Modifying Electronic Communication in Dimolybdenum Units by Linkage Isomers of Bridged Oxamidate Dianions

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• 作者：F. Albert Cotton ; Chun Y. Liu ; Carlos A. Murillo ; Dino Villagrá ; n ; and Xiaoping Wang
• 刊名：Journal of the American Chemical Society
• 出版年：2003
• 出版时间：November 5, 2003
• 年：2003
• 卷：125
• 期：44
• 页码：13564 - 13575
• 全文大小：380K
• 年卷期：v.125,no.44(November 5, 2003)
• ISSN：1520-5126

文摘

Reactions of Mo₂(O₂CCH₃)(DAniF)₃, DAniF = N,N'-di-p-anisylformamidinate, with oxamidatedianions [ArNC(O)C(O)NAr]^2-, Ar = C₆H₅ and p-anisyl, give pairs of isomeric compounds where the [Mo₂]units are bridged by the oxamidate anions. For the ges/gifchars/alpha.gif" BORDER=0> isomers, the C-C unit of the dianion is nearlyperpendicular to the Mo-Mo bonds, and these are essentially perpendicular to each other. For the ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> isomers,the corresponding C-C unit and the Mo-Mo bonds are essentially parallel to each other. Each type ofisomer is stable in solution. The electronic communication as measured by the ges/gifchars/Delta.gif" BORDER=0 >E_1/2 for the oxidation ofeach of the Mo₂ units is significantly better for the ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> isomers. This is supported also by the appearance ofwhat is conventionally called an intervalence charge-transfer band in the near infrared region upon oxidationof the ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> isomers but not the ges/gifchars/alpha.gif" BORDER=0> isomers. Molecular mechanics and DFT calculations help explain the relativeconformations in the ges/gifchars/alpha.gif" BORDER=0> isomers and the relative energy differences between the ges/gifchars/alpha.gif" BORDER=0> and ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> isomers.