Straightforward Access to Stable, 16-Valence-Electron Phosphine-Stabilized Fe Olefin Complexes and Their Reactivity

Benjamin Burcher (1) , Kevin J Sanders (2) , Ladislav Benda (2) , Guido Pintacuda (2) , Erwann Jeanneau (3) , Andreas A. Danopoulos (4) , Pierre Braunstein (4) , Hélène Olivier-Bourbigou (1) , Pierre-Alain Breuil (1)

1 IFPEN - IFP Energies nouvelles
2 Biological Solid-State NMR Methods - Méthodes de RMN à l'état solide en biologie
3 UCBL - Université Claude Bernard Lyon 1
4 Institut de Chimie de Strasbourg

The use of the dialkene divinyltetramethyldisiloxane (dvtms) allows easy access to the reactive 16-valence-electron complexes [Fe-0 (L-L(dvtms)] (L-L = dppe (1,2-bis-(diphenylphosphino)ethane; 1), dppp (1,2-bis(diphenylphOsphino)-propane; 2), pyNMe:P('Pr)(2) (N-(diisopropylphosphino)-N-methylpyridin-2-amine; 4), dipe (1,2-bis(diisopropylphosphino)ethane; 5)) and [Fe-0(L)(2)(dvtms)] (L = PMe3; 3) by a mild reductive route using AlEt2(OEt) as reducing agent. In contrast, by the "same methodology, the 18-valence-electron complexes [Fe-0(L-L)2(ethylene)] (L-L = dppin (1,2-bis(diphenylphosphino)methane; 6),.dppa (1,2-bis-(diphenylphosphino)amine; 7), dppe (8)) were obtained, Which do not contain dvtms. In addition, a combined DFT and solid-state paramagnetic NMR methodology is introduced for the structure determination of 5. A comparative study of the reactivity of 1, 2, 4-6, and 8 with 3-hexyne highlights emerging mechanistic implications for C C coupling reactions using these complexes as catalysts.

Mots clés: ELECTRON-PARAMAGNETIC-RESONANCE; LOW-COORDINATE IRON; SOLID-STATE NMR; MULTIVINYLSILICON LIGANDS; DINITROGEN COMPLEXES; UNACTIVATED ALKENES; TRANSITION-METALS; ADIABATIC PULSES; EPR PARAMETERS; PI-COMPLEXES

Domaines: Chimie de coordination

Benjamin Burcher, Kevin J Sanders, Ladislav Benda, Guido Pintacuda, Erwann Jeanneau, et al.. Straightforward Access to Stable, 16-Valence-Electron Phosphine-Stabilized Fe Olefin Complexes and Their Reactivity. Organometallics, 2017, 36 (3), pp.605-613. ⟨10.1021/acs.organomet.6b00803⟩. ⟨hal-01503473⟩