Deep Mourning for Dr. Yang Shixian Dr. Yang Shixian A Life of Dedication

Dr.Yang Shixian(Shao-tseng Yang),the Editor-in-chief of the Chemical Journalpassed away on February 19,1985,was a well-renowned Chinese educationa-list and chemist.He was deputy to the first five Sessions of the National People’sCongress,member of the Standing Committee of the Fifth and Sixth Sessions of theChinese Poeple’s Political Consultative Conference,member of the Academic Councilof the Chinese Academy of Sciences,director and then honorary director     

Potentiometric determination of the formation constants for complexes of 3,2′,2″-triaminopropyldiethylamine with cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II)

The tripodal tetraamine ligand N{(CH₂)₃NH₂}{(CH₂)₂NH₂}₂ (pee), has been investigated as an asymmetrical tetraamine chelating agent for Co^II, Ni^II, Cu^II, Zn^II and Cd^II. The protonation constants for this ligand and the formation constants for its complexes have been determined potentiometrically in 0.1 M KCl at 25 °C. The successive protonation constants (log K _n ) are: 10.22, 9.51, 8.78 and 1.60 (n = 1–4). One complex with formula M(pee)²⁺ (M = Co, Ni, Cu, Zn and Cd) is common to all five metal ions and the formation constant (log _ML) is: 12.15, 14.17, 16.55, 13.35 or 9.74, respectively. In addition to the simple complexes, Co^II, Cu^II and Zn^II also give hydroxo complexes, and Cu^II and Ni^II give complexes with monoprotonated pee. [Zn(pee)](ClO₄)₂ and [Cd(pee)Cl](ClO₄) complexes were isolated and are believed to have tetrahedral and trigonal-bipyramidal structures, respectively.     

Polylactones. 13. Transesterification of Poly(L-Lactide) with Poly(Glycoude), Poly(β-Propio-Lactone), and Poly[ε -Caprolactone)

Homogeneous blends of poly(L-lactide) (M _n = 30 000 to 40 000) and poly(β-propiolactone) or poly(ε-caprolactone) were prepared in solution. The solvent-free blends were subjected to transesterification catalyzed by means of methyl triflate, triflic acid, boron trifluoride, or tributyltin methoxide at 100 or 150°C. At 100°C, transesterification was barely detectable even after 96 h. When poly(β-propiolactone) was used as the reactant at 150°C, degradation was faster than transesterification regardless of the catalyst. The same negative result was obtained for heterogeneous blends of poly(L-lactide) and poly(glycolide). In the case of poly(ε-caprolactone), copolyesters with slightly blocky sequences were obtained with tributyltin methoxide as catalyst, whereas the acidic catalysts caused rapid degradation. The copolyesters were characterized by means of ¹H-NMR spectroscopy with regard to their molar composition, by means of ¹³C-NMR spectroscopy with regard to their sequences, and by means of differential scanning calorimetry with regard to crystallinity.     

Comment on “Thermodynamic and isotherm studies of the biosorption of Cu(II), Pb(II), and Zn(II) by leaves of saltbush (Atriplex canescens)”

Recently, Sawalha et al. [M.F. Sawalha, J.R. Peralta-Videa, J. Romero-Gonzalez, M. Duarte-Gardea, J.L. Gardea-Torresdey, J. Chem. Thermodyn. 39 (3) (2007) 488–492] presented characterisation of the biosoption of Cu(II), Pb(II), and Zn(II) onto the saltbush leaves (Atriplex canescens) at 297 K and pH 5.0. However, the model application and some thermodynamic calculations were problematic or erroneous.     

Complexation of the zinc(II) ion with 2,2′-bipyridine and 1,10-phenanthroline in 4-methylpyridine and solvation structure of the manganese(II), cobalt(II), nickel(II), and zinc(II) ions in 4-methylpyridine and 3-methylpyridine

Complexation of the zinc(II) ion with 2,2-bipyridine (bpy) and 1,10-phenanthroline (phen) has been calorimetrically studied in 4-methylpyridine (4Me-py) containing 0.1 mol dm^–3 (n-C₄H₉)₄NClO₄ as a constant ionic medium at 25°C. The formation of [ZnL]²⁺, [ZnL₂]²⁺, and [ZnL₃]²⁺ (L=bpy, phen), and their formation constants, reaction enthalpies and entropies were determined. Our EXAFS (extended X-ray absorption fine structure) measurements showed that the solvation structure of the manganese(II), cobalt(II), and nickel(II) ions is six-coordinate octahedral in 4Me-py and 3-methylpyridine (3Me-py), while that of the zinc(II) ion is four-coordinate tetrahedral in 4Me-py. Since [ZnL₃]²⁺ is expected to have an octahedral structure, a tetrahedral-to-octahedral structural change should take place at a certain step of complexation. The thermodynamic parameters, especially reaction entropies, indicate that the structural change occurs at the formation of [Zn(bpy)₂]²⁺ and [Zn(phen)]²⁺.     

Molecular dynamics simulations for CO(2) absorption spectra. I. Line broadening and the far wing of the ν(3) infrared band

Classical molecular dynamics simulations (CMDS) have been carried out for gaseous CO(2) starting from the intermolecular potential energy surface. Through calculations for a large number of molecules treated as rigid rotors, various autocorrelation functions (ACFs) are obtained together with probabilities of rotational changes. Those used in the present paper are the ACFs of the center of mass velocity and of the molecular orientation, and the conditional probability of a change of the angular speed. They enable calculations, respectively, of the mass diffusion coefficient, of the infrared (dipolar) band shape including the wings, and of individual line-broadening coefficients. It is shown that these calculations, free of any adjustable parameter, lead to good agreement with measured values. This is expected from previous studies for the mass diffusion coefficient and line-broadening coefficients, but it is, to our knowledge, the first demonstration of the interest of CMDS for the prediction of band wings. The present results thus open promising perspectives for the theoretical treatment of the difficult problem of far wings profiles.     

Coordination Polymers. IV. Physicochemical Studies on Chelate Polymers of Cr(III), Mn(II), Fe(II), Co(II), Ni(II), and Cu(II) with a Schiff Base of 4,4′-(4,4′-Biphenylylene Bisazo)di-(salicylaldehyde) with m. Toluidine

Coordination polymers of Cr(III), Mn(II), Fe(II), Co(II), Ni(II), and Cu(II) with a Schiff base derived from 4,4′ - (4,4′ -biphenylylene bisazo) di (salicylaldehyde) and m-toluidine have been prepared. All the polychelates are dark colored and insoluble in common organic solvents. Magnetic susceptibility and electronic and IR spectra of the polychelates have been studied. All the polychelates except Cu(II) show octahedral structures while Cu(II) polychelate is suggested to be a square planar.     

Synthesis and Characterization of Dipeptide Schiff Base Complexes of Copper(Ⅱ), Zinc(Ⅱ), Nickel(Ⅱ) and Cobalt(Ⅱ)

N-saliCylidenchnoacidcomplexesInayserveasmodelsfOrN-bodoXylidenedoacidcomp1exSystmschcharebelieVedtObetheintermediatesinthetranboIlationprocessl'l.ThecoordinaionOfametaJiontosuchSchiffbasesstabilizestheazomethine1inkag,underconditionsthatwouldothendsepromotebondcleaVag[2-5].Inaddition,thecomplexesOftalnoeddScAfbasesareconsideredtobeanewldndOfpoentialanhbactrialandanhcanceragentsl6].However,littleattentionhasbeengiventoSystemsinwhchtheScusbasesarederivedfromsimPlepePtides.ThispoprrePO…