Spectral, Magnetic, Electrical and Thermal Studies on Malonyl bis(thiosemicarbazide) Complexes

Mono- and binuclear complexes of malonyl bis(thiosemicarbazide), H₄ MBT, with VO²⁺, Co²⁺, Ni²⁺, Cu²⁺, Cd²⁺ and Pt⁴+ have been isolated. The elemental analyses, magnetic moments, spectra [u.v.–vis., i.r., e.s.r. (for Cu²⁺; VO²⁺) and mass], thermal and voltammetric measurements [for Co²⁺ and Ni²⁺] have been used to characterize the isolated complexes. The ligand behaves as binegative quadridentate with Cu²⁺, Co²⁺ and VO²⁺ ions, binegative pentadentate with Pt⁴+ and hexadentate, either as trinegative in [Cd₂(HMBT)(OC₂H₅)(C₂H₅OH)]H₂O or mononegative in [Ni₂(H₃MBT)(OAc)₃(C₂H₅OH)]. The lack of thiol and/or enol hydrogen during the complex formation was confirmed pH-metrically. The pK’s (10.70, 8.50 and 8.15) of H₄MBT reveal the removal of CSNH protons in one step and CONH in two steps. Also, the stability constants reveal a higher value for the Cu²⁺ complex and a lower one for VO²⁺. The TG analyses suggest high stability for most complexes followed by thermal decomposition in different steps. The kinetic and thermodynamic parameters for some decomposition steps in VO²⁺and Pt⁴⁺ thermograms have been calculated     

NMR studies of ionomers. 3. Synthesis and microstructure of poly(ethyl acrylate-co-lithium acrylate)

Copolymers of ethyl acrylate (EA) with lithium acrylate (LiA) with relatively low contents of LiA units (up to 30%) were synthesized by alkaline hydrolysis of poly(EA). ¹³C-NMR spectra of these copolymers registered in a mixture of deuterated benzene with deuterated methanol (85:15 v/v) presented configurational splittings of the ester methylene, methylene main chain, and ester carbonyl group signals. Assignments of these splittings were made and Bernoulli statistics with a meso probability of 0.48 could fit both poly(EA) and poly(EA-co-LiA). Only the C?O signal of the copolymer was sensitive to sequence distribution and indicated that the LiA units have a tendency to be isolated on the chain. Two-dimensional HETCOR pulse sequence helped to assign the main chain proton spectrum.     

Synthesis of vesicles on polymer template

Reactive single-tail cationic surfactants self-assemble on the anionic block copolymer templates. These systems spontaneously arrange in small vesicles of nanoscale size. The vesicles are further stabilized by dimerization of the assembled surfactant monomers forming double-tail surfactants bound to the block copolymer. The resulting systems are resistant to changes in environmental characteristics such as pH, ionic strength, and temperature variations. Hydrophilic macromolecules can be encapsulated in the internal aqueous volume of these vesicles. The simplicity of the preparation makes these systems promising as drug and gene delivery carriers.     

Metal complexes of 2-acetylpyridine N(4)-dihexyl- and N(4)-dicyclohexylthiosemicarbazones

Summary 2-Acetylpyridine N(4)-dihexyl- and N(4)-dicyclohexylthiosemicarbazone, HAc4DHex and HAc4DCHex, respectively, and Fe^III, Co^II, Co^III, Ni^II, Cu^II and Zn^II complexes have been prepared and characterized by molar conductivities, magnetic susceptibilities and spectroscopic techniques. For many of the complexes, loss of the N(2)H hydrogen occurs, and the ligands coordinate to the metal centres as NNS monoanionic, tridentate ligands, e.g., [M(NNS)X] (M = Co^II, Ni^II, Cu^II, NNS = Ac4DHex or Ac4DCHex and X = Cl or Br), [Fe(NNS)₂]ClO₄, [Co(NNS)₂]BF₄, [Cu(NNS)NO₃] and [Zn(NNS)OAc]. Zn^II ion is also chelated by neutral ligands in [Zn(HNNS)X₂] (X = Cl, Br). In addition, [Ni(Ac4DHex)-(HAc4DHex)]X (X = BF₄, ClO₄) and [Ni(HAc4DCHex)₂]-(BF₄)₂ are reported where the neutral thiosemicarbazone is coordinated via the pyridyl nitrogen, azomethine nitrogen and thione sulfur. Crystal structure determinations of HAc4DCHex and [Cu(Ac4DHex)Br] show the former to contain the bifurcated hydrogen bonded form and the latter to be planar with no significant interaction between neighbouring centres.     

Synthesis of New Reagent Benzyloxybenzaldehydethiosemicarbazone (BBTSC): Selective,Sensitive and Extractive Spectrophotometric Determination of Pd(II) in Water Samples and Synthetic Mixtures

A new reagent, benzyloxybenzaldehydethiosemicarbazone (BBTSC) was synthesized and a new method was developed for the simple, highly selective and extractive spectrophotometric determination of palladium(II) with BBTSC at wave length 365 nm. The metal ion formed a yellow colored complex with BBTSC in acetate buffer of pH 5.0, which was easily extractable into cyclohexanol with 1:1 (Metal: Ligand) composition. The method obeys Beer's law in the range of 5–60 ppm. The molar absorptivity and Sandell's sensitivity were found to be 0.4 × 10⁴ Lt. mol^?1 cm^?1 and 0.02661 μg cm^?2, respectively. The correlation co‐efficient of the Pd(II)‐BBTSC complex was 0.9657, which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD) (n = 10), which was 0.321% and its detection limit 0.016875 μg.mL^?1. The instability constant of the method was calculated by Asmus' method as 3.5714 × 10^?4. The interfering effect of various cations and anions were also studied. The proposed method was successfully applied for the determination of palladium(II) in synthetic and water samples. The results were compared with those obtained using an atomic absorption spectrophotometer, testing the validity of the method.     

A recourse certainty equivalent for decisions under uncertainty

We propose a new criterion fordecision-making under uncertainty. The criterion is based on acertainty equivalent (CE) of a (monetary valued) random variable Z, $$S_\upsilon (Z) = \mathop {\sup }\limits_z \{ z + E_Z \upsilon (Z - z)\} ,$$ wherev(·) is the decision maker'svalue-risk function. This CE is derived from considerations ofstochastic optimization with recourse, and is calledrecourse certainty equivalent (RCE). We study (i) the properties of the RCE, (ii) the recoverability ofv(·) fromS _v (·) (in terms of the rate of change in risk), (iii) comparison with the “classical CE”u ^?1 Eu(·) inexpected utility (EU) theory, (iv) relation to risk-aversion, (v) connection with Machina'sgeneralized expected utility theory, and its use to explain theAllais paradox and other decision theoretic paradoxes, and (vi) applications to models ofproduction under price uncertainty, investment in risky and safe assets andinsurance. In these models the RCE gives intuitively appealing answers forall risk-averse decision makers, unlike the EU model which gives only partial answers, and requires, in addition to risk-aversion, also assumptions on the so-calledArrow-Pratt indices.     

Synthesis and nonlinear optical properties of polyester containing 4‐di‐(2′‐hydroxyethoxy)‐4‐diphenyl‐hydrazonomethyl chromophore

The nonlinear optical property of new polyester has been studied via second harmonic generation (SHG). The values of electro‐optic coefficients, d₃₃ and d₃₁, of the poled polymer film were 3.15 × 10 ^?7 and 1.5 × 10^?7 esu, respectively. Thermal behavior of this polyester was studied through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). 4‐di‐(2′‐hydroxyethoxy)‐4‐diphenyl‐hydrazonomethyl was synthesized from the reaction of 3,4‐dihydroxy‐4‐diphenyl‐hydrazonomethyl with 2–chloro–1‐ethanol in a 1:2 mole ratio and subsequently reacted with terephthaloyl chloride (TPC) in the presence of pyridine, as catalyst, to produce the new nonlinear polyester. The chemical structures of the resulting monomers and polymer were characterized by CHN analysis, ¹H‐NMR, FT‐IR, and UV–Vis spectroscopy. Copyright © 2009 John Wiley & Sons, Ltd.     

The geometry of solvability and duality in linear programming

Solvability and boundedness criteria for dual linear programming problems are given in terms of the problem data and the intersections of the nonnegative orthant with certain complementary orthogonal subspaces. This research was partly supported by the Office of Naval Research, contract Nonr-1228(10), project NR 047-021, and by the National Science Foundation, project G-14102.