- Reactivity and properties of [-O-BiIII...O=Mo-]n chains
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A coordination polymer [Cp*(O)2Mo-O-Bi(o-tolyl) 2]n, II, containing Mo-O-Bi and Mo=O...Bi moieties was investigated with respect to its behavior in contact with OH- and Cp2MoH2 and as potential single source precursor in the polyol method. It turned out that hydroxide as a base breaks up the polymer to yield Cp*MoO3- and (o-tolyl)2BiOH. The latter polymerizes to give the coordination polymer [(o-tolyl) 2BiOH]n, 1. Alternatively, 1 can be prepared by reacting [(o-tolyl)2Bi(hmpa)2]SO3CF3 with NBu4OH/H20 in thf/water. If, however, NBu 4OH/MeOH is used in dichloromethane as the solvent, the (o-tolyl)2BiOH formed intermediately undergoes methanolysis, and finally, [(o-tolyl)2BiOMe]n, 3, is isolated. Although 1 and 3 are very similar compounds, their crystal structures differ significantly: while the structure of 1 is dominated by secondary bonding leading to seesaw-type coordination geometries around the Bi centers, the Bi atoms in 3 are coordinated in a distorted tetrahedral fashion, and secondary bonding plays only a minor role. If 1 is dissolved in a nonpolar, nonprotic solvent, condensation reactions occur immediately leading to [(otolyl) 2BiOBi(o-tolyl)2], 2, which can be obtained on a preparative scale this way. Compound 3 which can be prepared in good yields may prove to be a useful starting material in bismuth chemistry. Here, it was shown to react with molybdocene dihydrides to provide stable Bi-substituted molybdocene monohydrides [RCp2-Mo(H)(Bi(o-tolyl) 2)] (R = Me 4, R = H 5); compounds of that type were identified in solution before but had so far eluded isolation. Compound 4, whose crystal structure is discussed, also forms when II is treated with methylated molybdocene dihydride. This obviously leads to the formation of Mo-Bi bonds (→ 4), as well as Mo-OH units, which undergo condensation reactions leading to Mo-O-Mo moieties (i.e., [Cp*2Mo2O5] is formed as a byproduct). The use of II as precursor in the polyol method successfully led to bismuthmolybdate nanoparticles (accompanied by crystallites); however, no single phase is obtained, but biphasic materials consisting of Bi2Mo2O9 and Bi 2MoO6, whose ratio can be determined by the choice of the hydrolyzing reagent, are formed instead. One of these materials proved to be capable of sensing EtOH selectively at elevated temperatures.
- Roggan, Stefan,Limberg, Christian,Ziemer, Burkhard,Siemons, Maike,Simon, Ulrich
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- Stability and toxicity of tris-tolyl bismuth(v) dicarboxylates and their biological activity towards Leishmania major
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A series of 29 tris-tolyl bismuth(v) di-carboxylato complexes of composition [Bi(Tol)3(O2CR)2] involving either ortho, meta or para substituted tolyl ligands have been synthesized and characterised. Of these 15 were assessed for their toxicity towards Leishmania promastigotes and human fibroblast cells, with ten then being subsequently assessed against parasite amastigotes. The carboxylate ligands are drawn from a series of substituted and biologically relevant benzoic acids which allow a comparison with earlier studies on [BiPh3(O2CR)2] and analogous Sb(v) [SbAr3(O2CR)2] (Ar = Ph and Tol) complexes. Twelve complexes have been structurally characterized by single crystal X-ray diffraction and shown to adopt a typical trigonal bipyramidal geometry in which the three tolyl ligands occupy the equatorial plane. NMR studies on two illustrative examples indicate that the complexes are stable in D2O and DMSO but only have a half-life of 1.2 hours in culture medium, with glucose being a contributing factor in decomposition and reduction to Bi(Tol)3. Despite their short lifetime many complexes show significant toxicity towards promastigotes at low concentration (3(O2CC6H3(2-OH,5-C6H3(2,4-F2)))2] and 838 for [Bi(m-Tol)3(O2CC6H4(2-OAc))2]. Best activity and selectivity is observed with complexes containing o- and m-tolyl ligands, and it appears the primary influence on fibroblast toxicity is the Ar ligand while the carboxylate influences promastigote toxicity. The complexes are less effective in vitro against the parasite amastigotes, where longer incubation times and harsher chemical and biological environments are encountered in the assay. Nevertheless, there were some statistically relevant differences at 1 μM against the positive controls with the best performing complexes being [Bi(o-Tol)3(O2CC6H4(2-EtO))2] and [Bi(m-Tol)3(O2CC6H4(2-OAc))2].
- Ong, Yih Ching,Blair, Victoria L.,Kedzierski, Lukasz,Tuck, Kellie L.,Andrews, Philip C.
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- Palladium(II)-catalyzed aryl coupling of triarylbismuthines under air
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Triarylbismuthines readily reacted with a catalytic amount of palladium(II) acetate in methanol under air to give the corresponding biaryls in high yields. The presence of oxygen was indispensable for this catalytic coupling, biaryl formation being quite slow under nitrogen. Oxygen absorption was observed during the reaction and a Pd-oxygen complex prepared separately worked effectively as a reagent for this coupling even under inert gas.
- Ohe, Toshiyuki,Tanaka, Takumi,Kuroda, Masashi,Cho, Chan Sik,Ohe, Kouichi,Uemura, Sakae
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- Synthesis of highly functionalized triarylbismuthines by functional group manipulation and use in palladium- and copper-catalyzed arylation reactions
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Organobismuthines are an attractive class of organometallic reagents that can be accessed from inexpensive and nontoxic bismuth salts. Triarylbismuthines are particularly interesting due to their air and moisture stability and high functional group tolerance. We report herein a detailed study on the preparation of highly functionalized triarylbismuth reagents by triple functional group manipulation and their use in palladium- and copper-catalyzed C-, N-, and O-arylation reactions.
- Hébert, Martin,Petiot, Pauline,Benoit, Emeline,Dansereau, Julien,Ahmad, Tabinda,Le Roch, Adrien,Ottenwaelder, Xavier,Gagnon, Alexandre
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p. 5401 - 5416
(2016/07/13)
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- Synthesis of highly functionalized diaryl ethers by copper-mediated O-arylation of phenols using trivalent arylbismuth reagents
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Highly functionalized diaryl ethers were prepared by copper(II) acetate mediated O-arylation reaction of phenols using trivalent organobismuthanes. The reaction is performed under simple conditions and tolerates a wide diversity of functional groups on the phenol and on the organobismuth reagent. Substoichiometric amounts of catalyst can be used by performing the reaction under an oxygen atmosphere. The N-arylation of pyridones is also reported. Highly functionalized diaryl ethers were prepared by a copper(II) acetate mediated O-arylation reaction of phenols using trivalent organobismuthanes (see scheme). The reaction is performed under simple conditions and tolerates a wide diversity of functional groups on the phenol and on the organobismuth reagent. Substoichiometric amounts of catalyst can be used by performing the reaction under an oxygen atmosphere. The N-arylation of pyridones is also reported. FG=functional group.
- Crifar, Cynthia,Petiot, Pauline,Ahmad, Tabinda,Gagnon, Alexandre
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p. 2755 - 2760
(2014/03/21)
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- Palladium-catalyzed cross-coupling reaction of functionalized aryl- and heteroarylbismuthanes with 2-halo(or 2-Triflyl)azines and -diazines
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The palladium-catalyzed cross-coupling of highly functionalized organobismuthanes with 2-halo(or 2-triflyl)pyridines, -pyrimidines, -pyrazines, and -pyridazines is reported. The reaction tolerates numerous functional groups, including aldehydes. The synthesis of a shelf-stable (formylphenyl)bismuth reagent and its use in a cross-coupling reaction is also described. The palladium-catalyzed cross-coupling of highly functionalized organobismuthanes with 2-halo(or 2-triflyl)pyridines, -pyrimidines, -pyrazines, and -pyridazines is reported. The reaction tolerates numerous functional groups, including aldehydes. The synthesis of a shelf-stable (formylphenyl)bismuth reagent and its use in cross-coupling reactions is also described. Copyright
- Petiot, Pauline,Gagnon, Alexandre
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supporting information
p. 5282 - 5289
(2013/09/02)
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- Diverse structures and remarkable oxidizing ability of triarylbismuthane oxides. Comparative study on the structure and reactivity of a series of triarylpnictogen oxides
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A systematic series of triarylbismuthane oxides was prepared in order to disclose their structure and reactivity, which have been compared with those of lighter pnictogen counterparts. X-ray crystallographic analysis of tris(2-methoxyphenyl)bismuthane oxide and tris(2-methoxyphenyl)stibane oxide revealed that they exist as dimers with a flat bis(a-oxo) ring, implying that the polarized Bi+-O- and Sb+-O- bonds aggregate to attain electrostatic stabilization. In sharp contrast to their phosphorus, arsenic, and antimony counterparts, triarylbismuthane oxides are thermally unstable and possess a high oxidizing ability. In particular, the bismuthane oxides bearing ortho-substituted aryl ligands oxidized primary and secondary alcohols to aldehydes and ketones, respectively, with high efficiency under mild conditions.
- Matano, Yoshihiro,Nomura, Hazumi,Hisanaga, Teppei,Nakano, Haruyuki,Shiro, Motoo,Imahori, Hiroshi
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p. 5471 - 5480
(2008/10/09)
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- Synthesis, structure, and reactions of (acylimino)triaryl-λ5-bismuthanes: First comparative study of the (acylimino)pnictorane series
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The synthesis, structure, and reactions of (acylimino)triaryl-λ5-bismuthanes and a comparative study of the structure and reactivity of a series of (acylimino)pnictoranes are reported. Treatment of ortho-substituted triarylbismuth dichlorides 1 (Ar3BiCl2; Ar = 2-MeC6H4, 2-MeOC6H4, 2,4,6-Me3C6H2) with amides 2 (H2-NCOR; R = CF3, CCl3, 3,5-(CF3)2C6H3) in the presence of 2.2 equiv of KO-t-Bu in dichloromethane afforded (acylimino)triaryl-λ5-bismuthanes 3 (Ar3Bi=NCOR) in yields of 77-96%. The ortho-substituted aryl ligands and the electron-withdrawing N-substituents afford kinetic and thermodynamic stabilization, respectively, to the reactive Bi=N bond. The structures and properties of a series of (acylimino)pnictoranes (Ar3M=NCOR and H3M=NCOCF3; M = P, As, Sb, Bi) are compared by IR and 13C and 15N NMR, X-ray crystallography, and ab initio molecular orbital calculations. It was found that the contribution of the M+-N=C-O- canonical form becomes more prominent and the single-bond character of the M=N bond increases progressively as the pnictogen atom becomes heavier. The Bi=N bond of (acylimino)-λ5-bismuthanes 3 possesses a highly polarized single-bond character, probably due to the differences in orbital size and electronegativity between the bismuth and nitrogen atoms. Thermal decomposition of (aroylimino)triaryl-λ5-bismuthane 3f (o-Tol3Bi=NCOAr; Ar = 3,5-(CF3)2C6H3) produces a gel in dry conditions or aniline 12 (ArNH2) in slightly wet conditions with a good recovery of tris(2-methylphenyl)bismuthane (4a). It is likely that the aryl isocyanate 13 (ArNCO) is produced during the thermolysis via a concerted C → N migration of the Ar group with an elimination of the triarylbismuthonio group as bismuthane 4a. (Acylimino)triaryl-λ5-bismuthanes 3 oxidize 1,1,2,2-tetraphenylethanediol, benzenethiol, methanol, and ethanol to benzophenone, diphenyl disulfide, methyl formate, and acetaldehyde, respectively, in two different reaction pathways depending on the structure of the substrates. Compound 3d (o-Tol3Bi=NCOCCl3) transfers the nitrenoid moiety to triphenylphosphane, triphenylarsane, and tris(2-methylphenyl)stibane to give the corresponding (acylimino)pnictoranes (Ar3M=NCOCl3; M = P, As, Sb) and 4a, suggesting that 3d is thermodynamically much less stable than their lighter pnictogen counterparts. The copper-catalyzed decomposition of 3 (o-Tol3Bi=NCOR) afforded N-acyl-o-toluidines 18 (o-TolNHCOR) via a Bi → N migration of the tolyl group. The observed reactivities of (acylimino)triaryl-λ5-bismuthanes 3 demonstrate a good leaving ability of the bismuthonio group.
- Matano,Nomura,Suzuki,Shiro,Nakano
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p. 10954 - 10965
(2007/10/03)
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- Stabilized bismuthonium ylides bearing a highly cross-conjugated ylidic carbon atom: Synthesis, structures, and reactions
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The reaction of iminotriaryl-λ5-bismuthanes (2; Ar3Bi=NR; R = COR″ or SO2R″) with dialkyl acetylenedicarboxylates (3; R′O2CC≡CCO2R′) has been found to afford highly stabilized bismuthonium ylides (4;
- Matano, Yoshihiro,Nomura, Hazumi,Suzuki, Hitomi
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- First synthesis, structure, and reactivity of (acylimino)triaryl-λ5-bismuthanes stabilized by ortho-substituted aryl ligands
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The reactive Bi(V)=N bond in (acylimino)-triaryl-λ5-bismuthanes has been found to be stabilized effectively by ortho-substituted aryl ligands such as o-tolyl, o-anisyl, and mesityl groups. These imino-λ5-bismuthanes, in which the bismuth center possesses a distorted tetrahedral geometry, behave as a nitrene precursor as well as an oxidizing agent, depending on the substrates and conditions.
- Matano, Yoshihiro,Nomura, Hazumi,Shiro, Motoo,Suzuki, Hitomi
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p. 2580 - 2582
(2008/10/08)
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- Fourier-transform Raman and infrared spectra and normal coordinate analysis of the triphenyl compounds and their methyl-, methoxy- and fluoro-substituted derivatives of arsenic, antimony and bismuth
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The Fourier transform (FT)-Raman and infrared (IR) spectra of triphenyl-, perdeuterated triphenyl-, tris(2-methylphenyl)-, tris(3-methylphenyl)-, tris(2,4,6-trimethylphenyl)-, tris(2-methoxyphenyl)-, tris(3-methoxyphenyl)-, tris(3-fluorophenyl)- and tris(
- Ludwig,Dolny,Goetze
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p. 2363 - 2372
(2007/10/03)
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