Search results for "Chloride"
showing 10 items of 1691 documents
ChemInform Abstract: A New and Effective Method to Carbazoquinocin C and Related Carbazole-3,4-quinones as Biological Antioxidants: Key Reactions of …
2001
Mechanism of redox transformation of titanocene dichloride centers immobilized inside a polypyrrole matrix—EQCM and XPS evidences
2005
Abstract We report electrochemical quartz crystal microbalance (EQCM) results for electrodeposition of titanocene derivatized polypyrrole p(Tc3Py) films and redox transformation of polypyrrole matrix and titanocene centers immobilized in the film. Films of p(Tc3Py), Tc3Py = Tc(CH 2 ) 3 NC 4 H 4 (Tc = Cl 2 TiCpCp′, Cp = C 5 H 5 , Cp′ = C 5 H 4 ) were obtained from acetonitrile solutions of monomer on a Pt disc or thin Au layer evaporated on 10 MHz quartz crystals. Polymerization efficiency, derived from the slope of the change of resonant frequency as a function of the deposition charge ranged from 54% to 75%. A gradual loss of redox activity of Tc centers during consecutive redox cycles of …
Polymorphism of R-Encenicline Hydrochloride: Access to the Highest Number of Structurally Characterized Polymorphs Using Desolvation of Various Solva…
2019
In a study of the solid form landscape of R-encenicline hydrochloride (Enc-HCl), it was found that this compound is dodecamorphic and presents the first published example of polymorphism with a rec...
Extraction behavior of rutherfordium into tributylphosphate from hydrochloric acid
2007
The extraction behavior of rutherfordium (Rf) into tributylphosphate (TBP) from hydrochloric acid (HCl) has been studied together with those of the lighter group-4 elements Zr and Hf. The extractability of261Rf,169Hf, and85Zr into TBP was investigated under identical conditions in 7.2–8.0 M HCl by on-line reversed-phase extraction chromatography. The percent extractions of Rf, Hf, and Zr into the TBP resin increase steeply with increasing HCl concentration, and the order of extraction is Zr > Hf ≈ Rf. By considering the order of chloride complexation among these elements, it is suggested that the stability of the TBP complex of Rf tetrachloride is lower than those of Zr and Hf.
Unexpected Conformational Behaviour of a Diphosphate Derived from a Spherand-Type Calixarene
2005
The spherand-type calixarene 2a, which consists of three diphenol units linked by methylene bridges, was treated with phosphorus pentachloride and then with water. A C1-symmetrical conformation was found for the resulting bisphosphate 7 in the crystalline state by X-ray analysis, with an anti orientation of the phosphoryl groups. MM3 calculations lead to a nearly identical conformation for the most stable isomer (RRS-twist), while a slightly higher energy was found for an RRS-crown isomer with a syn orientation of the phosporyl groups. Surprisingly, all NMR studies (1H, 13C and 31P) of 7 are in agreement with a dynamic C2 symmetry in solution. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Wein…
1965
Bei der Polymerisation von Trioxan bei 70°C in der Schmelze mit HClO4 · H2O als Initiator nimmt die Bruttopolymerisationsgeschwindigkeit exponentiell mit steigender Wasserkonzentration ab; gleichzeitig nimmt die Lange der Induktionszeit entsprechend zu. Die Retardierung durch Wasser wird auf eine Hydratation aktiver Zentren zuruckgefuhrt. Wasser ist ein wirkungsvoller Polymerisationsubertrager; seine relative Ubertragungskonstante betragt bei 25°C in Methylenchlorid ca. 2,6. Jedoch werden die Verhaltnisse durch die Bildung von Methylenglykol aus Wasser und Formaldehyd kompliziert. In polymerization of trioxane in the melt at 70°C. with HClO4 · H2O as initiator the rate of polymerization dec…
Alkylation of RNA by Vinyl Chloride and Vinyl Bromide Metabolites in Vivo: Effect on Protein Biosynthesis
1981
Alkylation of DNA is viewed as representing the initial critical step in carcinogenesis induced by chemical substances. Vinyl chloride and vinyl bromide, compounds with proven carcinogenic potency toward the liver, are biotransformed to reactive metabolites which covalently bind to DNA (see Bolt et al. 1980). Furthermore, extensive covalent binding of metabolites of both vinyl chloride (Laib and Bolt 1977, 1978) and vinyl bromide (Ottenwalder et al. 1979) occurs to RNA of liver when rats are exposed to both vinyl halides. Defined products of alkylation are 1,N6-ethenoadenosine (Laib and Bolt 1777; Ottenwalder et al. 1979) and 3,N4-ethenocytidine (Laib and Bolt 1978; Ottenwalder et al. 1979)…
Metabolic Activation and Pharmacokinetics in Hazard Assessment of Halogenated Ethylenes
1981
Halogenated ethylenes play an important role in occupational and environmental medicine. Several attempts at toxicological evaluation of such compounds have been recently published (Maltoni 1977; Lee et al. 1978; Gehring et al. 1979; Kappus and Ottenwalder 1980; Henschler et al. 1980; Bolt 1980). The principal question is that of possible carcinogenicity. It is now clear that vinyl chloride (Maltoni 1977) and vinyl bromide (Bolt et al. 1979) are carcinogenic; some data also argue in favor of carcinogenicity of vinylidene chloride (Lee et al. 1978). Trichloroethylene (Henschler et al. 1980) and perchloroethylene (Bolt and Link 1980), according to present data, appear devoid of cancerogenic p…
ChemInform Abstract: Synthesis of the First Benzodiselenagermoles and One Spirobisdiselenagermole.
2010
Abstract The first examples of compounds R1R2GeSe2C6H4R3 (R1,R2=CH3 C2H5, C3H2, n-C4H9, i-C5H11, Ph, p-CH3Ph. R3=H, CH3, OCH3) were easily obtained (40–80% yield) from electrophilic cleavage of diselenophenylene zirconocenes by dialkyl or diaryl dichlorogermanes. The synthesis of a spirodi-selenagermole was achieved in the same way using germanium tetrachloride. Analytical data, 1H and 77Se NMR. mass spectra are perfectly consistent with the expected structures.
ChemInform Abstract: Boron Aldol Additions with Erythrulose Derivatives: Dependence of Stereoselectivity on the Type of Protecting Group.
2010
Abstract Boron aldol additions of 1- O -silylated 3,4-di- O -benzyl- and 3,4-di- O -benzoyl- l -erythrulose and achiral aldehydes using dicyclohexylboron chloride have been investigated. The dibenzyl derivative gave syn/syn stereoisomers with high stereoselectivity, whereas the dibenzoyl derivative gave syn/anti stereoisomers. It is believed that, while the dibenzoyl erythrulose gives rise to the E enolate in the presence of dicyclohexylboron chloride, as usually observed with this reagent, only the Z enolate is formed in the case of the dibenzyl derivative.