Metallacycloheptatrienes of Iridium(III): Synthesis and Reactivity

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• 作者：Margarita Paneque ; Cristina M. Posadas ; Manuel L. Poveda ; Nuria Rendó ; n ; Laura L. Santos ; Eleuterio Á ; lvarez ; Veró ; nica Salazar ; Kurt Mereiter ; Enrique O&ntilde ; ate
• 刊名：Organometallics
• 出版年：2007
• 出版时间：July 2, 2007
• 年：2007
• 卷：26
• 期：14
• 页码：3403 - 3415
• 全文大小：345K
• 年卷期：v.26,no.14(July 2, 2007)
• ISSN：1520-6041

文摘

The Ir(I)-butadiene complex Tp^Me2Ir(mages/gifchars/eta.gif" BORDER=0 >⁴-CH₂=C(Me)C(Me)=CH₂) (1) (Tp^Me2 = hydrotris(3,5-dimethylpyrazolyl)borate) reacts with mages/entities/ge.gif">3 equiv of DMAD (RCmages/entities/tbd1.gif">CR, R = CO₂Me) in CH₂Cl₂ at 60 mages/entities/deg.gif">C,in the presence of adventitious water, with formation of the iridacycloheptatriene m061036oa10001">Tp^Me2m061036o00000">Ir(C(R)=C(R)C(R)=C(R)C(R)=C(R))(H₂O) (2), by the oxidative coupling of three molecules of DMAD in the metalcoordination sphere. In a related process, Tp^Me2IrPh₂(N₂) (4) gives two benzoannelated iridacycloheptatrienes, the symmetrical species m061036oa10002">Tp^Me2m061036o00000">Ir(C(R)=C(R)-o-C₆H₄C(R)=C(R))(H₂O) (5) and the unsymmetricalone m061036oa10003">Tp^Me2m061036o00000">Ir(C(R)=C(R)C(R)=C(R)-o-C₆H₄)(H₂O) (6). The water ligand in these complexes is labile,and derivatives substituted with CO, PMe₃, and NCMe have been obtained. 2, 5, and 6 react, at 25 mages/entities/deg.gif">C,with oxo-transfer oxidizing reagents such as ^tBuOOH with formation of the keto-metallabicyclic products7-9, which result from the selective oxo attack to the mages/gifchars/gamma.gif" BORDER=0 >,mages/gifchars/delta.gif" BORDER=0 >-C=C double bond, irrespective of this beingof the benzo or the (R)C=C(R) type. In the latter case, further oxidation takes place with ^tBuOOH, atambient temperature, with formation of an iridabenzene (11) and an iridanaphthalene (12) (with five andthree electron-withdrawing CO₂Me substituents, respectively) in which the carboxylate MeO₂CCO₂^- ligandcompletes the metal coordination sphere. Interestingly, substitution of this group by OH^- or MeO^- allowsthe formation of Jackson-Meisenheimer complexes, reflecting the inherent aromaticity of these electron-deficient metalloaromatics. Finally, the hydrogenation of the iridacycloheptatrienes has been studied. Allnew compounds have been fully characterized by microanalysis, IR and NMR spectroscopies, and, insome cases, single-crystal X-ray diffraction studies.