Effective, fast, and low temperature encapsulation of fullerene derivatives in single wall carbon nanotubes

High filling of single wall nanotubes (SWCNTs) with the typical exohedrally functionalized fullerene derivative of C₆₀N-methyl-3,4-fulleropyrrolidine C₆₀-C₃NH₇ is reported at the temperature of refluxing hexane. The new peapod material is characterized by STM (scanning tunneling microscopy), TEM (transmission electron microscopy) and Raman spectroscopy. Atomically resolved STM scans on SWCNT show no excessive defects or sidewall functionalization as a result of this treatment. The radial breathing mode (RBM) mode of SWCNT at 165 cm⁻¹ becomes weaker and shifted to 169 cm⁻¹ indicating filled nanotubes. TEM studies show bundles of SWCNT are highly filled with derivative C₆₀-C₃NH₇ and form the (C₆₀-C₃NH₇)_n peapods. Individual pyrrolidine-type functional groups attached to the fullerene cages are unambiguously visualized by a lower-dose observation.     

The Klein correspondence of line congruences immersed in an elliptic spaceS 3 onto the hyperquadricP 4

This article is devoted to the investigation and the construction of the Klein correspondence of line congruences referred to a specialized moving frame in a 3-dimensional elliptic spaceS ₃ to the hyperquadricP ⁴ of the Klein 5-dimensional elliptic spaceS ₅. The Klein correspondence is given and characterized by Theorems 1, 2. The methods adapted here are based on Cartan's differential calculus [1], [6].     

Analytical $$\boldsymbol{\alpha}\boldsymbol{+}\boldsymbol{\alpha}$$ Potential for Energy Range between 6 and 280 MeV

Physics of Atomic Nuclei - In this work we derive analytically a real $$\alpha+\alpha$$ potential using the JLM effective nucleon–nucleon (NN) interaction. The aim is to obtain analytically...     

Synthesis and structural investigation of mono- and polynuclear copper complexes of 4-ethyl-1-(pyridin-2-yl) thiosemicarbazide

The reaction between 2-hydrazinopyridine and ethylisothiocyanate produced 4-ethyl-1-(pyridin-2-yl) thiosemicarbazide (HEPTS). Its reaction with copper fluoride, chloride, bromide, acetate, nitrate, perchlorate, sulfate, carbonate, hydroxide and copper metal produced 15 Cu(II) complexes. The copper metal is easily oxidized in aqueous-ethanol solution of HEPTS giving [Cu(2)(EPTS)(H(2)O)(3)(OH)(3)]EtOH. Different complexes for the same anion were synthesized by controlling the heating time. Characterization by elemental, thermal, magnetic and spectral (electronic, IR, mass and ESR) studies showed the formation of mono-, di-, tri- and tetra nuclear complexes. The room temperature solid state ESR spectra of the complexes show an axial spectrum with d(x)(2)-y(2) ground state, suggesting distorted tetragonal geometry around Cu(II) center. The kinetic and thermodynamic parameters for the different decomposition steps in the complexes were calculated. HEPTS and its Cu(II) complexes showed high activity against gram negative bacteria; [Cu(3)(EPTS)(2)(EtOH)(2)Br(4)] has more activity.     

Cloud point extraction and spectrophotometric determination of Cu(II) in saturated saline solutions using 4-ethyl-1-(pyridin-2-yl)thiosemicarbazide

4-Ethyl-1-(pyridin-2-yl)thiosemicarbazide (HEPTS) has been used as a new complexing agent in cloud point extraction (CPE) for preconcentration and determination of trace amounts of copper in saturated saline medium. The chemical variables affecting the separation and determination processes were optimized. Copper(II) is preconcentrated using 0.05% (w/v) Triton X-114 and 10⁻⁴ M HEPTS at pH 6. The surfactant rich phase containing the complex was dissolved in 2 mL MeOH and determined spectrophotometrically. The calibration curve is linear in the 0.1–25 ng/mL copper range. The proposed method was applied successfully in the determination of copper in water and saturated saline samples. The reaction between CuSO₄ and HEPTS yields a deep-blue solid complex which is characterized by analytical and spectroscopic analyses.     

Templating Ag on DNA/polymer hybrid nanowires: Control of the metal growth morphology using functional monomers

Ag nanowires and nanoparticles have been formed on hybrid λ-DNA/conducting polymer templates. The strong, but non-covalent, interaction of the conducting polymer with the double helix allowed us to incorporate chemical functionalities (alkynyl) into the DNA/conducting polymer strands by synthesis of functional monomers. Oxidative polymerisation of alkynyl-thienylpyrrole in the presence of λ-DNA produced conductive nanowires bearing alkyne groups; we show, using a combination of AFM, cAFM and EFM phase measurements that the alkyne functionality strong influences the subsequent templating reaction of Tollens’ reagent to produce uniform conductive nanowires comprised of many connected Ag clusters.     

Corrigendum of “Similarity analysis in magnetohydrodynamics: Hall effects on free convection flow and mass transfer past a semi-infinite vertical flat plate” [International Journal of Non-Linear Mechanics 38 (2003) 513–520]

The problem of steady, laminar mixed convection heat and mass transfer past a semi-infinite vertical plate in the presence of Hall current has been studied. The governing partial differential equations describing the problem are transformed to a system of non-linear ordinary differential equations with appropriate boundary conditions using Lie's method of infinitesimal transformation groups. The non-linear ordinary differential equations are solved numerically using Chebyshev spectral method. The effects of various parameters on the velocity profiles, temperature and concentration profiles are presented and discussed. This work is an extension and correction for the paper by Megahed et al. [1], published in International Journal of Non-Linear Mechanics 38 (2003) 513–520.     

Utility of (p‐Sulfonamidophenyl)azomalononitrile,and Ethyl Acetoacetate in Synthesis of Fused Azole and Azines Derivatives II

[(p‐Sulfonamidophenyl)azo]malononitrile ( 1a,b ) reacted with N‐cyclohexanemethylidene‐2‐cyanoacetohydrazide, N'‐arylmethylidene‐2‐cyanoacetohydrazide ( 3a‐c ), S‐methylthiourea and hydrazine hydrate to afford [1,2,4]triazolo‐[1,5‐a]pyridinone derivatives ( 2a,b ) & ( 4a‐c ), substituted pyrimidines 5a,b and 6a,b. The corresponding pyridazinones 7a,b were synthesized from the reaction of 1c,d with ethyl cyanoacetate. Compound 7a,b reacted with elemental sulfur to yield 8a,b . Compound 6a underwent cycloaddition with α‐cinnamonitrile 9a‐e to yield 11a‐c, 14 and 15 . Also, compound 6a reacted with β‐ketoester and 1,3‐diketones to give 16, 17 and 18 .     

Fatty acid hydrazides in heterocyclic synthesis: Synthesis of 1,2‐diazepine and pyridazine derivatives

1,2‐Diazepinone derivatives 6a–d, 8a,b, and 10a–c were synthesized from the reaction of olefines carrying EWG as ethoxymethylene malononitrile, ethoxymethylene cyanoacetate, and tetracyanoethylene with 1a–f respectively. Also, 5‐alkyl‐6‐oxotetrahydropyridazine‐4,4‐dicarboxylate derivatives 12a–c were afforded via the reaction of 1d–f with diethyl ethoxymethylene malonate. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:259–264, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20294