Hybrid molecular systems containing tetrathiafulvalene and iron-alkynyl electrophores : five-component functional molecules obtained from C-H bond activation. - Université de Rennes Accéder directement au contenu
Article Dans Une Revue Chemistry - A European Journal Année : 2013

Hybrid molecular systems containing tetrathiafulvalene and iron-alkynyl electrophores : five-component functional molecules obtained from C-H bond activation.

Yoshiyuki Ogyu
  • Fonction : Auteur
Yuki Kumamoto
  • Fonction : Auteur
Akira Miyazaki
  • Fonction : Auteur
Lahcène Ouahab
  • Fonction : Auteur
  • PersonId : 943424
Karine Costuas
Claude Lapinte
  • Fonction : Auteur
  • PersonId : 941302

Résumé

Treatment of [Cp*(dppe)Fe-C≡C-TTFMe3] (1) with Ag[PF6] (3 equiv) in DMF provides the binuclear complex [Cp*(dppe)Fe=C=C=TTFMe2 =CH-CH=TTFMe2 =C=C=Fe(dppe)Cp*][PF6]2 (2[PF6 ]2) isolated as a deep-blue powder in 69 % yield. EPR monitoring of the reaction and comparison of the experimental and calculated EPR spectra allowed the identification of the radical salt [Cp*(dppe)Fe=C=C=TTFMe2 =CH][PF6]2 ([1-CH][PF6]) an intermediate of the reaction, which results from the activation of the methyl group attached in vicinal position with respect to the alkynyl-iron on the TTF ligand by the triple oxidation of 1 leading to its deprotonation by the solvent. The dimerization of [1-CH][PF6] through carbon-carbon bond formation provides 2[PF6]2. The cyclic voltammetry (CV) experiments show that 2[PF6]2 is subject to two sequential well-reversible one-electron reductions yielding the complexes 2[PF6] and 2. The CV also shows that further oxidation of 2[PF6]2 generates 2[PF6]n (n=3-6) at the electrode. Treatment of 2[PF6]2 with KOtBu provides 2[PF6] and 2 as stable powders. The salts 2[PF6] and 2[PF6]2 were characterized by XRD. The electronic structures of 2(n+) (n=0-2) were computed. The new complexes were also characterized by NMR, IR, Mössbauer, EPR, UV/Vis and NIR spectroscopies. The data show that the three complexes 2[PF6]n are iron(II) derivatives in the ground state. In the solid state, the dication 2(2+) is diamagnetic and has a bis(allenylidene-iron) structure with one positive charge on each iron building block. In solution, as a result of the thermal motion of the metal-carbon backbone, the triplet excited state becomes thermally accessible and equilibrium takes place between singlet and triplet states. In 2[PF6], the charge and the spin are both symmetrically distributed on the carbon bridge and only moderately on the iron and TTFMe2 electroactive centers.

Dates et versions

hal-00822744 , version 1 (15-05-2013)

Identifiants

Citer

Frederic Justaud, Frédéric Gendron, Yoshiyuki Ogyu, Yuki Kumamoto, Akira Miyazaki, et al.. Hybrid molecular systems containing tetrathiafulvalene and iron-alkynyl electrophores : five-component functional molecules obtained from C-H bond activation.. Chemistry - A European Journal, 2013, 19 (18), pp.5742-57. ⟨10.1002/chem.201204227⟩. ⟨hal-00822744⟩
87 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More