33519-69-6Relevant academic research and scientific papers
Formation of the Alkoxyalkyl Complexes (CO)2(η-C5H4R)> (M = Mo, R = H; M = W, R = H or Me) and their Transformations by Loss of MeOH into η3-Propenoyl or Vinyl Complexes. Crystal Structures of (CO)2(PPh3)(η-C5H5>BF4, 3-CH2CHC=O)(CO)(PPh3)(η-C5...
Adams, Harry,Bailey, Neil A.,Gauntlett, J. Trevor,Harkin, Ian M.,Winter, Mark J.,Woodward, Simon
, p. 1117 - 1128 (2007/10/02)
Addition of MeSO3F or BF4 followed by PPh3 to the aldehyde complex (1-) results in formation of the methoxyalkyl complex trans-(CO)2(PPh3)(η-C5H5)> in a reaction that proceeds via the unstable 3-CHMe(OMe)>(CO)2(η-C5H5)>.A by-product of this reaction is the ylide trans-(CO)2(PPh3)(η-C5H5)>X (X = BF4(1-) or SO3F(1-)), a species (X = BF4) better prepared by treatment of trans-(CO)2(PPh3)(η-C5H5)> with HBF4 in the presence of PPh3.The crystalline ylide trans-(CO)2(PPh3)(η-C5H5)>BF4 is monoclinic, with a = 11.378(34), b = 18.903(35), c = 20.17(8) Angstroem, β = 115.28(31) deg and for the 3918 independent reflections with I/?(I) > 3.0, R = 0.0510.In solution, trans-(CO)2(PPh3)(η-C5H5)> either degrades to or loses MeOH to form the η3-propenoyl 3-CH2CHC=O)(CO)(PPh3)(η-C5H5)>.This molecule is monoclinic, with a = 17.231(50), b = 8.189(14), c = 16.727(36) Angstroem, β = 106.79(22) deg and for the 1654 independent reflections for which F/?(F) > 4.0, R = 0.100.The proposed mechanism for its formation is based on isotopic tracking experiments and includes a vinyl to carbonyl migration.Treatment of (R = H or Me) with PPh3 in MeCN gives the acyl .These react with to form the cationic carbenes (CO)2(PPh3)(η-C5H4R)>BF4, which in turn react with LiBHEt3 to give the alkoxyalkyls trans-(CO)2(PPh3)(η-C5H4R)>.The alkoxyalkyls trans-(CO)2(PPh3)(η-C5H4R)> react with traces of acid to form the ?-vinyls trans-, the methylcyclopentadienyl species of which is crystalline, monoclinic, with a = 36.952(40), b = 10.971(13), c = 25.148(23) Angstroem and β = 103.60(8) deg.For the 2542 independent reflections for which F/?(F) > 5.0, R converged to 0.0750.
Synthesis and thermolysis of neutral metal formyl complexes of molybdenum, tungsten, manganese, and rhenium
Gibson,Owens,Mandal,Sattich,Franco
, p. 498 - 505 (2008/10/08)
The possible intermediacy of catalyst-bound formyls in syngas transformations has prompted efforts to prepare and study the chemistry of transition-metal formyl complexes over more than a decade. We have used a mild borohydride in our reactions with metal carbonyl cations and have introduced some variations into the syntheses which allow, in almost all cases, for the pure formyl complex to be precipitated from solution as it is formed. The formyl complexes and their cationic precursors are shown. Seven of the formyls are new; improved procedures have been established for the other four. All but one of the compounds have been isolated.
SYNTHESIS OF ALLYL-TRANSITION METAL COMPLEXES BY PHASE TRANSFER CATALYZED REACTIONS OF METAL CARBONYL HALIDES. III. CONSIDERATIONS OF THE MECHANISMS
Gibson, Dorothy H.,Hsu, Wen-Liang,Ahmed, Fahim U.
, p. 379 - 401 (2007/10/02)
Mechanisms are proposed for the hydroxide ion-initiated reactions of metal carbonyl halides which lead to allyl-transition metal complexes under phase transfer conditions.Evidence is presented for intermediate anionic metallocarboxylic acids in reactions leading to η3-allyl products of molybdenum, iron, ruthenium and magnanese, whereas η1 complexes are shown to result from halide displacement reactions in which simple metal carbonyl anions are generated.In some cases phosphorus-containing ligands inhibit the hydroxide-promoted reactions of metal carbonyl halideswith allyl bromide; a rationale involving decreased acidity of the carbonyl ligands is presented. syntheses of η3-C3H5Mn(CO)3P(OCH3)3 and η3-C3H5Mn(CO)22 by phase transfer catalysis are also described.
