Reactivity of the Iridium(I) Alkene/Alkyne Complex TpMe2Ir(C2H4)(MeO2CCCCO2Me)

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• 作者：Margarita Paneque ; Cristina M. Posadas ; Manuel L. Poveda ; Nuria Rend&oacute ; n ; Kurt Mereiter
• 刊名：Organometallics
• 出版年：2007
• 出版时间：June 18, 2007
• 年：2007
• 卷：26
• 期：13
• 页码：3120 - 3129
• 全文大小：235K
• 年卷期：v.26,no.13(June 18, 2007)
• ISSN：1520-6041

文摘

Tp^Me2Ir(C₂H₄)₂ (1; Tp^Me2 = hydrotris(3,5-dimethylpyrazolyl)borate) reacts with 1 equiv ofMeO₂CCCCO₂Me (DMAD) at 25 C, via the intermediacy of the known Ir(I) adductTp^Me2Ir(C₂H₄)(DMAD) (2), with formation of the bis(alkenyl) derivative Tp^Me2Ir(cis-C(R)=C(R)H)(CH=CH₂)(C₂H₄) (3; R = CO₂Me) in ca. 50% yield. Complex 3 slowly evolves to another alkenyl species,Tp^Me2Ir(cis-C(R)=C(R)H)(CH₂CH₂CH=CH₂) (4), which exists as a mixture of two stereoisomers.Interestingly, complex 2 reacts with the hard Lewis base NCMe at -20 C, giving the Ir(I) adduct Tp^Me2Ir(DMAD)(NCMe) (5) the first Ir(I) compound of the Tp^Me2Ir system with a hard ligand. The Ir-NCMebond in 5 is labile, and the acetonitrile is easily interchanged by CO, C₂H₄, and the alkynes HCCCO₂Me (MP) and DMAD. While with CO the reaction stops at the substitution stage with formation ofTp^Me2Ir(DMAD)(CO) (8), with C₂H₄ it gives complex 4 or the bis(alkenyl) species Tp^Me2Ir(cis-C(R)=C(R)H)(CH=CH₂)(NCMe) (9), depending on the concentration of NCMe in the reaction medium.With MP the known iridacyclopentadiene Tp^Me2Ir(C(R)=C(H)C(R)=C(R))(NCMe) (10) and thesymmetrical iridacycloheptatriene Tp^Me2Ir(C(R)=C(H)C(R)=C(R)C(H)=C(R)(NCMe) (11) can beobtained, while related iridacycles are formed with DMAD. Finally an iridapyrrole with the compositionTp^Me2Ir(Cl)(C(R)=C(R)C(Me)=NH) (6) is the unexpected result of heating complex 5 in a CH₂Cl₂-NCMe mixture at 120 C. All of the new compounds reported have been characterized by microanalysisand IR and NMR spectroscopy and, in addition, complexes 4 and 6 have been characterized by single-crystal X-ray studies.