Searching for Precursors to Metal-Metal Bonded Dipalladium Species: A Study of Pd24+ Complexes

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• 作者：John F. Berry ; F. Albert Cotton ; Sergey A. Ibragimov ; Carlos A. Murillo ; and Xiaoping Wang
• 刊名：Inorganic Chemistry
• 出版年：2005
• 出版时间：August 22, 2005
• 年：2005
• 卷：44
• 期：17
• 页码：6129 - 6137
• 全文大小：239K
• 年卷期：v.44,no.17(August 22, 2005)
• ISSN：1520-510X

文摘

Reactions of Pd₃(OAc)₆ with lithium salts of mononegative bidentate N,N-ligands, L, of various types, such asformamidinates, benzamidinates, triazinates, and guanidinates, were investigated in a search for ways to obtainPd₂⁴⁺ compounds that could serve as precursors to paddlewheel complexes with a metal-metal bond and a Pd₂⁵⁺core. It was found that the reactions are complex and that either square planar mononuclear or dinuclear speciesmay be formed depending on the reaction conditions or the method of isolation. For Pd₂L₄ compounds, ges/gifchars/alpha.gif" BORDER=0> and ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle">isomers were sometimes obtainable. In the ges/gifchars/alpha.gif" BORDER=0> isomer, all N,N-ligands serve as bridges, whereas in the ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> isomer,two ligands bridge the Pd₂⁴⁺ unit and each of the other two chelate to a metal atom. Electrochemistry shows thatthe paddlewheel compounds Pd₂(TolNC(H)NTol)₄, Pd₂(PhNC(Ph)NPh)₄, and Pd₂(PhNC(Ph)NPh)₃(OAc) and theorthometalated complex cis-Pd₂[ges/gifchars/eta.gif" BORDER=0 >²-C₆H₄NC(Ph)N(H)Ph]₂(ges/entities/mgr.gif">-OAc)₂ have reversible oxidation waves between 0.70and 0.92 V vs Ag/AgCl, which makes them good candidates for chemical oxidation.