Chem. Phys.80 (1984) 5219] is applied to calculations of density profiles of a molecular fluid in contact with a hard wall. This model provides a useful means of investigating many of the quantitative features of more realistic fluid-wall models. In this work we have computed the spherical harmonic coefficients both of the local densities and of the one-particle background correlation functions and have examined the rate of convergence of these expansions. Moreover, we have used this model to test the accuracy of the zeroth-order RAM perturbational theory for the local densityThis work was supported by CPBP, under the Grant No. 01.08.E 2.     

Endpoints of set-valued dynamical systems of asymptotic contractions of Meir–Keeler type and strict contractions in uniform spaces

In this paper, we introduce the concepts of the set-valued dynamical systems of asymptotic contractions of Meir–Keeler type and set-valued dynamical systems of strict contractions in uniform spaces and we present a method which is useful for establishing conditions guaranteeing the existence and uniqueness of endpoints of these contractions and the convergence to these endpoints of all generalized sequences of iterations of these contractions. The result, concerning the investigations of problems of the set-valued asymptotic fixed point theory, include some well-known results of Meir and Keeler, Kirk and Suzuki concerning the asymptotic fixed point theory of single-valued maps in metric spaces. The result, concerning set-valued strict contractions (in which the contractive coefficient is not constant), is different from the result of Yuan concerning the existence of endpoints of Tarafdar–Vyborny generalized contractions (in which the contractive coefficient is constant) in bounded metric spaces and provides some examples of Tarafdar–Yuan topological contractions in compact uniform spaces. Definitions and results presented here are new for set-valued dynamical systems in uniform, locally convex and metric spaces and even for single-valued maps. Examples show a fundamental difference between our results and the well-known ones.     

A chelate-forming resin prepared by the modification of anion-exchange resin amberlyst A-26 with thoron and its application

Summary A new chelate-forming resin was prepared from common anionexchanger Amberlyst A-26 and thoron. Thoron-loaded resin is stable and resistant to mineral acids. To differentiate the selectivity of thoron-loaded resin trien as competitive reagent was used. In the presence of trien thoron-loaded resin is almost selective for Fe(III) as a counter ion. The application of the resin to the analysis of iron in brass and the preconcentration and determination of iron in natural waters was described.     

Rotationally constrained Hartree-Fock calculations and nuclear fission

Static Hartree-Fock calculations for a model ${}^{144}\text{Nd}$ nucleus are carried out under the assumption of axial symmetry and with constraints on the component of angular momentum perpendicular to the symmetry axis. The resulting energy surfaces exhibit a well defined fission barrier which decreases with increasing angular momentum more rapidly than predicted by liquid drop calculations.