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François Mathey

Publications and source records attributed to François Mathey.

At least 19 recordsLinked to original sources
PubMed2005

2-Bromophospholide ions: synthesis and theoretical study.

DFT calculations at the B3 LYP/6-311++G(3df,2p) level indicate that the 2-bromophospholide ion could be stable toward self-arylation as a result of the lowered nucleophilicity of the in-plane phosphorus lone pair (the corresponding sigma(P) orbital is lowered by 0.7 eV compared with the corresponding orbital of the parent phospholide ion, and the negative charge at P is reduced from -0.435 to -0.369 e). Accordingly, the synthesis of 2-bromo-3,4-dimethylphospholide was successfully carried out by quantitative base-induced dealkylation of 2-bromo-1-(2-ethoxycarbonylethyl)-3,4-dimethylphosphole. This ion reacts with FeCl2 to give the corresponding 2,2'-dibromo-3,3',4,4'-tetramethyl-1,1'-diphosphaferrocene as a poorly stable mixture of meso- and rac-diastereomers in 18% yield.

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PubMed2005

A straightforward synthesis of 3-acylphospholes.

[structure: see text] The reaction of 2,5-diphenylphospholide, first with acyl chlorides, then with tBuOK, provides a direct access to 3-acyl-2,5-diphenylphospholides via a 1H-, 2H-, 3H-phosphole equilibrium.

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PubMed2005

Synthesis and properties of [NiCp*(2,5-tBu2PC4H2)], a 20-valence-electron phosphanickelocene.

The reaction of the bulky phospholide salt Li(2,5-tBu2PC4H2) x 2THF (1; THF = tetrahydrofuran) with [NiCp*(acac)] (HCp* = pentamethylcyclopentadiene, Hacac = acetylacetone) gives the green air-sensitive phosphanickelocene [NiCp*(2,5-tBu2PC4H2)] (2) in yields of about 85%. An X-ray structural determination of 2 shows long Ni-ring bonds and "delocalised" ring P-C and C-C bonds characteristic of a classical 20-valence-electron (ve) nickelocene. The electronic structure of 2 has been clarified through a combined Amsterdam density functional (ADF) and photoelectron spectroscopic study, which indicates that the higher lying semi-occupied molecular orbital (SOMO) (-5.82 eV) has a' symmetry and that the phosphorus "lone pair" is energetically low-lying (-8.15 eV). Oxidation of phosphanickelocene 2 by AgBF4 occurs quantitatively to give the corresponding air-sensitive orange phosphanickelocenium salt [NiCp*(2,5-tBu2PC4H2)][BF4] (3). This complex has also been characterised by an X-ray crystallographic study, which reveals long Ni-C(alpha) and short C(alpha)-C(beta) bonds in the phospholyl ligand indicative of a SOMO having a'' symmetry. PMe3 reacts with 2 at room temperature to provoke a ring-slip reaction that gives the 18ve complex [NiCp*eta1-(2,5-tBu2PC4H2)(PMe3)] (4), but shows no reaction with the phosphanickelocenium salt 3 under the same conditions.

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PubMed2004

A theoretical study of the formation of phosphaacetylene by thermolysis of triallylphosphine.

A theoretical study of the decomposition of triallylphosphine into phosphaacetylene at the B3LYP/6-311++G(3df,2p) level has shown that the most likely mechanism involves two retroene eliminations of propene leading to vinylphosphaacetylene. Two mechanisms can account for the formation of HCP from vinylphosphaacetylene, either by a 1,2 or a 1,3 hydrogen shift. The first pathway was found to be the most favored kinetically. It is quite similar to the pathway proposed for the thermal decomposition of vinylacetylene into acetylene in the shock tube.

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PubMed2004

Transient 2H-phospholes as powerful synthetic intermediates in organophosphorus chemistry.

Transient 2H-phospholes are easily obtained from 1-R-1H-phospholes by a [1,5]-shift of the R-substituent from phosphorus to the alpha-carbons of the ring. They display cyclopentadiene-like chemistry: [4+2]-cycloaddition reactions with alkenes, alkynes, conjugated dienes and aldehydes, deprotonation to give the aromatic phospholide ions, and reaction with transition metal derivatives to give eta(5)-phospholyl complexes. The resulting products have found some use in homogeneous and asymmetric catalysis and show some promise in the field of electroconducting polymers.

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PubMed2003

Synthesis and properties of [CoCp*(2,5-PC4tBu2H2)]: the first monophosphacobaltocene.

The reduction of the phosphacobaltocenium salt [CoCp*(2,5-PC(4)tBu(2)H(2))](+)[BPh(4)](-) (3; Cp*=pentamethylcyclopentadienyl) by magnesium in tetrahydrofuran (THF) furnishes the stable air-sensitive phosphacobaltocene [CoCp*(2,5-PC(4)tBu(2)H(2))] (4) in yields of up to 80 %. The crystal structure of 4 shows long Co-C(alpha) and short C(alpha)-C(beta)bonds in the phospholyl ligand, consistent with a semi-occupied molecular orbital (SOMO) having a" symmetry. A combined Amsterdam density functional (ADF)/photoelectron spectroscopic study, which confirms this assignment, gives ionisation energies (IE) of 5.02 eV from the SOMO and 8.89 eV from the phosphorus "lone pair". A comparison of cyclovoltammograms for 3 and the corresponding cyclopentadienyl complex [CoCp*(1,3-C(5)tBu(2)H(3))](+) [BPh(4)](-)(5) shows that replacing a CH group by an sp(2) phosphorus atom results in an anodic first reduction potential shift of 0.29 V.

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PubMed2003

Phospha-organic chemistry: panorama and perspectives.

Since the beginning of the seventies, organophosphorus chemistry has been completely rejuvenated by the discovery of stable derivatives in which phosphorus has the coordination numbers one or two. The chemistry of these compounds mimics the chemistry of their all-carbon analogues. In this Review article this analogy is discussed for the phosphorus counterparts of alkenes, alkynes, and carbenes. In each case, the synthesis, reactivity, and coordination modes are briefly examined. Some special electronic configurations are also discussed, which include one-electron Pbond;P bonds, strained bonds, and aromatic systems. To conclude, some potential applications of this chemistry in the areas of molecular materials and homogeneous catalysis are presented.

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PubMed2003

Hetero-Diels-Alder reactions of 2H-phospholes with aldehydes.

Transient 2-phenyl-3,4-dimethyl-5H-phosphole reacts at 150 degrees C with aldehydes RCH=O to give the corresponding [4 + 2] P-O cycloadducts with endo- (major) and exo-R-substituents. The cycloaddition with alpha,beta-unsaturated aldehydes takes place both at the C=O (major) and C=C bonds. Upon heating under reduced pressure, the benzaldehyde cycloadduct dissociates to give back the 2H-phosphole, which either dimerizes, is trapped by diphenylacetylene, or is deprotonated by (t)BuOK.

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PubMed2002

Dianionic platinadiphospholene complexes.

1,2,3,4-tetraphenyl-1,2-dihydrodiphosphetene 1 reacts with lithium or sodium naphthalenide to afford the corresponding dianionic salts 2 and 3. An X-ray crystal structure analysis shows that dianion 3 of general formula [(1)2-2Na3(DME)2, Na(DME)3] is a polymeric structure consisting of [(1)2-2Na3(DME)2] units which are connected together through one sodium atom. Reaction of the dianionic lithium salt 2 with [Pt(COD)Cl2] affords the 4[Li(2.2.1)]2 complex, after the addition of 2 equiv of (2.2.1) cryptate. The overall geometry around platinum in 4[Li(2.2.1)]2 can be described as distorted square planar, and only the diastereomer (1-R, 2-S, 3-R, 4-S) is formed. X-ray data indicate that no delocalization takes place within each platinadiphospholene unit and that complex 4[Li(2.2.1)]2 must be regarded as the coordination of two molecules of dianion 2 onto a Pt2+ center. Reaction of the dianionic sodium salt 3 with 1 equiv of [Pt(COD)Cl2] produces the 4[Na(DME,Et2O)]2 complex which adopts a pseudotetrahedral geometry around platinum ( between interplane angles = 35), the two cationic units [Na(DME, Et2O)] being located along a C2 axis. Four weak interactions exist between the sodium cations and the phosphorus atoms. Only the (1-S, 2-S, 3-S, 4-S) diastereomer is formed. Bond distances in the diphospholene units of 4[Na(DME,Et2O)]2 are close to that of dianion 3 indicating that, like in 4[Li(2.2.1)]2, the complex can be described as a platinum (+2) dianionic species.

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PubMed2002

Synthesis of phosphole-2,5-dicarboxylic acids via a [1,5]-shift of carbon dioxide around the phosphole nucleus.

A new methodology for the synthesis of 1-P-functionalized phosphole-2,5-dicarboxylic acids is described. The carboxylic group is introduced through a two-step sequence which involves a preliminary attack of the phospholide unit onto CO(2) followed by a [1,5]-shift reaction of the CO(2)Li group around the phosphole nucleus. This approach was extended to the preparation of a new type of bidentate ligands. [reaction: see text]

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PubMed2002

Synthesis of the first 1,2,3,4-azatriphospholene complex.

Synthesis of the first 1,2,3,4-azatriphospholene complex was achieved by heating a solution of a P-phenyl-substituted 7-phosphanorbornadiene tungsten complex and triphenylphosphonio cyanomethylide, whereby CH-insertion products were formed in a competing reaction; these results also provide first evidence for the ability of electrophilic terminal phosphanediyl complexes to react at the ylide carbon atom and at the carbonitrile nitrogen atom of Wittig-ylides having a nitrile functional group; the structures of both complexes were established through X-ray single-crystal diffraction studies.

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