Copper(I) complexes of heterocyclic thiourea ligands

The coordination of heterocyclic thiourea ligands (L = N-(2-pyridyl)-N′-phenylthiourea (1), N-(2-pyridyl)-N′-methylthiourea (2), N-(3-pyridyl)-N′-phenylthiourea (3), N-(3-pyridyl)-N′-methylthiourea (4), N-(4-pyridyl)-N′-phenylthiourea (5), N-(2-pyrimidyl)-N′-phenylthiourea (6), N-(2-pyrimidyl)-N′-methylthiourea (7), N-(2-thiazolyl)-N′-methylthiourea (8), N-(2-benzothiazolyl)-N′-methylthiourea (9), N,N′-bis(2-pyridyl)thiourea (10) and N,N′-bis(3-pyridyl)thiourea (11)) with CuX (X = Cl, Br, I, NO₃) has been investigated. CuX:L product stoichiometries of 1:1–1:5 were found, with 1:1 being most common. X-ray structures of four 3-coordinate mononuclear CuXL₂ complexes (CuCl(6)₂, CuCl(7)₂, CuBr(6)₂, and CuBr(9)₂) are reported. In contrast, CuBr(1)₂ is a 1D sulfur-bridged polymer. CuIL structures (L = 7, 8) are 1D chains with corner-sharing Cu₂(μ-I)₂ and Cu₂(μ-S)₂ units, and CuCl(10) is a 2D network having μ-Cl and N-/S-bridging L. Two [CuL₂]NO₃ structures are reported: a mononuclear 4-coordinate copper complex with chelating ligands (L = 10) and a 1D link-chain with N-/S-bridging L (L = 3). Two ligand oxidative cyclizations were encountered during crystallization. CuI crystallized with 6 to produce zigzag ladder polymer [(CuI)₂(12)]·½CH₃CN (12 = N-(pyrimidin-2-yl)benzo[d]thiazol-2-amine) and CuNO₃ crystallized with 10 to form [Cu₂(NO₃)(13)₂(MeCN)]NO₃ (13 = dipyridyltetraazathiapentalene).     

The study of quadrupole hyperfine interactions in pionic atoms of181Ta and165Ho

Conclusion In Table 3 we have listed the Q values of¹⁶⁵Ho and¹⁸¹Ta obtained by the pionic methods from this experiment and the one from Ebersoldet. al. and also the results by the muonic methods.^{4, 5} They are all in good agreements within the experimental uncertainties around 1%. The large discrepency between the Q values of¹⁸¹Ta from Ref. 5 and Ref. 7 was discussed and explained in detail in Ref. 5.The _o obtained in¹⁶⁵Ho is comparable to the _o calculated by using the Kisslinger's potential. However, the experimental _o for¹⁸¹Ta from this experiment is 28% larger than the theoretical value by Scheck³ by using the perturbation method.As it was mentioned at the beginning of this paper that the strong interaction quadrupole effect introduces characteristic level broadening to each components of the multiplet. The excellent fit between the calculated composite curve with the observed experimental h.f.s. spectra could be obtained only by varying all three independent parameters Q_eff, _o and _o. Without _o, or ₂, no satisfactory fitting could be obtained. That this illustrates the intrigue strong quadrupole effects on each components of a multiplet do behave as predicted by Scheck.³     

Mass and magnetic moment of the antiproton by the exotic atom method

Precision determinations of the mass and magnetic moment of the antiproton were made by the exotic atom method. Antiprotons were stopped in lead or uranium targets. De-excitation X-rays from the antiprotonic atoms were viewed by a high resolution Ge (Li) detector. Six principal transitions of the p?Pb spectrum (16 → 15 to 11 → 10) were analyzed to deduce a value of the antiproton mass. The fine structure splittings of the 11 → 10 and 12 → 11 transitions of p?Pb and p?U were used to determine a value of the antiproton magnetic moment. Our computed values of the energy eigenvalues of the (n, l, j) levels included corrections due to vacuum polarization and higher order radiative terms, electron screening, nuclear finite size and nuclear polarization. In the case of the p?U data, an additional shift due to the dynamic E2 mixing of nuclear rotational levels with antiprotonic orbital levels was included. Noncircular transitions were included in the analysis of the data. The values obtained for the antiproton mass and magnetic moment, 938.179±0.058 MeV and ? 2.791±0.021 nuclear magnetons, respectively, are compared with the corresponding quantities pertaining to the proton, 938.2796 ± 0.0027 MeV and +2.793 nuclear magnetons, respectively (error 1.1 × 10^?6 nuclear magnetons).     

Laser intracavity absorption: A numerical and experimental study with a pulsed dye laser

A flash pumped dye laser (Rh6G+Methanol) has been used to study the intra-cavity absorption of I₂ vapour over a wide range of extinctions and over a selected range of laser energies. A computer model based on the characteristics of the experimental laser provides values for quantitative comparison with the experimental ones. Reasonable agreement exists between the numerical computations and the experimental findings.     

Separation of dietary omega‐3 and omega‐6 fatty acids in food by capillary electrophoresis

A lower dietary omega‐6/omega‐3 (n‐6/n‐3) fatty acid ratio (<4) has been shown to be beneficial in preventing a number of chronic illnesses. Interest exists in developing more rapid and sensitive analytical methods for profiling fatty acid levels in foods. An aqueous CE method was developed for the simultaneous determination of 15 n‐3 and n‐6 relevant fatty acids. The effect of pH and concentration of buffer, type and concentration of organic modifier, and additive on the separation was investigated in order to determine the best conditions for the analysis. Baseline separations of the 15 fatty acids were achieved using 40 mM borate buffer at pH 9.50 containing 50 mM SDS, 10 mM β‐cyclodextrin, and 10% acetonitrile. The developed CE method has LODs of <5 mg/L and good linearity (R² > 0.980) for all fatty acids studied. The proposed method was successfully applied to the determination of n‐3 and n‐6 fatty acids in flax seed, Udo® oils and a selection of grass‐fed and grain‐fed beef muscle samples.     

Indolalkaloide aus Conopharyngia durissima STAPF. 134. Mitteilung über Alkaloide [1]

The alkaloids akuammiline ( 1 ) and anhydrovobasindiol ( 6 ) were isolated from the trunk bark of the Apocynacea Conopharyngia durissima STAPF . The structure of the unknown base anhydrovobasindiol was elucidated and this base was partially synthetised from the alkaloid vobasine. The well-known akuammiline could be correlated by LiAlH₄ reduction to picralinol ( 4 ).     

有机硅活性中间体的研究 II. 一些含环丙基的有机硅化合物的合成及其结构

用锂有机物的方法合成了四种含有环丙基有机硅化合物,对上述每种化合物中可能存在着的立体异构进行了分离和和构型测定。     

Ion-pair high-performance liquid chromatography of diaminopimelic acid in hydrolysates of physiological samples.

A method is reported for the determination of diaminopimelic acid (DAPA) in physiological samples. DAPA is derivatized with an o-phthaldialdehyde reagent solution, subjected to reversed-phase high-performance liquid chromatography and detected spectrofluorometrically. The method is a significant advance over previous methods because it uses the ion-pairing agent hexadecyltrimethylammonium bromide (HTMA) to facilitate DAPA measurement. Ion-pairing with HTMA avoids interference with co-eluting derivatives to provide simultaneous, sensitive, reproducible measurement of both DAPA peaks (DD,LL-DAPA and DL-DAPA).     

New strategy for quantifying biological zinc by a modified zinpyr fluorescence sensor

Substitution of one pyridine by pyrazine in each DPA appendage of ZP1 leads to a new zinc sensor, ZPP1, with a modified background fluorescence and zinc affinity. ZPP1 exhibits a two-step zinc response during fluorescence titrations, which leads to a new method for zinc quantification. The ability of ZPP1 to image and quantify zinc was demonstrated in pancreatic Min6 cells.     

Asymmetric total synthesis of nigerone

[reaction: see text] An enantioselective synthesis of the chiral bisnaphthopyrone natural product nigerone is reported. The key step was an eight-step isomerization process to form the final natural product. The isomerization precursor was constructed via asymmetric oxidative biaryl coupling of an advanced intermediate with a 1,5-diaza-cis-decalin copper catalyst.