0000000000160732
AUTHOR
Philippe Sauvageot
Tantalocenehydridephosphorus chemistry.
Abstract The aim of this paper is to look for a better knowledge of the behaviour of bent tantalocenes that bear hydrides, phosphorus PR2X (R=Me, Ph; X=H, lone pair) and cyclopentadienyl (Cp=C5H5, Cp′=C5H2tBu(Me)2, Cp*=C5Me5) ligands. An orbital control of regioselectivity of insertion of the PR2 phosphide fragment of chlorophosphines PR2Cl into the central TaH bond of trihydrides Cp2TaH3 leading to the formation of metallophosphonium cations is discussed. Neutralisation of cationic complexes with strong bases leads either to the Ta(V)–phosphide or to the Ta(III)–phosphine species depending on the nature of the cyclopentadienyl ligand; good electron donor Cp′ and Cp* rings favour the forma…
Desulfurization and ring opening of thiirane induced by tantalocene trihydride complexes: Synthesis, reactivity and X-ray structure of Cp′2Ta(=S)(S-iPr) with Cp′=η5-C5H4tBu
The reaction of the tantalocene trihydride complexes Cp′ 2 TaH 3 1 (Cp′= η 5 -C 5 H 4 t Bu) or Cp″CpTaH 3 1′ (Cp″= η 5 -C 5 H 2 -1,2-Me 2 -4- t Bu) with propylene sulfide was found to proceed via an unprecedented sulfur transfer and regioselective ring opening reaction at once to yield sulfido-thiolato tantalocene complexes Cp′ 2 Ta(S)(S- i Pr) 2a whose structure has been determined by X-ray crystallography or Cp″CpTa(S)(S- i Pr) 2′a . Complex 1 reacts with ethylene sulfide to give Cp′ 2 Ta(S)(S–Et) 2b . The reactivity of 2a towards a variety of electrophilic moities has been investigated: protonation (with HBF 4 ) and alkylation (with MeI) reactions occur at the terminal sulfur ligand, …
New insights into the reactivity of the tantalocene hydride Cp′2TaH3 (Cp′=η5-tBuC5H4). Synthesis and characterisation of cationic Ta(V) complexes with 0,0 and S,N chelating ligands
Abstract Reaction of various neutral LXH bidentate ligands (2-aminobenzoic acid, acetylacetone, dibenzoylmethan and 2-aminobenzenethiol) with [Cp′2TaH2]+, obtained in situ from Cp′2TaH3 treated with triphenylmethan cation, affords after dihydrogen elimination the corresponding cationic species [Cp′2Ta(H)(LX)]+ in BF4 or PF6 salts. Complexes [Cp′2TaH(η2-O2CC6H4-o-NH2O,O′)]PF6 (3), {Cp′2Ta[η2-OC(Me)CHC(Me)OO,O′]}BF4 (4a), {Cp′2TaH[η2-OC(Ph)CHC(Ph)OO,O′]}BF4 (4b) and [Cp′2TaH(η2-SC6H4-o-NH2S,N)]PF6 (5) are characterised by analytical and spectroscopic methods. With thiopyridine, the kinetic (6) and the thermodynamic (6′) isomers [Cp′2TaH(η2-2-SC5H4NS,N)]PF6 are identified. Crystal struc…
Formation and Reactivity of the [Cp‘2Ta(H)2]+ Cation (Cp‘ = η5-tBuC5H4)
The complex Cp‘2Ta(H)(OCOCF3)2 (2) is synthesized by the acidolysis of Cp‘2TaH3 (1) (Cp‘ = η5-tBuC5H4) in the presence of an excess of trifluoroacetic acid. 1 undergoes a loss of H- upon the reacti...
Réactivité d'hydrures de tantalocène : insertion du soufre dans la liaison tantale-hydrogène
Resume La recherche entreprise sur la reactivite des hydrures de tantalocene avec le soufre elementaire nous amene a la synthese de complexes monosoufres par une reaction d'insertion du soufre dans la liaison Ta-H. Des informations sont apportees sur le mecanisme de la formation de complexes a ligand (η2-S2) et la synthese du complexe Cp′2Ta(CO)(SH) est decrite.