Bis(2-mercaptobenzoxazolato)mercury(II) and bis(2-pyridinethiolato)mercury(II) complexes as carriers for thiocyanate selective electrodes

Highly selective poly(vinyl chloride) (PVC) membrane electrodes based on bis(2-mercaptobenzoxazolato)mercury(II) [Hg(MBO)₂] and bis(2-pyridinethiolato)mercury(II) [Hg(PT)₂] complexes as new carriers for thiocyanate-selective electrodes are reported. The electrodes were prepared by coating the membrane solution containing PVC, plasticizer, carriers and additives on the surface of graphite electrodes. Influence of the membrane composition, pH and possible interfering anions were investigated on the response properties of the electrodes. Both sensors exhibited Nernstian responses towards thiocyanate over a wide concentration range of 1×10⁻⁶ to 0.1 M, with slopes of 60.6±0.8 and 57.5±1.2 mV per decade of thiocyanate concentration for Hg(MBO)₂ and Hg(PT)₂ carriers, respectively, over a wide pH range of 3-11. The limit of detection for both electrodes was ∼6×10⁻⁷ M. The sensors have response times of ≤5 s and can be used for at least 2 months without any considerable divergence in their potential response. The proposed electrodes show fairly good discrimination of thiocyanate over several inorganic and organic anions. The electrodes were successfully applied to direct determination of thiocyanate in saliva and as indicator electrodes in precipitation titrations.     

Zinc(II) and Cadmium(II) Metal Complexes with Bis(tetrazole) Ligands: Synthesis and Crystal Structures

Two new metal complexes [Zn( L¹ )]_n ( 1 ) and [Cd₃( L² )₂Cl₂(H2O)6]_n ( 2 ) (H₂ L¹ = 1,5‐bis(tetrazol‐5‐yl)‐3‐oxapentane, H₂ L² = bis(tetrazol‐5‐yl)methane) have been synthesized and characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction analysis. Complex 1 was a 2‐D sheet constructed by L¹ and Zn(II) center, further assembled to form a three‐dimensional (3‐D) supramolecular networks through weak hydrogen‐bonding interactions. In the complex 2 , there were two unequivalent Cd(II) centers, and some of ligands L² adopted chelate coordination mode, and others adopted bridge coordination mode linking the Cd1 center and simultaneously bridging the Cd2 center, the Cl^‐ anions adopted μ₂ bridging mode, ligands L² and the Cl^‐ anions linked the Cd(II) centers to form a 3‐D supramolecular networks.     

Synthesis of Bis{1,2,4-tri(tert-butyl)cyclopentadienyl}mercury by Transfer of Alkylated Cyclopentadienyl Rings from Bismuth to Mercury (Transmetallation)

Bis{1,2,4-tri(tert-butyl)cyclopentadienyl}mercury 2 has been obtained by sodium amalgam reduction of Chlorobis{1,2,4-tri(tert-butyl)cyclopentadienyl}bismuth. The crystal structure of 2 (P1 , a = 10.564(4) Å, b = 11.8230(10) Å, c = 15.546(4) Å, α = 69.160(10)°, β = 82.49(2)°, γ = 64.100(10)°, V = 1 631.7(8) ų) consists of a linear two-coordinated mercury complex with σ bonded tri(tert-butyl)cyclopentadienyl rings. In solution 2 is fluxional on the NMR time scale even at 165 K.     

Preparation of samarimm(ii) sulfide by the reaction of samarium(II) bis[bis(trimethylsilyl)amide] with hydrogen sulfide

X-ray amorphous samarium(II) sulfide was prepared by the reaction of H₂S with samarium(II) bis[bis(trimethylsilyl)amide] (1) in THF at 10^–2 Torr. Compound1 was prepared by two methods: 1) the reaction of SmI₂ with lithium bis(trimethylsilyl)amide and 2) the reaction of samarium naphthalide with bis(trimethylsilyl)amine. SmS was transformed to the polycrystalline state with the lattice parametera = 5.92 Å by annealing at 400–500 °C.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 241–243, February, 1995.     

Samarium(II) Iodide Promoted Tandem Reductive Fragmentation and Aldol Reaction

Summary.  We report a new reductive fragmentation/aldol tandem reaction in a 1,4-diketone induced by samarium(II) iodide. Due to the particular stereoelectronic situation in the molecule, an alternative pathway was avoided despite the fact that it would have greatly reduced the strain in the tricyclic molecule. Received February 23, 2001. Accepted March 7, 2001     

Solvent Effect on the Ligand Exchange between Bis(diethyldithiocarbamato)copper(II) and Bis(diethyldiselenocarbamato)copper(II)

EPR and spectrophotometric study on the products of ligand‐exchange taking place on mixing bis(diethyldiselenocarbamato)copper(II), [Cu(Et₂dsc)₂], and bis(diethyldithiocarbamato)copper(II), [Cu(Et₂dtc)₂], solutions is reported. EPR spectra monitored at room temperature for one month period reveal a stable equilibrium among the parents (chromophores CuS₄ and CuSe₄) and the obtained mixed‐chelate [Cu(Et₂dtc)(Et₂dsc)] complex (chromophore CuS₂Se₂) in heptane, hexane, benzene, toluene, acetone, DMFA, DMSO and dichloromethane. In CCl₄ and CHCl₃ two new additional EPR spectra appear attributed to the mixed‐chelate complexes with the chromophores CuSSe₃ and CuS₃Se which are not observed with electronic spectroscopy. The intensities of all five EPR spectra decrease with the time. It is assumed that the new mixed‐chelates observed in CCl₄ and CHCl₃ are obtained in a reaction of [Cu(Et₂dtc)(Et₂dsc)] or [Cu(Et₂dtc)₂] with the ester of diselenocarbamic acid which is formed in a parallel reaction of [Cu(dsc)₂]with CCl₄ or CHCl₃.     

Samarium(II)-induced coupling of acid chlorides with allylic halides

Samarium(II)-induced coupling of acid chlorides with allylic halides gave diallylated tertiary alcohols. Monoallylated allylic ketones could not be obtained.     

双桥连二环戊二烯基金属有机化合物的研究进展

综述了双桥连二戊二烯基金属有机化合物的研究进展，根据桥链以及金属原子 的不同，分别讨论了它们的合成、结构及在催化烯烃聚合上的应用。     

二环戊二烯基二羰基钛的化学

本文对二环戊二烯基二羰基钛(1),的化学作了较详细的评述。第一部分叙述了合成1的多种不同方法及其结构和性质。第二部分详述了1的各种反应,包括铁金属价态变化的反应和钛价不变的反应。同时也涉及近年来1和其他类型金属有机化合物生成多核金属有机化合物或簇合物的反应。最后还讨论了1对无机小分子的活化反应。     

Crystallographic report: Bis(µ2‐chloro)‐{bis(diethylether)‐lithium}‐bis(η5‐pentamethyl‐cyclopentadienyl)samarium(III)

The structure is mononuclear with samarium bound by two η⁵‐cyclopentadienyl ligands and two chloride ligands, the latter of which bridge to a doubly ether‐solvated lithium centre. Copyright © 2004 John Wiley & Sons, Ltd.     

Rhodium(III), palladium(II) and platinum(II) complexes of Bis(o-aminobenzenesulfonyl)ethylenediamine

New complexes of the formulae K₃[RhL ₃]·2 H₂O, [PdL]·H₂O and [M(LH₂)Cl₂] [whereM = Pd, Pt andLH₂ = bis(o-aminobenzenesulfonyl)ethylenediamine] have been prepared and characterized by conductivity measurements, thermogravimetric analysis, X-ray powder patterns and IR, Ligand Field and¹H-NMR spectroscopy.

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Rhodium(III), Palladium(II)- und Platin(II)-Komplexe mit Bis(o-aminobenzolosulfonyl)ethylendiamin (Kurze Mitteilung)

Zusammenfassung Neue Komplexe der allgemeinen Formeln K₃[RhL ₃]·2H₂O, [PdL]·H₂O und [M(LH₂)Cl₂] mitM = Pd, Pt undLH₂ = Bis(o-aminobenzolosulfonyl)ethylendiamin wurden dargestellt und mit Konduktionsmessungen, thermogravimetrischen Analysen, Röntgenstrukturanalysen, IR, Ligandfeld- und¹H-NMR-Spektroskopie charakterisiert.

     

Samarium(II) dibromide-promoted selective deprotection of a benzoyl protective group

The selective deprotection of a benzoyl group was very important methodology in the field of organic synthesis. Various methods for debenzoylation were investigated and developed in the past six decades, but more useful and selective strategies are now being strongly desired. In response to this strong demand, we developed the novel and selective deprotection of a benzoyl group by use of samarium(II) dibromide and a proton source. This deprotective reaction proceeded smoothly and the desired compound was obtained in good to excellent yields. In this paper, we will report the details of this deprotective reaction.     

Spektroskopische Eigenschaften von Bis(imidazol)kupfer(II)diacetat

Summary Electronic and vibrational spectra of bis(imidazol)copper(II)diacetate were investigated in order to obtain a wider insight into the structural properties of this interesting complex compound, which presents high cytotoxic activity. Electronic transitions were investigated by reflectance measurements of the solid and by absorption, using aqueous and methanolic solutions. IR spectra could be interpreted on the basis of the characteristic ligand vibrations. Some information could also be obtained for the Cu-N and Cu-O vibrations. For comparative purposes, the IR spectrum of Cu(imidazol)₄I₂ was also recorded and analyzed.

     

二碘化钐作用下缺电子烯烃的还原偶联反应

室温下SmI2-HMPA-t-BuOH-THF体系能顺利地将丁烯二酸二酯还原偶联为1, 2, 3, 4-四烷氧基羰基丁烷, 同样条件下, 亚苄基氰乙酸乙酯,α-乙氧羰基肉桂酸乙酯, α-乙酰基肉桂酸乙酯和亚苄基丙二酸亚异丙酯等化合物也发生还原偶联反应得到相应的二聚体。     

Development of novel and efficient synthesis of group 14 element (Ge and Sn) catenates by use of samarium (II) diiodide

Group 14 element catenates such as di-, tri-, poly-germanes, and polystannanes are efficiently synthesized by use of the one-electron reducing agent SmI₂ under mild homogeneous conditions in good yields.     

EMR Study of Bis(benzene-dithiocarboxylato)copper(II) Complex in Solution and Magnetically Diluted in Different Host Lattices

EMR studies of bis(benzene-dithiocarboxylato)copper(II) in the form of the pure solid sample, in solution as well as magnetically diluted in the host lattices of the corresponding complexes of Ni^II, Zn^II, Pd^II, and Pt^II are reported. Two different samples (violet and blue) have been obtained in the Ni^II complex host lattice with EMR spectra indicating a superposition of several individual Cu^II signals. The EMR spectrum of the violet sample is explained by a superposition of the individual signals of (thio-, perthio-carboxylate)Cu^II and bis(perthiocarboxylate)Cu^II while that for the blue Cu/Ni(dtb)₂ complex, as well as for Cu/Pd (dtb)₂ is explained by different positions of the Cu^II species in the host lattices. The EMR spectrum typical for the magnetically diluted sample caused by self redox reaction has been recorded in the pure solid sample of copper(II) dithiocarboxylate complex.     

Effects of Samarium on the Properties of the Anodic Pb（Ⅱ） Oxides Film Formed on Pb in Sulfuric Acid Solution

The effects of samarium on the properties of the anodic Pb(II) oxides films formed on lead at 0.9 V (vs. Hg/Hg₂SO₄) in 4.5 mol/L H₂SO₄ solution were studied using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and scanning electron micrographs (SEM). The experimental results show that adding Sm to lead metal can inhibit the growth of the Pb(II) oxides film effectively, and reduce the resistance of the PbO oxides film obviously. The addition of Sm increases the porosity of the anodic film, which may cause the increase of the ionic conductance produced by the interstitial liquid among the PbO particles in the film and lead to the decrease of the resistance of the anodic film.     

Effects of Samarium on the Properties of the Anodic Pb(II) Oxides Film Formed on Pb in Sulfuric Acid Solution

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Preparation and Spectral Investigation of Bis[N(2-methyl-phenyl) 4-Nitro-thiobenzamidato] mercury(II), Bis[N(2-methoxy-phenyl) 4-Nitro-thiobenzamidato]mercury(II), and Bis[N(2-chloro-phenyl) 4-Nitro-thiobenzamidato]mercury(II) Complexes

Several preparative routes to bis[N(substituted-phenyl) 4-nitro-thiobenzamidato] mercury(II) complexes are presented, including the reaction of mercury(II) oxide, fluoride, chloride, bromide, cyanide, acetate, and nitrate with N(substituted-phenyl) 4-nitro-thiobenzamide derivatives. ¹ H-NMR, Raman, and IR measurements confirmed the complexation of mercury to sulphur.