Chemistry and Electrochemistry of the Heterodinuclear Complex ClPd(dppm)2PtCl: A M-M' Bond Providing Site Selectivity
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- 作者：David Evrard ; Sé ; bastien Clé ; ment ; Dominique Lucas ; Bernard Hanquet ; Michael Knorr ; Carsten Strohmann ; Andreas Decken ; Yves Mugnier ; and Pierre D. Harvey
- 刊名：Inorganic Chemistry
- 出版年：2006
- 出版时间：February 6, 2006
- 年：2006
- 卷：45
- 期：3
- 页码：1305 - 1315
- 全文大小：233K
- 年卷期：v.45,no.3(February 6, 2006)
- ISSN：1520-510X
文摘
The heterodinuclear d9-d9 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(
-dppm)2Pt(
1-dppm)][BF4] (2a),which contains a Pt-bound dangling dppm ligand. 2a has been characterized by 1H and 31P NMR, Fourier transformRaman [
(Pd-Pt) = 138 cm-1], and UV-vis spectroscopy [
max(d
-d*) = 366 nm]. In a similar manner, [ClPd(-dppm)2Pt(1-dppm=O)][BF4] (2b), ligated with a dangling phosphine oxide, has been prepared by the addition ofdppm=O. The molecular structure of 2b has been established by an X-ray diffraction study. 2a reacts with 1 equivof NaBH4 to form the platinum hydride complex [(1-dppm)Pd(-dppm)2Pt(H)][BF4] (3). Both 2a and 3 react withan excess of NaBH4 to provide the mixed-metal d10-d10 compound [Pd(-dppm)3Pt] (4). The photophysical propertiesof 4 were studied by UV-vis spectroscopy [max(d-d*) = 460 nm] and luminescence spectroscopy (emi = 724nm; 
e = 12 ± 1 s, 77 K). The protonation of 1 and 4 leads to [ClPd(-dppm)2(-H)PtCl]+ (5) and 3, respectively.Stoichiometric treatment of 1 with cyclohexyl or xylyl isocyanide yields [ClPd(-dppm)2Pt(CNC6H11)]Cl (6a) and[ClPd(-dppm)2Pt(CN-xylyl)]Cl (6b) ligated by terminal-bound CNR ligands. In contrast, treatment of 1 with thephosphonium salt [C
NCH2PPh3]Cl affords the structurally characterized A-frame compound [ClPd(-dppm)2(-C=NCH2PPh3)PtCl]Cl (6c), spanned by a bridging isocyanide ligand. The electrochemical reduction of 2a at -1.2V vs SCE, as well as the reduction of 5 in the presence of dppm, leads to a mixture of products 3 and 4. Furtherreduction of 3 at -1.7 V vs SCE generates 4 quantitatively. The reoxidation at 0 V of 4 in the presence of Cl- ionsproduces back complex 2a. The whole mechanism of the reduction of 1 has been established.
-dppm)2Pt(1-dppm)][BF4] (2a),which contains a Pt-bound dangling dppm ligand. 2a has been characterized by 1H and 31P NMR, Fourier transformRaman [(Pd-Pt) = 138 cm-1], and UV-vis spectroscopy [max(d-d*) = 366 nm]. In a similar manner, [ClPd(-dppm)2Pt(1-dppm=O)][BF4] (2b), ligated with a dangling phosphine oxide, has been prepared by the addition ofdppm=O. The molecular structure of 2b has been established by an X-ray diffraction study. 2a reacts with 1 equivof NaBH4 to form the platinum hydride complex [(1-dppm)Pd(-dppm)2Pt(H)][BF4] (3). Both 2a and 3 react withan excess of NaBH4 to provide the mixed-metal d10-d10 compound [Pd(-dppm)3Pt] (4). The photophysical propertiesof 4 were studied by UV-vis spectroscopy [max(d-d*) = 460 nm] and luminescence spectroscopy (emi = 724nm; e = 12 ± 1 s, 77 K). The protonation of 1 and 4 leads to [ClPd(-dppm)2(-H)PtCl]+ (5) and 3, respectively.Stoichiometric treatment of 1 with cyclohexyl or xylyl isocyanide yields [ClPd(-dppm)2Pt(CNC6H11)]Cl (6a) and[ClPd(-dppm)2Pt(CN-xylyl)]Cl (6b) ligated by terminal-bound CNR ligands. In contrast, treatment of 1 with thephosphonium salt [CNCH2PPh3]Cl affords the structurally characterized A-frame compound [ClPd(-dppm)2(-C=NCH2PPh3)PtCl]Cl (6c), spanned by a bridging isocyanide ligand. The electrochemical reduction of 2a at -1.2V vs SCE, as well as the reduction of 5 in the presence of dppm, leads to a mixture of products 3 and 4. Furtherreduction of 3 at -1.7 V vs SCE generates 4 quantitatively. The reoxidation at 0 V of 4 in the presence of Cl- ionsproduces back complex 2a. The whole mechanism of the reduction of 1 has been established.