Catalytic effects of transition metal (Co2+, Ni2+) complexes of N,N-bis(salicylaldehyde)-o-phenylenediimine (SOPD), N,N-bis(salicylaldehyde)-m-phenylenediimine (SMPD), and N,N-bis(salicylaldehyde)-p-phenylenediimine (SPPD), on the reduction of thionyl chloride at glassy carbon electrode, are evaluated by determining the kinetic parameters with cyclic voltammetric technique. The charge transfer process for the reduction of thionyl chloride is strongly affected by the concentration of the catalysts. Some quadridentate Schiff base-M(Ⅱ) complexes show sizable catalytic activities for the reduction of thionyl chloride. Catalytic effects of [M(Ⅱ)(SOPD)] complexes are slightly larger compared to [M(Ⅱ)2(SMPD)2] and [M(Ⅱ)2(SPPD)2] complexes. On those electrodes deposited with the catalysts, the observed exchange rate constants (ko) are in the range of 0.89-2.28 × 10-7 cm/s, while it is 1.24 × 10-7 cm/s on the bare glassy carbon electrode.

The rates of solvolysis of 1-(4-methoxyphenyl)-1-aryl-2,2,2-trifluoroethyl chlorides[I] in a variety of solvents were measured by an electroconductometric method. LArSR relationships (Yukawa-Tsuno eq.)were found to give a linear plot, log(k/ko)=-1.84[σo+0.918(σ+-σo)], in 80% aqueous ethanol. Small |ρ| and r values in comparison with 1-aryl-1-(trifluoromethyl)ethyl tosylate(ρ=-6.09, r=1.59) suggested that the carbocationic charge in the transition state was dispersed by a strong p-π donor, p-methoxy group. Linear mY plots with m 0.90 for all of the substituents in aqueous acetone and m=0.60-0.82 for those of aqueous ethanol indicate that this solvolysis proceeds via an SN1 mechanism with nucleophilic solvent assistance. Thiourea effects and isokinetic temperatures for the rate of solvolysis also can prove the above mechanism.

Second-order rate constants have been measured spectrophotometrically for the reaction of p-nitrophenyl acetate (PNPA) with morpholine, piperazine and piperidine in MeCN-H2O mixtures of varying compositions. The rate of the present aminolysis decreases upon additions of MeCN into H2O up to near 30-40 mole % MeCN and remains nearly constant upon further additions of MeCN. The reaction of PNPA with anionic nucleophiles, such as HO-, p-chlorophenoxide and butane-2,3-dione monoximate, has also exhibited two distinguishable reactivity zones. However, the reactivity trend for the anionic nucleophiles is quite different from the one obtained for the amine system, e.g. an initial rate decrease in the H2O-rich region followed by an increasing rate trend upon further additions of MeCN in the MeCN-rich region. The rate behaviors shown by the amine system in the MeCN-rich and by the anionic system in the H2O-rich region are unexpected based on the Hughes-Ingold rules. The present unusual rate trends have been attributed to changes in the solvent structure and pKa of the nucleophiles upon the addition of MeCN into H2O. The effect of solvent appears to be more significant for the TS than the GS, and the TS structure is considered to become tighter in the higher MeCN concentration.

Mastoparan B (MP-B) that is a novel MP isolated from the hornet Vespa basalis, was studied as compared with MP, in terms of interaction with phospholipid bilayer and antimicrobial activity. MP-B has more hydrophilic amino acid residues in hydrophilic face of amphiphilic α-helical structure than MP. The both peptides exhibited considerably different effect on interaction with lipid bilayers, e.g. their conformation in the presence of acidic and neutral liposomes, dye-release ability from encapsulated liposomes, but on the whole the interaction mode was similar. On antimicrobial activity, MP had a strong activity against Gram-positive bacteria but no against Gram negative ones. Contrary to this, MP-B had a strong activity against Gram-positive and potent against Gram-negative ones. Since both peptides have almost same residues on the hydrophobic side, such more hydrophilic surface on the molecule seems to lead to the subtle change in its interaction with membranes, resulting in the alternation in its biological activity.

A topological theory has been introduced to explain and evaluate the fractional volumes of system materials, the change of the weight and concentration of monomer molecules, molecular weight distribution, and interaction functions of polymer-polymer and polymer-oligomer, etc. for dispersion polymerization. The previous theory of Lu et al. has offered only an incomplete simulation model for dispersion polymer systems, whereas our present one gives a general theoretical model applicable to all the polymerization systems. The theory of Lu et al. considered only the physical property term caused by interaction between matters of low molecular weight (i.e., diluent, monomer, and oligomer) and polymer particles without dealing with physical properties caused by the structure of polymer networks in polymer particles, while our theory deals with all physical effect possible, caused by the displacement of not only entangled points but also junction points in polymer particles. The theoretically predictive values show good agreement with the experimental data for dispersion polymerization systems.

Nucleophilic substitution reactions of 1- and 2-naphthylethyl arenesulfonates, 2 and 3, with anilines and benzylamines in methanol at 65.0 ℃ are investigated. The rates are slower than those for the corresponding derivatives of 2-phenylethyl arenesulfonates, 1, which can be attributed to a greater degree of positive charge stabilization at Cα in the transition state (TS) by a greater electron supply from a phenyl ring compared to a naphthyl ring. The mechanism for the two naphthylethyl systems are similar to that for the 2-phenylethyl derivatives, except that the transition state is formed at somewhat an earlier position along the reaction coordinate. The secondary kinetic isotope effects involving deuterated nucleophilies indicate that naphthylethyl series are sterically more crowded in the TS than 2-phenylethyl system. The data in this work can not elucidate the possible participation of the aryl-assisted pathway in the reaction.

p-(2-Vinyloxyethoxy)benzylidenemalononitrile 2 and methyl p-(2-vinyloxyethoxy)benzylidenecyanoacetate 3 was prepared by the condensation of p-(2-vinyloxyethoxy)benzaldehyde 1 with malononitrile or methyl cyanoacetate, respectively. Vinyl ether monomers 2 and 3 polymerized quantitatively with radical initiators in γ-butyrolactone solution at 65 ℃. The trisubstituted terminal double bond participated in the vinyl polymerization and radical polymerization of 2 and 3 led to swelling polymers 4 and 5 that were not soluble in common solvents due to cross-linking. Under the same polymerization conditions ethylvinyl ether polymerized well with model compounds of p-methoxybenzylidenemalononitrile 6 and methyl p-methoxybenzylidenecyanoacetate 7, respectively, to give 1:1 alternating copolymers 8 and 9 in high yields. Polymers 4 and 5 showed a thermal stability up to 300 ℃ without any characteristic Tg peaks in DSC thermograms. Alternating copolymers 8 and 9 were soluble in common solvents such as acetone and DMSO, and the inherent viscosities of the polymers were in the range of 0.36-0.74 dL/g. Films cast from acetone solution were cloudy and tough and Tg values obtained from DSC thermograms were in the range of 59-60 ℃.

Flow properties of all suspensions are controlled by their flow units. The factors effecting on the flow units are the characteristics of the particle itself (surface properties, particle sizes, particle shapes and etc.), the electrostatic interactions among the particles and the influences of the medium in the suspensions. Here, we studied the transition between the flow units with shear rate which can be added to the above factors. For the concentrated starch-water suspensions, by using the Couette type rotational viscometer, we confirmed that at low shear rate, dilatancy is appeared, but it is transformed to thixotropy with increasing shear rate. In order to explain this fact, we derived the following flow equation, representing the transition from dilatancy to thixotropy with shear rate, by assuming the equilibrium between the flow units. f = X1β1s./α1 + 1/(1+Kexp(c0s.2/RT))((1-X1)/α2)sinh-1{(β2)0 s. exp(c2s.2/RT)} + K exp(c0s.2/RT)/(1+K exp(c0s.2/RT))((1-X1)/α3)sinh-1{(β3)0 s. exp(-c3s.2/RT)} By applying this flow equation to the experimental flow curves for the concentrated starch-water suspensions, the flow parameters were obtained. And, by substituting the obtained flow parameters to the flow equation, the theoretical flow curves were reproduced. Also, Ostwald curve was represented by applying the flow equation, and the applicability for stress relaxation was discussed.

Alkyl halides were reduced to the corresponding alkanes by the homonuclear bridging hydride, (μ-H)[(η5-MeCp)Mn(CO)2]2-PPN+ in THF at the elevated temperatures (40-60 ℃) under the pseudo first order reaction conditions where excess of alkyl halide was employed under nitrogen atmosphere. The reaction is of overall second order; first order with respect to [bridging hydride] and first order with respect to [alkyl halide] with the activation parameters, ΔH≠=28.93 kcal/mol and ΔS≠=17.95 e.u. The kinetic data, the ESR evidence and the reaction with cyclopropyl canbinyl bromide ensure that two possible reaction pathways are operable in this reaction: (1) concerted mechanism, and (2) single electron transfer pathway are in competition leading to the same product, the corresponding alkane.

Vanadium oxide-zirconia catalysts were prepared by dry impregnation of powdered Zr(OH)4 with aqueous solution of NH4VO3. The characterization of prepared catalysts was performed using 51V solid state NMR, XRD, and DSC. The addition of vanadium oxide up to 9 mol% to zirconia shifted the phase transitions of ZrO2 from amorphous to tetragonal toward higher temperatures due to the interaction between vanadium oxide and zirconia. On the basis of results of XRD and DSC, it is concluded that the content of V2O5 monolayer covering most of the available zirconia was 9 mol%. The crystalline V2O5 was observed only with the samples containing V2O5 content exceeding the formation of complete monolayer (9 mol%) on the surface of ZrO2.

Decay of the spin label attached to cytochrome c or to stearic acid has been measured by electron paramagnetic resonance (EPR) spectroscopy to monitor membrane oxidation induced by cytochrome c-membrane interaction. Binding of cytochrome c sequestered the acidic phospholipids and membrane oxidation was efficient in the order linoleic oleic>stearic acid for a fatty acid chain in the acidic phospholipids. The spin label on cyt c was destroyed at pH 7 whereas that on stearic acid embedded in the membrane was destroyed at pH 4, presumably due to different modes of cyt c-membrane interaction depending on pH. Interestingly, cyt c also interacts with phosphatidylethanolamine, an electrically neutral phospholipid, to cause rapid membrane oxidation. Both EPR and fluorescence measurements indicated that electrostatic interaction is at least partially responsible for the process.

The electrical conductivity of some phthalimide derivatives and their complexes with Co(II), Ni(II), Cu(II), or Zn(II) has been measured in the temperature range 290-435 K. Both the structure of phthalimide molecule and its complexes played an effective role in the conduction process. Conductometric titration and IR spectra were used to characterize the structure of studied samples.