Phosphonitrilic Chloride. XXXVIII. Study of Electrical Conductivity of Diisothiocyanophosphazene Polymer and Hexaisothiocyanocyclotriphosphazene

The electrical conductivity of hexaisothiocyanocyclotriphos-phazene NsPs(NCS)₆ and linear diisothiocyanophosphazene polymer (NP(NCS)₂)n was determined. It was found that hexaisothiocyanocyclotriphosphazene is ionic and linear diiso-thiocyanocyclotriphosphazene polymer has predominantly electron conductivity.     

Effect of the Conformation of Polymer Chain on the Reduction Rate of Polyacrylatopentaamminecobalt(III) by Polymer-Bound Ferrous Chelates and the Excited State of Tris(Bipyridine)Ruthenium(Ii)

Electron transfer reactions of Co(NH₃)₅PAA (PAA = polyacrylic acid) with either the polyanionic polymer-bound ferrous chelate, Fe¹¹P-SS (P-SS = vinylbenzylaminediacetate-co-styrenesulfonate) or the uncharged polymer-bound ferrous chelate, Fe¹¹P-VPRo (P-VPRo = vinylbenzylaminediacetate-co-vinylpyrrolidone), and the Ru(bpy)²⁺ ₃ photosensitized reduction of Co(NH₃)₅PAA have been investigated in aqueous solutions at pH 5.4, I = 0.06 (I is ionic strength), and 25°C. For the ferrous chelate reductions, the second-order rate constants for Fe¹¹-PSS and Fe¹¹P-VPRo were almost equal to that for the corresponding nonpolymer-bound ferrous chelate, Fe¹¹BDA (BDA = benzylaminediacetate). The results indicate that there is no appreciable steric hindrance due to the polymer chains of the polymer-bound ferrous chelates and that the effect of columbic repulsion force between the polyanion chains can be ignored for the reaction of Co(NH₃)₅PAA with Fe¹¹P-SS. The results also suggest that there are two kinds of the pendant Co(III) species, “reactive” and “inert.” The inert Co(III) species are shielded by the polymer chains from attack of the Fe(II) chelates that are present in the bulk solutions. A similar reaction behavior was observed in the Ru(bpy)²⁺ ₃ photosensitized reduction of Co(NH₃)₅PAA at pH 5.4. For the Co(III) complex having an extremely few Co(III) complex moieties on the polymer chain, almost all of the Co(III) groups were hardly reduced by the excited state of Ru(bpy)²⁺ ₃, and reverse quenching occurred due to binding of the Ru(bpy)²⁺ ₃ to the polyacrylic acid chain of the polymer complex. On the other hand, for Co(NH₃)₅PAA with a relatively large number of the Co(III) moieties on the polymer chain, lifetime measurements at a higher concentration of the Ru(bpy)²⁺ ₃ showed a double-exponential fit, which suggests that there are two parallel decay processes. The fast and slow components mainly correspond to the decays: Ru(bpy)²⁺ ₃ quenched by Co(III) and reverse quenching due to binding of Ru(bpy)²⁺ ₃ into the compact polymer chains.     

Simultaneous determination of testosterone, cortisol, and dehydroepiandrosterone in saliva by stable isotope dilution on-line in-tube solid-phase microextraction coupled with liquid chromatography–tandem mass spectrometry

We have developed a simple and sensitive method for the simultaneous determination of testosterone (TES), cortisol (CRT), and dehydroepiandrosterone (DHEA) in saliva by automated online in-tube solid-phase microextraction (SPME) coupled with liquid chromatography–tandem mass spectrometry (LC–MS/MS) using a Discovery HS F5 column. The optimum in-tube SPME conditions were 25 draw/eject cycles of 40 μL of sample at a flow rate of 200 μL/min using a Supel-Q PLOT capillary column as an extraction device. The extracted compounds were easily desorbed from the capillary by passage of the mobile phase, and no carryover was observed. The in-tube SPME LC–MS/MS method showed good linearity with correlation coefficients r?≥?0.9998 for TES, CRT, and DHEA using their respective stable isotope-labeled internal standards. The intra-day and inter-day precisions (relative standard deviations) were below 4.9 and 8.5 % (n?=?5), respectively. This method was successfully utilized to analyze TES, CRT, and DHEA in saliva samples without any other pretreatment or interference peaks, and the quantification limits (S/N?=?10) of TES, CRT and DHEA were about 0.01, 0.03 and 0.29 ng/mL saliva, respectively. The recoveries of these compounds spiked into saliva samples were each above 94 %. This method was applied to analyze changes in salivary TES, CRT, and DHEA levels resulting from stress and fatigue load.     

Convenient synthesis of glycosyl bromide from 1-O-acetyl sugars by photo-irradiative phase-vanishing reaction of molecular bromine

The synthesis of glycosyl bromides from 1-O-acetyl sugars using a photo-irradiative phase-vanishing method involving molecular bromine was achieved. A bottom phase of molecular bromine was overlaid first with perfluorohexanes (FC-72), followed by overlaying with ethyl acetate containing a 1-O-acetyl sugar. Upon irradiation, the bromine layer gradually disappeared, leaving two phases. Glycosyl bromide was obtained in good yield from the ethyl acetate phase.     

Application of 28Mg for characterization of Mg uptake in rice seedling under different pH conditions

The magnesium (Mg) uptake of rice seedlings treated with different pH solutions was investigated using tracer of ²⁸Mg. The application of ²⁸Mg enabled the determination of Mg uptake amount within 15 min of the different pH treatments. The uptake amount of ²⁸Mg and its distribution in rice plants were determined by using the imaging plate. The result demonstrated that the Mg uptake amount was approximately 3 μmol/15 min per plant in 0.27 mM Mg solution at pH 5.6, and this uptake decreased by 30 % at lower pH conditions (pH 4.5). On the contrary, the pH 6.5 condition induced the Mg uptake activity to 4.4 μmol/15 min. The inverse relationship found between proton concentration in nutrient solution and the Mg uptake amount within 15 min of treatment demonstrated that the low pH condition could inhibit the Mg uptake activity as a consequence of the competition between Mg²⁺ and proton. It is concluded that under low pH conditions, regardless of other factors, there is a decrease of Mg uptake activity in rice roots.     

Ni‐Catalyzed [4+3+2] Cycloaddition of Ethyl Cyclopropylideneacetate and Dienynes: Scope and Mechanistic Insights

A detailed study of the Ni‐catalyzed [4+3+2] cycloaddition reaction between ethyl cyclopropylideneacetate and dienynes has been conducted, resulting in the development of a new method for the synthesis of compounds containing nine‐membered rings. We studied the reactivity of various dienynes, together with their substituent and conformational effects. The mechanism of the reaction was probed by examining the stoichiometric reactions of the Ni complexes and dienynes.     

Synthesis,Structure, and Reactivity of Lewis Base Stabilized Plumbacyclopentadienylidenes

Plumbacyclopentadienylidenes, in which the lead atoms have divalent states and are coordinated by THF, pyridine and N‐heterocyclic carbene, were synthesized and characterized. The THF‐ and pyridine‐stabilized compounds can be regarded as rare examples of hypervalent 10‐X‐4 species. The equilibrium between the THF adduct and the free plumbacyclopentadienylidene was evidenced by spectroscopic analysis and theoretical calculations. The THF adduct in benzene converted into a plumbylene dimer, where one of the lead centers is coordinated by THF and the other lead atom is coordinated by a divalent lead atom, the dimer gradually decomposing into spiroplumbole. The THF adduct unexpectedly reacted with trifluoroborane and trichlorogallane to afford fluoroborole and chlorogallole, which are the first examples of non‐annulated fluoroborole and gallole, respectively.     

Effects of carboxyl-group counter-ions on biodegradation behaviors of TEMPO-oxidized cellulose fibers and nanofibril films

The biodegradation behaviors of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized cellulose fibers (TOCs) and TEMPO-oxidized cellulose nanofibril (TOCN) films containing various carboxyl-group counter-ions were studied. Na⁺, H⁺, Ca²⁺, NH₄ ⁺, Cu²⁺, K⁺, and Cs⁺ were introduced into the TOCs or TOCN films, by ion-exchange treatment, as the carboxyl-group counter-ions. TOCs suspended in distilled water were treated with a commercial crude cellulase, and the TOCN films were subjected to soil burial tests. The crude-cellulase-treated products obtained from the TOCs were separated into water/ethanol-insoluble and -soluble fractions, i.e., high- and low-molecular-weight fractions, respectively. The degradation behaviors of the TOCs were evaluated from the weight recovery ratios of the water/ethanol-insoluble fractions and their viscosity-average degrees of polymerization. The results showed that the degradation behaviors of the TOCs were greatly influenced by the counter ion, and the counter-ion order of degradability was Na⁺ ≈ NH₄ ⁺ ≈ K⁺ ≈ Cs⁺ ? Ca²⁺ > H⁺ > Cu²⁺. These degradability differences were influenced by the swelling behavior of the corresponding TOCs in distilled water; the higher the swelling degree of the TOC, the higher the degradation efficiency of the TOC in the reaction with crude cellulase. Similar biodegradation behaviors were observed in soil burial tests for TOCN films containing various carboxyl-group counter-ions in soil burial test; again the counter ion greatly influenced the resultant biodegradability. The biodegradation behaviors of TOCs and TOCN films can therefore be controlled by selecting an appropriate carboxyl-group counter-ion.     

On the ‐boundedness of solution operator families of the generalized Stokes resolvent problem in an infinite layer

In this paper, we prove the ‐boundedness of solution operator families of the generalized Stokes resolvent problem in an infinite layer with resolvent parameter , where , and our boundary conditions are nonhomogeneous Neumann on upper boundary and Dirichlet on lower boundary. We want to emphasize that we can choose 0 < ? < π ∕ 2 and γ₀ > 0 arbitrarily, although usual parabolic theorem tells us that we must choose a large γ₀ > 0 for given 0 < ? < π ∕ 2. We also prove the maximal L_p ? L_q regularity theorem of the nonstationary Stokes problem as an application of the ‐boundedness. The key of our approach is to apply several technical lemmas to the exact solution formulas of a resolvent problem. The formulas are obtained through the solutions of the ODEs, in the Fourier space, driven by the partial Fourier transform with respect to tangential space variable . Copyright © 2014 John Wiley & Sons, Ltd.