- 3-(2-Furyl)-2-sulfanylpropenoic acid as a chelating agent for lead(II) and diorganonolead(IV) compounds - Chemical behaviour and in vitro protective effect against dimethyllead(IV) toxicity
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The reaction of the title acid (H2fspa) with lead(II) acetate and dimethyl- or diphenyllead(IV) acetate in alcoholic medium gives the 1:1 complexes [Pb(fspa)] and [PbR2(fspa)] (R = Me, Ph). When the reaction was carried out in the presence of diisopropylamine (Q), the [HQ] 2[Pb(fspa)2] and [HQ]2[PbPh2(fspa) 2] derivatives formed in low yield. Additionally, the compounds Na[PbMe2(OAc)3], [PbPh2(fspa)(DMSO)] and [PbPh2(fspa)(DMSO)]·DMSO were also isolated as crystalline solids in subsequent crystallization processes. All these compounds were characterized by IR and NMR (1H and 13C) spectroscopy and, in some cases, by X-ray diffractometry and 207Pb NMR spectroscopy. Pig renal proximal tubule LLC-PK1 culture cells were used to determine in vitro the nephroprotective effect of H2fspa, [HQ]2[Zn(fspa) 2], vitamin B1 and vitamin B6 against PbMe 2(NO3)2 toxicity. The beneficial effects of the acid, the zinc(II) complex and/or their combinations with vitamin B1 (thiamine nitrate) are described. Copyright
- Casas, Jose S.,Castano, M. Victoria,Couce, Maria D.,Sanchez, Agustin,Sordo, Jose,Torres,Vazquez Lopez, Ezequiel M.
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- Silicon-lead chalcogenides of the types Me4Si2(E)2PbPh2 and Ph2Pb(E)2Si2Me2 (E)2PbPh2 (E = S, Se) and related compounds containing tin and antimony
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The reaction of a 1:1 mixture of Ph2PbCl 2 and ClSiMe2-SiMe2Cl with H2S/NEt3 yielded the mixed silicon-lead sulfide Me4Si2(S)2PbPh2 (1a), a bicyclic silicon lead sulfide, Ph2Pb(S) 2Si2Me2(S)2PbPh2 (1b) was obtained by similar treatment of a 2:1 mixture of Ph2 PbCl2 and Cl2SiMe-SiMeCl2. The corresponding selenium compounds (2a-b) were obtained by reactions of mixtures of Ph2PbCl2 and methylchlorodisilanes with Li2Se in THF. All products were characterized by multinuclear (1H, 13C, 29Si, 77Se and 207Pb) NMR spectroscopy. The molecular structure of 1a is reported revealing a central five membered ring Si2S2Pb in envelope conformation with one sulfur atom (S1) above the plane defined by the atoms Pb1-S2-Si2-Si1. For comparison, the tin compounds Me4Si2(Se) 2SnPh2 (4a), and Ph2Sn(Se) 2Si2Me2(Se)2SnPh2 (4b) have also been prepared essentially applying the same procedure as for compounds 2a-b. A plot of δ (207Pb) of 1a-2b versus δ (119Sn) of the corresponding tin compounds 3a-4b exhibits a linear correlation with a slope of 4.11 (±0.17). Attempts to build related cycles containing a Group 15 element led to the isolation of the antimony compounds Me4Si2 (E)2SbPh (5a: E = S, 5b: E = Se) starting from ClSiMe2-SiMe2-SiMe2Cl, PhSbCl2 and either H2S/NEt3 or Li2Se.
- Herzog, Uwe,Rheinwald, Gerd
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p. 220 - 225
(2007/10/03)
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- Synthesis and some reactions of tris (pentafluorophenyl) antimony compounds
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(C6F5)3Sb has been found to react with interhalogens and halo-pseudohalogens, IX(X = Cl, Br, N3 and NCO), pseudohalogen (SCN), and elemental sulphur to give oxidative addition products (I-VI). (C6F5)3SbS(VI) may also be prepared by the reaction of (C6F5)3SbCl2 with H2S. Metathetical reactions of (C6F5)3SbCl2 with appropriate metallic salts yield covalent pentacoordinate disubstituted products (V, VII-XII) of the general formula, (C6F5)3SbY2 (Y = NCS, NCO, -ONCMe2, -ONCMePh -NCO(CH2)2CO and p-NO2C6H4OCO). Treatment of (C6F5)3SbCl2 with aqueous NaN3 gives the binuclear oxo-bridge compound, [(C6F5)3SbOSb(C6F5)3](N3)2·(III) and (IV) are also accessible by displacement reaction of (I) or (II) with the corresponding metallic salt. Molecular weight, conductance measurements, and IR spectra on the new organoantimony(V) derivatives have been obtained. Reductive cleavage reactions of (C6F5)3SbS with hexaaryldileads, Ar6Pb2(Ar = Phenyl, p-tolyl) produce (C6F5)3Sb and the corresponding bis(triaryllead) sulphide but treatment of (C6F5)3SbX2(X = NCO, Cl) with Ar6Pb2 gave Ar4Pb and Ar2PbX2 together with (C6F5)3Sb. (C6F5)3SbCl2 and bis(triorganotin)sulphides undergo exchange of anionic groups.
- Raj, Prem,Saxena,Singhal, Kiran,Ranjan, Ashok
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p. 251 - 258
(2008/10/08)
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- The Chemistry of (Cyclopentadienyl)phenyl-lead(IV) Compounds
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The yellow air-stable (cyclopentadienyl)phenyl-lead(IV) compounds, PbPh(4-n)(cp)n , have been synthesised by the reaction of the corresponding phenyl-lead(IV) chloride and lithium cyclopentadienide in diethyl ether.Crystals of PbPh3(cp) are monoclinic, space group P21/c, with a = 9.5426, b = 12.3843, c = 16.1714 Angstroem, β = 102.3358 degree, and Z = 4, and comprise discrete non-interacting molecules with a distorted tetrahedral geometry.The Pb-C(cp) bond distance is significantly longer than the Pb-C(Ph) distances , indicating a substantial weakening of this bond.The endocyclic C-C bonds of the cyclopentadienyl ring (which is planar) are consistent with a concentration of ?-electron density over the carbon atoms remote from the lead.Reaction of PbPh3(cp) with acetic acid, thiophenol, and imidazole proceeds with exclusive Pb-C(cp) bond cleavage affording PbPh3(O2CMe), PbPh3(SPh), and PbPh3(N2C3H3), respectively.Only PbPh4 was isolated from the reaction with 4-chlorophenol.The compound PbPh2(cp)2 decomposes on attempted sublimation at 60-70 deg C and 0.01 mmHg giving Pb(cp)2, whilst reaction with hidrogen chloride, carboxylic acids, and imidazole yields the corresponding diphenyl-lead(IV) derivative.Cleavage of all four Pb-C bonds occurs on reaction with thiols, when lead(II) thiolates are the products.Reaction with phenols yields products of composition n which presumably contain metal-metal bonds.The mechanisms of the reactions are discussed.
- Gaffney, Christine,Harrison, Philip G.
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p. 1055 - 1060
(2007/10/02)
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