Chemistry and electrochemistry of the heterodinuclear complex ClPd(dppm)(2)PtCl: A M-M ' bond providing site selectivity - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Inorganic Chemistry Année : 2006

Chemistry and electrochemistry of the heterodinuclear complex ClPd(dppm)(2)PtCl: A M-M ' bond providing site selectivity

Résumé

he heterodinuclear d(9)-d(9) title compound 1, whose crystal structure has been solved, reacts with dppm [bis(diphenylphosphino)methane] in the presence of NaBF4 to generate the salt [ClPd(mu-dPPM)(2)Pt(eta(1)-dppm)][BF4] (2a), which contains a Pt-bound dangling dppm ligand. 2a has been characterized by H-1 and P-31 NMR, Fourier transform Raman [v(Pd-Pt) = 138 cm(-1)], and UV-vis spectroscopy [lambda(max)(d sigma-d sigma*) = 366 nm]. In a similar manner, [ClPd(mu-dppm)(2)Pt(eta(1)-dppm=O)][BF4] (2b), ligated with a dangling phosphine oxide, has been prepared by the addition of dppm=O. The molecular structure of 2b has been established by an X-ray diffraction study. 2a reacts with 1 equiv of NaBH4 to form the platinum hydride complex [(eta(1)-dppm)Pd(mu-dppm)(2)Pt(H)][BF4] (3). Both 2a and 3 react with an excess of NaBH4 to provide the mixed-metal d(10)-d(10) compound [Pd(mu-dppm)(3)Pt] (4). The photophysical properties of 4 were studied by UV-vis spectroscopy [lambda(max)(d sigma-d sigma*) = 460 nm] and luminescence spectroscopy (lambda(emi) = 724 nm; tau(e) = 12 +/- 1 mu s, 77 K). The protonation of 1 and 4 leads to [ClPd(mu-dppm)(2)(mu-H)PtCl](+) (5) and 3, respectively. Stoichiometric treatment of 1 with cyclohexyl or xylyl isocyanide yields [CIPd(mu-dppm)(2)Pt(CNC6H11)]Cl (6a) and [ClPd(mu-dppm)(2)Pt(CN-xylyl)]Cl (6b) ligated by terminal-bound CNR ligands. In contrast, treatment of 1 with the phosphonium salt [C&3bond; NCH2PPh3]Cl affords the structurally characterized A-frame compound [ClPd(mu-dppm)(2)(mu-C=NCH2PPh3)PtCl]Cl (6c), spanned by a bridging isocyanide ligand. The electrochemical reduction of 2a at -1.2 V vs SCE, as well as the reduction of 5 in the presence of dppm, leads to a mixture of products 3 and 4. Further reduction of 3 at -1.7 V vs SCE generates 4 quantitatively. The reoxidation at 0 V of 4 in the presence of Cl- ions produces back complex 2a. The whole mechanism of the reduction of 1 has been established.

Dates et versions

hal-00475281 , version 1 (21-04-2010)

Identifiants

Citer

David Evrard, Sébastien Clément, Dominique Lucas, Bernard Hanquet, Michael Knorr, et al.. Chemistry and electrochemistry of the heterodinuclear complex ClPd(dppm)(2)PtCl: A M-M ' bond providing site selectivity. Inorganic Chemistry, 2006, 45 (3), pp.1305-1315. ⟨10.1021/ic051102z⟩. ⟨hal-00475281⟩
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