- Aza- and thiaarsolidinium cations: Novel structural features for carbene analogues
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The preparation, isolation, and structural characterization of salts containing the first arsolidinium cations are reported. Reactions between equimolar amounts of 2-chloro-1,3-dimethyl-1,3-diaza-2-arsolidine or 2-chloro-1,3-dithia-2-arsolidine with AlCl3 or GaCl3 result in quantitative chloride ion abstraction to give the corresponding cations [N(Me)CH2CH2N(Me)As]+ and [SCH2CH2SAs]+ as tetrachloroaluminate and gallate salts. X-ray crystallography reveals a centrosymmetric dimeric arrangement for three derivatives in which the cations are bound together by relatively weak As-N or As-S interactions. A complex between the respective chloroarsolidine and arsolidinium cation is formed in reaction mixtures which provide appropriate stoichiometry. The X-ray structure of the thia derivative, [SCH2CH2SAsSAs(Cl)SCH2CH2] [GaCl4], shows a single, noticeably weaker interring connection, but otherwise the compound exhibits similar structural features. The aza derivative of the complex can be readily interconverted with the dicationic diazarsolidinium upon addition of a Lewis acid. Variable temperature 1H NMR spectroscopy shows both the dication dimers and the complexes to be fluxional in solution, and a dissociative process is envisaged. Consequently, the cations are viewed as examples of stable arsenium (carbene analogue) units, unique in the absence of a steric shield or Hückel T-delocalization. The weakly associated structures represent alternatives to alkenic dimerization, typical of carbenes.
- Burford, Neu,Parks, Trenton M.,Royan, Bruce W.,Borecka, Bozena,Cameron, T. Stanley,Richardson, John F.,Gabe, Eric J.,Hynes, Rosemary
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- Synthesis, spectroscopic, structural characterization, and antimicrobial studies of 1,3-dithia-2-arsacyclopentane derivatives with oxygen and sulfur donor ligands
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Some mixed 1,3-dithia-2-arsacyclopentane derivatives with oxygen and sulfur donor ligands have been synthesized by the reaction of 2-chloro-1,3-dithia-2- arsacyclopentane and oxygen and sulfur donor ligands (benzoic acid, thiobenzoic acid, sodium acetate, thioacetic acid, phenol, thiophenol, sodium salicylate, and thioglycolic acid) in equimolar ratio (1:1) in refluxing anhydrous benzene solution. These white or yellow solids/liquids derivatives have been characterized by melting points, molecular weights, elemental analyses (C, H, S, and As), and spectroscopic [UV, IR as well as NMR (1H and 13C)] studies. Tentative structures are proposed on the basis of the spectroscopic results. The free ligands and the corresponding arsenic compounds exhibited good activities as antibacterial and antifungal agents on some selected bacterial and fungal strains. Chloroamphenicol and terbinafin were used as standards for comparison. 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. Copyright Taylor & Francis Group, LLC.
- Chauhan,Bhatiya, Sumit,Bakshi, Abhilasha,Makwana
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experimental part
p. 511 - 519
(2011/05/15)
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- Structural characteristics of 2-halo-1,3,2-dithiarsenic compounds and tris-(pentafluorophenylthio)-arsen
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The combination of various dithiols and AsX3 (X = F, Cl) produces the series of cyclized halo-arsenic dithiolate compounds: 2-chloro-1,3,2-dithiarsolane [AsCl(SCH2CH2S)] (1), 2-iodo-1,3,2-dithiarsolane [AsI(SCH2CH2S)] (2), 2-chloro-1,3,2-dithiarsenane [AsCl(SCH2CH2CH 2S)] (3), 2-iodo-1,3,2-dithiarsenane [AsI(SCH2CH 2CH2S)] (4), 3-chloro-4H,7H-5,6-benz-1,3,2-dithiarsepine [AsCl(SCH2)2(C6H4)] (5), 1,2-bis-dithiarsolan-2-ylmercapto-ethane [As2(SCH2CH 2S)2(SCH2CH2S)] (6) and tris-(pentafluorophenylthio)-arsen [As(SC6F5)3] (7). The geometry around As for these compounds is best described as trigonal pyramidal with varying degrees of distortion. Compound 1 crystallizes in two polymorphic forms with similar structural parameters. The compounds have been characterized by IR, 1H, 19F, and 13C NMR, X-ray crystallography and GC-MS.
- Shaikh, Taimur A.,Bakus II, Ronald C.,Parkin, Sean,Atwood, David A.
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p. 1825 - 1833
(2007/10/03)
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