Hyperfine structure measurements in the 7S3 metastable finestructure level in stable and unstable Eu+ isotopes

Clouds of stable and unstable Eu⁺ isotopes have been confined in a Paul trap, each containing about 10⁵ particles. In a microwave-optical double resonance experiment several hyperfine separations in the 4f⁷ 6s ⁷S₃ exited level have been measured with the experimental uncertainties ranging between 10^-8 and 3×10^-6. These experiments have confirmed that also in the case of an excited level with a large number of hyperfine or Zeeman sublevels the microwave-optical double resonance technique in a Paul trap can be useful for precise hyperfine structure investigation. The hyperfine coupling constants A and B have been determined for the isotopes ¹⁵³Eu⁺, ¹⁵¹Eu⁺, ¹⁵⁰Eu⁺ and ¹⁴⁸Eu⁺. The results complement earlier measurements on the ground state of Eu⁺ and give additional information on the hyperfine anomaly in the Eu isotopic chain.     

Synthesis and Computational Study of Phosphorus Ionic Liquids

The synthesis of six tetraalkylammonium bromopentachlorophosphoride ionic liquids (ILs) is reported here. Their structures were determined by IR, ¹H NMR, and ¹³C NMR spectroscopy. Moreover, thermogravimetric (TG) and differential thermal analysis (DTA) were used to investigate the thermal behavior of these compounds. The results show that these ILs have excellent thermal stability below 145°C, and by decreasing the size of the alkyl groups, the thermal stabilities will increase. Along with the experimental study, these compounds have been studied computationally at the B3LYP/LANL2DZ level of theory using the PC GAMESS/Firefly program package. From these calculations, optimized geometries, molecular parameters, and vibrational spectra of ILs have been calculated. In addition, calculated frequencies are compared with the experimental frequencies after correction by the appropriate scaling factor. This comparison shows that our theoretical data are in good agreement with the experimental results.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis and Characterization of Some New Zinc(II) Complexes Incorporating Heterocyclic Thiophosphates as a Ligand

New tetracoordinated complexes of Zn (II) have been synthesized by the reaction between zinc chloride and 3-methyl-2-benzothiazolylidenamido-thiophosphoryl dichloride (L₁), (3-methyl-2-benzothiazolylidenamido)-bis-(diethylamido)thiophosphate (L₂), 3-benzyl-2-benzothiazolylidenamido thiophosphoryl dichloride (L₃), and (3-benzyl-2-benzothiazolylidenamido)-bis-(diethyl-amido) thiophosphate (L₄) in a 1:1 ratio. The complexes have been isolated and characterized by elemental analysis, electrical conductivity, and mass and IR spectral studies. The stability constants of these complexes also have been determined in aqueous solution by spectrophotometric methods.     

Synthesis and Characterization of Hg(II) Complexes with 2-Subsituted Benzothiazole Thiophosphates

Some complexes of 3-methyl-2-benzothiazolylidenamido thiophosphoryl dichloride (L₁), (3-methyl-2-benzothiazolylidenamido)–bis-(diethylamido) thiophosphate (L₂), 3-benzyl-2-benzothiazolylidenamido thiophosphoryl dichloride (L₃), and (3-benzyl-2-benzothiazolylidenamido)–bis-(diethylamido) thiophosphate (L₄) have been synthesized by a reaction with mercuric chloride in a 1:1 ratio. The complexes have been characterized by elemental analysis, electrical conductivity, and mass and IR spectral studies. The stability constants of these complexes have also been determined by a spectrophotometric technique and compared with zinc complexes of the previously discussed ligands.     

Synthesis,characterization, and antimicrobial activity of palladium(II) and platinum(II) complexes with 2‐substituted benzoxazole ligands

The synthesis and antimicrobial activity of palladium(II) and platinum(II) complexes derived from heterocyclic bidentate ligands, namely 2‐(2′‐aminophenyl)benzoxazole [L¹H₂], 2‐(2′‐hydroxyphenyl)benzoxazole [L²H], and 2‐(2′‐mercaptophenyl)benzoxazole [L³H], are reported here. These complexes have been characterized by elemental analyses, molecular weight determinations, conductance measurements, infrared, ¹H NMR, and electronic spectral studies. The resulting colored complexes are monomeric in nature. On the basis of above‐described studies, square‐planar geometry has been suggested for the resulting complexes. The ligands and their metal complexes were tested against certain microorganisms to assess their antimicrobial properties. The results indicate that the metal complexes are found more active than the parent ligands. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:44–50, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20578     

Single molecule conductance of porphyrin wires with ultralow attenuation

A series of thioacetate-terminated butadiyne-linked porphyrin oligomers have been synthesized with one to three porphyrin repeat units. Single molecule electrical scanning tunneling microscopy measurements using the I(s) and I(t) methods were used to determine the molecule conductances for this series of oligomers. The molecular conductance shows an exponential falloff with sulfur-sulfur distance with a remarkably low attenuation factor of beta = (0.04 +/- 0.006) A-1.     

Synthesis of biologically active phenoxy derivatives of substituted benzothiazole organophosphates

The reaction of S‐(phenyl benzothiazolyl‐2)phosphorodichloridothioate/phosphorodichloridodithioate with 2 mol of phenol/4‐chlorophenol/4‐nitrophenol in the presence of stoichiometric amounts of triethylamine in dry THF/CH₂Cl₂ has afforded a series of the corresponding organophosphate phenoxy derivatives ( 1a , 1b , 2a , 2b , and 3a , 3b ). Plausible structures have been proposed on the basis of elemental analysis, IR, ¹H NMR, ³¹P NMR, and mass spectral studies. The antibacterial activity of these organophosphate phenoxy derivatives has been evaluated against pathogenic bacteria Staphylococcus aureus (+ve) and Escherichia coli (−ve). The antifungal activity of these organophosphate phenoxy derivatives has been evaluated against pathogenic fungi Aspergillus niger and Fusarium oxysporium. The results indicate that organophosphate phenoxy derivatives are found more active than the parent compounds. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:84–88, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20582     

Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by differential absorption spectrometry with the direct Zeeman effect

A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions (¹⁹⁶Hg, ¹⁹⁸Hg, ²⁰²Hg, ²⁰⁴Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope ²⁰⁴Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m³ for benzene) level, the interference from SO₂, NO₂, O₃, H₂S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m³ at 1 s averaging and 0.1 mg/m³ at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified.     

Physicochemical aspects of <Emphasis Type="Italic">Trichosporon cutaneum</Emphasis> CCY 30-5-10 adhesion and biofilm formation potential on cellophane

This paper focuses on the adhesion and biofilm formation potential of cellulolytic yeast Trichosporon cutaneum CCY 30-5-10 on solid cellophane from a novel perspective. First, physicochemical characterisation of the cells and carrier (cellophane) was performed to evaluate the effect of different culture media (complex vs mineral) on yeast cell adhesion. (Un)favourable adhesion conditions were predicted using the thermodynamic approach. Next, the ability of the cells to colonise the carrier under the above conditions was quantified and the biofilm structure was characterised using image analysis. The approaches described were found suitable to predict and experimentally verify favourable (cell-solid) adhesion, i.e. the hydrophobic and low electron-donor nature of cellophane together with hydrophobic cells (obtained when cultivated in a complex culture medium) were found to have a major impact in defining successful yeast adhesion with subsequent biofilm formation.     

Synthesis and Biocidal Activity of Organophosphates Derived from Benzothiazole

The synthesis, biocidal activity, and spectroscopic data of a new series of S-phosphorylated/thiophosphorylated derivatives of 2-(2′-mercaptophenyl) benzothiazole are reported in this study. Derivatives were prepared by reacting 2-(2′-mercaptophenyl) benzothiazole with phosphorus oxychloride/phosphorus thiochloride in different molar ratios [1:1, 2:1, 3:1]. All of the derivatives were found to be antifungal agents with less toxicity than the standard Dithane M-45.