- ORGANOZINN- UND ORGANOBLEIDERIVATE VON N-(2,4-DINITROPHENYL)GLYCIN
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Organotin and organolead derivatives of N-(2,4-dinitrophenyl)glycine (HDNG), R3MDNG (M = Sn, Pb; R = CH3, C6H5) and (C6H5)2Pb(DNG)2, have been prepared from R3MOH or n and HDNG, respectively. (CH3)3PbDNG was also obtained from (CH3)3PbBr and TlDNG.According to spectroscopic data R3M groups in R3MDNG are essentially planar and are bridged by bidentate carboxylate groups of DNG.NH does not coordinate to M.Pentacoordination is also indicated by Moessbauer data of R3SnDNG.Also for (C6H5)2Pb(DNG)2 a chain structure but with hexacoordination of Pb is proposed.The compounds are monomeric in solution.
- Huber, F.,Roge, G.,Barbieri, R.,Bianca, F. Di
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- A utility for organoleads: Selective alkyl and aryl group transfer to tin
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Me4Pb and Ph4Pb readily transfer methyl or phenyl groups to an equivalent molar ratio of tin(iv) chlorides in the order SnCl4 > MeSnCl3 > Me2SnCl2 > Me3SnCl, often in a selective manner. Me3PbCl and Ph3PbCl specifically transfer a single methyl/phenyl group under the same reaction conditions to produce recovered yields in >75%. Specific transfer of 2 methyl groups from PbMe4 can be achieved at elevated temperatures and/or a 2:1 molar ratio Pb:Sn.
- Arias-Ugarte, Renzo N.,Pannell, Keith H.
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p. 1703 - 1708
(2018/02/09)
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- Chemistry of C6F5SeLi and C6F 5SeCl: Precursors to new pentafluorophenylselenium(II) compounds
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Pentafluorobenzeneselenenyl chloride, C6F5SeCl, was reacted with various nitrogen and chalcogen substituted trimethylsilyl nucleophiles. The products, C6F5SeSCN, C6F 5SeNSO, (C6F5Se)2NMe, C 6F5SeN(Me)SiMe3, (C6F 5Se)2S and (C6F5Se)2Se, were characterized by spectroscopic methods. The reaction of C6F 5SeLi with Me3XHal compounds gave the products C 6F5SeXMe3 (X = Si, Ge, Sn, Pb). The molecular structure of (C6F5Se)2S has been determined by X-ray diffraction.
- Klap?tke, Thomas M.,Krumm, Burkhard,Mayer, Peter
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p. 547 - 553
(2007/10/03)
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- Synthesis and spectroscopic characterization of new organolead(IV) complexes containing organophosphorus ligands
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Organolead(IV) derivatives of organophosphorus ligands, RnPb[(OPPh2)(SPPh2)N]4-n (R = Ph; n = 2, 3) and Me3Pb[S2PR2] (X = S, O; R = Me, Et, Ph), were prepared by reacting the corresponding organolead(IV) chloride with the sodium, potassium or ammonium salt of the appropriate organophosphoric acid. The title compounds were investigated by IR and multinuclear (1H, 13C, 31P) NMR spectroscopy, and possible structures are proposed. All dithiophosphinato complexes exhibited low stability and underwent decomposition on standing. The decomposition process was monitored by using 1H and 31P NMR spectroscopy, and a decomposition pathway is proposed.
- Varga, Richard A.,Silvestru, Cristian,Haiduc, Ionel
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p. 485 - 498
(2008/10/08)
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- Organolead derivatives of coordinatively saturated platinum(II) olefin complexes. Molecular structure of [PtCl(PbPh2Cl)(2,9-dimethyl-1,10-phenanthroline)(dimethyl maleate)] and its deplumbation product [PtCl(Ph)(2,9-dimethyl-1,10-phenanthroline)(dimethyl maleate)]
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The stabilization of Pt(II)-PbR2Cl linkages (R = Me, Ph) is reported. The compounds of general formula [PtCl(PbR2Cl)(N-N)(olefin)] (N-N = 2,9-dimethyl-1,10-phenanthroline (dmphen) and 6-methylpyridine-2-phenylimine (pimpy)) have been obtained through the oxidative addition of PbMe2Cl2 and PbPh2Cl2 to three-coordinate Pt(O) complexes [Pt(N-N)(olefin)]. In the presence of less hindered N-N ligands (e.g., 2-methyl-1,10-phenanthroline) the addition leads only to the isolation of the mononuclear Pt(II) complexes [PtCl(R)(N-N)]. The molecular structure of [PtCl(PbPh2Cl)(dmphen)(dimethyl maleate)] has shown that the Pt-Pb bond is stabilized by an additional interaction of a carboxylate oxygen to the lead atom. The deplumbation product [PtCl(Ph)(dmphen)(dimethyl maleate)] has also been characterized by X-ray crystallography.
- Albano, Vincenzo G.,Castellari, Carlo,Monari, Magda,De Felice, Vincenzo,Ferrara, Maria L.,Ruffo, Francesco
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p. 4213 - 4221
(2008/10/09)
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- Trimethyllead-Lithium in Tetrahydrofuran: Synthesis of Trimethyl(trimethylplumbyl)silane and of the Trimethylplumbyltrihydridoborate Anion
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Solutions of trimethyllead-lithium Li (1), in tetrahydrofuran (THF) (ca. 0.5 M) can be obtained from trimethyllead bromide and an excess of lithium at -78 deg C. 1H, 13C and 207Pb NMR are used for monitoring the formation of the reagent.Extensive decomposition into lead and tetramethyllead is observed at -20 deg C within minutes.The application of this reagent is demonstrated by the synthesis of trimethyl(trimethylplumbyl)silane (2) and its stoichiometric 1:1 reaction with BH3-THF at -78 deg C, leading to lithium trimethylplumbyltrihydridoborate Li (3).The composition of the products in solution follows conclusively from their 1H, 11B, 13C, 29Si, and 207Pb NMR data.The silane 2 decomposes slowly at ambient temperature into Me4Si, Me4Pb and lead.The borate is even less stable, decomposing at temperatures above -30 deg C mainly into lead, Me4Pb, Li and Li. - Keywords: Trimethyllead-Lithium, Trimethyl(trimethylplumbyl)silane, Trimethylplumbyltrihydridoborate Anion, NMR Spectra
- Wrackmeyer, Bernd,Horchler, Klaus
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p. 1195 - 1198
(2007/10/02)
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- REACTIONS OF BIS(η-CYCLOPENTADIENYL)DIHYDRIDO-MOLIBDENUM AND TUNGSTEN WITH ACETATOTRIMETHYL-LEAD. X-RAY STRUCTURE AND REACTIVITY OF THE DEMETHYLATED LEAD PRODUCT CONTAINING MOLYBDENUM-LEAD BONDS:μ-DIACETATOPLUMBIO-BIS (2 Pb-Mo)
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Novel transition metal-lead bonded complexes of the bis(η-cyclopentadienyl) class of organometallic compounds hawe been formed by the demethylation of acetatotrimethyl-lead in the presence of the molybdenum and tungsten dihydrides.An X-ray structure analysis of the molybdenum derivative has established the presence of a Mo-Pb-Mo linkage and a hydride ligand.The complex reacts with cyanoacetylene (HCCCN) giving a bis(alkenyl) compound .
- Kubicki, Marek M.,Kergoat, Rene,Guerchais, Jacques-E.,L'Haridon, Paul
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p. 1791 - 1794
(2007/10/02)
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- Tris(trimethylsilyl)methyl-lead Oxinates: Their Solvolysis, Redistribution, and Reductive Elimination Reactions
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The complex PbMe2(ox) (where ox = the anion of 8-hydroxyquinoline) is stable to boiling ethanol over short periods, but on prolonged heating undergoes redistribution and reductive elimination reactions yielding Pb(ox)2, PbMe3(ox), PbMe3, and 8-methoxyquinoline.By contrast, when PbCl2Me is treated with 8-hydroxyquinoline at pH ca. 10 in methanol, ethanol, or aqueous dioxan the bis(trimethylsilyl)methyl complex PbMe(ox)2 (1) is formed together with SiMe3(OR) (R = H, Me, or Et) rather than the expected tris(trimethylsilyl)methyl complex.Refluxing (1) in ethanol or aqueous dioxan results in further nucleophilic displacement of SiMe3 groups yielding , successively, PbMe(CH2SiMe3)(ox)2 (2) and PbMe2(ox)2 (3).These cleavage reactions occur in competition with disproportionation and reductive elimination processes, the final products derived from (3) being Pb(ox)2, PbMe4, PbMe3(ox), and 8-methoxyquinoline.The corresponding 8-hydroxy-2-methylquinolinate complexes are also examined.
- Glockling, Frank,Gowda, N. M. Nanje
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p. 2191 - 2196
(2007/10/02)
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- A kinetic study of the redistribution reaction of Me4-nPb[M(CO)5]n (M = Mn, Re; n = 1, 2; Me = CH3)
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In the system Me4Pb/Me3Pb[M(CO)5]/Me2Pb[M( CO)5]2 (Me = CH3; M = Mn, Re) redistribution can occur. The single reactions involved, disproportionation of Me3Pb[M(CO)5] (M = Mn, Re) and conproportionation of Me4Pb and Me2Pb[Mn(CO)5]2 to Me3Pb[Mn(CO)5]2 have been investigated kinetically by 1H NMR spectroscopy in various solvents, and initial phase rate constants have been determined. Both types of reactions proceed according to a 2nd order rate law. Conproportionation is faster than Re compounds. The solvent dependency of the reaction can be explained when a reaction mechanism via a bridged transition state is assumed.
- Koedel,Huber,Haupt
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p. 209 - 212
(2008/10/08)
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- ORGANOMETALLOIDAL DERIVATIVES OF THE TRANSITION METALS VII. THE THERMAL AND PHOTOCHEMICAL PROPERTIES OF TRIALKYLLEAD DERIVATIVES OF Cr, Mo AND W
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Trimethyl-and triethyllead derivatives (η5-C5H5)M(CO)3PbR3 (M = Cr, Mo, and W) have been synthesized.The trimethyllead derivatives are photochemically, and to a lesser extent, thermally unstable with respect to methyl transfer reactions that yield the corresponding (η5-C5H5)M(CO)3CH3 complex.The related triethyllead complexes behave in a distinctly different fashion exhibiting rearrangements to 5-C5H5)M(CO)3>3PbEt2 (M = W, Mo).The reactions of the Cr, Mo, and W complexes with SO2 yielded the corresponding alkyl sulphinato complexes as did the reaction of t he related Fe complex 5-C5H5)Fe(CO)2PbEt3>.
- Pannell, K. H.,Kapoor, R. N.
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- ORGANOLEAD CHEMISTRY. VII. REMOVAL OF ETHYLLEAD COMPOUNDS FROM AQUEOUS SOLUTION BY REACTION WITH ZINC
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Triethyllead chloride in aqueous solution reacts with zinc to give hexaethyllead as the major product.The reaction proceeds in two steps with the removal of soluble organolead species from solution being faster than the formation of hexaethyllead.Diethyllead dichloride also gives hexaethyllead on reaction with zinc, and triethyllead(IV) species were detected at intermediate stages of reaction.It is argued that hexaethyllead is not formed by reactions involving compounds with lead-zinc bonds but probably by dimerisation of Et3Pb. radicals.The reactions have application in the treatment of effluents from the manufacture of tetraethyllead.
- Hitchen, Martin H.,Holliday, A. Kenneth,Puddephatt, Richard J.
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p. 335 - 342
(2007/10/02)
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