Module character amenability of Banach algebras

In this paper we introduce the notion of module character amenable Banach algebras and show that they possess module character virtual (approximate) diagonals. As a basic example, we show that for an inverse semigroup S with the set of idempotents E, the semigroup algebra ? ¹(S) is module character amenable as an ? ¹(E)-module if only if S is amenable.     

Oxidative addition of MeI to some cyclometalated organoplatinum(II) complexes: Kinetics and mechanism

New cyclometalated platinum(II) complexes [PtMe(C^N)L], 1, in which C^N = deprotonated 2-phenylpyridine (ppy), benzo[h]quinoline (bhq) or 2-(p-tolyl)pyridine (tpy) and L = PPh₃ or PMePh₂, were synthesized by the reaction of [PtMe(C^N)(SMe₂)] with 1 equiv of L. The reaction of complexes 1 with MeI gave the cyclometalated Pt(IV) complexes [PtMe₂I(C^N)L], 3. On the basis of kinetic studies, using Uv–visible spectroscopy, it was suggested that the latter oxidative addition reactions were proceeded by an S_N2 mechanism. The rates of the reactions at different temperatures were measured and consistent with the proposed mechanism, large negative ΔS³ values were found for each reaction. Besides, rate of reactions (in CHCl₃) involving the PPh₃ complexes [PtMe(C^N)(PPh₃)], were almost 3–5 times slower than those involving the PMePh₂ complexes [PtMe(C^N)(PMePh₂)]. This was attributed to the electronic and steric effects of PPh₃ ligand as compared with that of PMePh₂ ligand which was further confirmed using density functional theory (DFT) calculations through finding approximate structures for the described complexes.     

Synthesis and Characterization of Single-Phase Cubic ZrO2 Spherical Nanocrystals by Decomposition Route

A simple thermal decomposition route has been developed to prepare single-phase cubic ZrO₂ nanospheres by [Zr(sal)₃(H₂O)₂](NO₃) as the new precursor. The ZrO₂ nanocrystals have been prepared by bis-aqua, tris-salicylaldehydato zirconium(IV) nitrate; [Zr(sal)₃(H₂O)₂](NO₃), as precursor in oleylamine (C₁₈H₃₇N) and triphenylphosphine (C₁₈H₁₅P). To control the particle size, combination of C₁₈H₃₇N and C₁₈H₁₅P were applied as surfactants. The C₁₈H₃₇N and C₁₈H₁₅P play an important role in preventing aggregation of ZrO₂ nanocrystals. The products were characterized by X-ray diffraction, transmission electron microscopy, photoluminescence spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy to depict the phase and morphology. The FT-IR spectrum showed the purity of obtained ZrO₂ nanocrystals with cubic phase.     

Measurement of στ product of solid state laser materials by an alternative method: Application to Nd3+ doped YVO4 crystal for 4 F 3/2→4 I 11/2 transition

In this paper an alternative approach for measurement of στ product for ⁴ F _3/2→⁴ I _11/2 transition of Nd³⁺ doped YVO₄ crystal is reported. In this method a microchip laser is formed by keeping a small piece of the sample in plane-plane resonator and a diode laser (808 nm) is used for pumping. The pump power induced thermal lensing effect is used to make the cavity stable. The cavity mode area is estimated by measuring the thermal lens focal length at the threshold and the average pump area is measured by Gaussian fit to the intensity profiles of the pump beam. The value of στ product of Nd:YVO₄ crystal obtained by this method is within 10% of the reported values. The advantage of this method is that it is a simple method for direct measurement of στ product of laser crystals.     

Trapping of Terminal Platinapolyynes by Copper(I) Catalyzed Click Cycloadditions; Probes of Labile Intermediates in Syntheses of Complexes with Extended sp Carbon Chains,and Crystallographic Studies

The silylated hexatriynyl complex trans-(C₆F₅)(p-tol₃P)₂Pt(C≡C)₃SiEt₃ ( PtC₆TES ) is converted in situ to PtC₆H (wet n-Bu₄N⁺ F⁻, THF) and cross coupled with the diyne H(C≡C)₂SiEt₃ ( HC₄TES ; CuCl/TMEDA, O₂) to give PtC₁₀TES (71 %). This sequence is repeated twice to afford PtC₁₄TES (65 %) and then PtC₁₈TES (27 %). An analogous series of reactions starting with PtC₈TES gives PtC₁₂TES (60 %), then PtC₁₆TES (43 %), and then PtC₂₀TES (17 %). Similar cross couplings with H(C≡C)₂Si(i-Pr)₃ ( HC₄TIPS ) give PtC₁₂TIPS (68 %), PtC₁₄TIPS (68 %), and PtC₁₆TIPS (34 %). The trialkylsilyl species (up to PtC₁₈TES ) are converted to 3+2 “click” cycloadducts or 1,4-disubstituted 1,2,3-triazoles trans-(C₆F₅)(p-tol₃P)₂Pt(C≡C)_n-1C=CHN(CH₂C₆H₅)N=N (29–92 % after workups). The most general procedure involves generating the terminal polyynes PtC _x H (wet n-Bu₄N⁺ F⁻, THF) in the presence of benzyl azide in DMF and aqueous CuSO₄/ascorbic acid. All of the preceding complexes are crystallographically characterized and the structural and spectroscopic properties analyzed as a function of chain length. Two pseudopolymorphs of PtC₂₀TES are obtained, both of which feature molecules with parallel sp carbon chains in a pairwise head/tail packing motif with extensive sp/sp van der Waals contacts.     

<Superscript>68</Superscript>Ga-radiolabeled magnetic nanoparticles for PET–MRI imaging

In this study, magnetic multimodal nanoparticles with potential applications in magnetic- and nuclear-medicine imaging, magnetic resonance imaging, hyperthermia, and theranostic (therapeutic and diagnostic), applications were prepared by coating iron oxide nanoparticles with silica (core–shell), functionalizing with aminopropyltriethoxy silane and coupling with diethylenetriamine pentaacetic acid ligand (DTPA). Radiolabeling of core–shell–DTPA particles with ⁶⁸Ga radiometal was carried out through chelation of ⁶⁸Ga(III) ions by DTPA and was used for positron emission tomography. The biodistribution of the ⁶⁸Ga-radiolabeled magnetic nanoparticles compared to free ⁶⁸Ga(III) was checked in normal Balb/c mice up to 2 h.     

Cauliflower‐like NiCo2O4−Zn/Al Layered Double Hydroxide Nanocomposite as an Efficient Electrochemical Sensing Platform for Selective Pyridoxine Detection

In the present study, a cauliflower‐like NiCo₂O₄?Zn/Al layered double hydroxide (NiCo₂O₄?Zn/Al LDH) nanocomposite was used as a novel electrode material for the sensitive and selective determination of pyridoxine (vitamin B₆). The structure and morphology of the as‐prepared nanocomposite were characterized by X‐ray diffraction (XRD), FT‐IR, field emission scanning electron microscopy (FESEM) and energy dispersive X‐ray spectroscopy (EDX). The NiCo₂O₄?Zn/Al LDH nanocomposite exhibited excellent electrocatalytic ability in the oxidation of pyridoxine, which could result from the synergistic effect of the two components. The developed sensor also provided a selective determination of pyridoxine in the presence of other species such as vitamins (B₁, B₂, B₁₂ and ascorbic acid), inorganic ions and biomolecules. The fabricated sensor showed a good linear response for pyridoxine over the concentration ranges 2×10^?7–2.0×10^?4 mol L^?1 with a low detection limit of 8.6×10^?8 mol L^?1. Finally, the proposed method was successfully applied for the determination of pyridoxine in commercial tablets and plasma samples with satisfactory results. Furthermore, this novel sensor displayed superior benefits in terms of stability, sensitivity, repeatability and cost. The present work aims to expand NiCo₂O₄ based nanocomposites to sensor fields and promote the development of pyridoxine sensors.     

Complex formation of hydronium ion with several crown ethers in 1,2-dichloroethane,acetonitrile, and nitrobenzene solutions

A conductance study concerning the interaction between hydronium ion and several crown ethers in acetonitrile, nitrobenzene and 1,2-dichloroethane solutions has been carried out at 25°C. The stability constants of the resulting 1:1 complexes in acetonitrile and nitrobenzene solutions were determined from the molar conductance-mole ratio data and found to vary in the order 18C6>DB30C10>DC18C6>DB18C6>DB21C7>DB24C8>B15C5. In 1,2-dichloroethane solution, the complexation process results in the dissociation of ion pairs. There is an inverse relationship between the stabilities of the complexes and the Gutmann donicity of the solvents. In nitrobenzene solution, some evidence for the formation of a 2:1 sandwich adduct between the smaller crowns (i.e., B15C5 and 18-crowns) are observed from the molar conductance-mole ratio data which is supported by the¹H NMR data.     

Coated-wire copper(II)-selective electrode based on phenylglyoxal-α-monoxime ionophore

A copper(II) ion-selective electrode based on a recently synthesized 2-quinolyl-2-phenylglyoxal-2-oxime (phenylglyoxal-alpha-monoxime) has been developed. The PVC-based membrane containing phenylglyoxal-alpha-monoxime, dibutyl phthalate as plasticizer, and sodium tetraphenylborate as anion excluder and membrane modifier, was directly coated on the surface of a platinum-wire electrode. The response of the electrode was linear with a near-Nernstian slope of 28.2 mV decade(-1) within the Cu2+ ion concentration range 1x10(-6)-1x10(-1) mol x L(-1). The response time for the proposed electrode to achieve a 95% steady potential for Cu2+ concentrations ranging from 1x10(-1) to 1x10(-6) mol x L(-1) is between 10 and 50 s, and the electrode is suitable for use within the pH range of 3 to 6.5. The electrode has a detection limit of 5x10(-7) mol x L(-1) Cu2+ and its selectivity relative to several alkali, alkaline earth, transition, and heavy metal ions was good. The coated-wire electrode could be used for at least two months without a considerable alteration of its potential. Applications of the electrode for determination of copper in milk powder samples and as an indicator electrode for potentiometric titration of Cu2+ ion using EDTA are reported.