Configurational Flexibility of a Triaryl-Supported SBS Ligand with Rh and Ir: Structural Investigations and Olefin Isomerization Catalysis
Configurational Flexibility of a Triaryl-Supported SBS Ligand with Rh and Ir: Structural Investigations and Olefin Isomerization Catalysis
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DOI：
10.1021/acs.organomet.2c00121
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发表时间：
2022-05
期刊：
影响因子：
2.8
通讯作者：
Kyle D Spielvogel;G. Durgaprasad;Scott R. Daly
中科院分区：
文献类型：
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作者：
Kyle D Spielvogel;G. Durgaprasad;Scott R. Daly
在这里，我们报告了含有三芳基SBS钳形配体的Rh和Ir配合物，其两侧是中性硫甲基给体基团。重氮硼配体H(MeSBSMe)中的B-H键与[Ir(CoE)Cl]2或[Rh(Coe)Cl]2氧化加成得到氯桥二聚体[(MeSBSMe)MH(μ-Cl)]2，其中M=Ir(1)或Rh(2)。将CO加到1和2上得到了难以分离的不稳定产物，但从与1反应中恢复的单体(MeSBSMe)IRH(CO)Cl(3)的晶体表明，MeSBSMe的配位方式发生了变化。用LiN(SiMe_3)_2缩合二聚体-(MeSBSMe)IRH[N(SiMe_3)_2](4)和反常的RHI-RhIII二聚体(MeSBSMe)Rh(μ-H)[(MeS(μ-B)(μ-SMe)]Rh[N(SiMe3)2](5)与MeSm_3和Me_SBSm_4和5反应时，对叔丁烯和环辛烷没有表现出任何烷烃转移加氢反应活性，但它们对烯烃与1-己烯的异构化反应具有很高的活性。优化后的异构化反应在60℃下反应16h后的转化率(TON)最高，为4(TON=10 000)，两种催化剂在室温下的转化率相近(TON=600)。总而言之，这些数据突显了MeSBSM配体的反应性和固有的配位灵活性，以便与更成熟的PBP络合物进行比较。
Here, we report Rh and Ir complexes containing a triaryl SBS pincer ligand flanked by neutral thiomethyl donor groups. Oxidative addition of the B–H bond in the diazaborole proligand H(MeSBSMe) to [Ir(COD)Cl]2or [Rh(COE)Cl]2yielded the chloride-bridged dimers [(MeSBSMe)MH(μ-Cl)]2, where M = Ir (1) or Rh (2). Addition of CO to1and2yielded unstable products that were difficult to isolate, but crystals of monomeric (MeSBSMe)IrH(CO)Cl (3) recovered from the reactions with1revealed a change in theMeSBSMecoordination mode frommertofac. Treating1and2with LiN(SiMe3)2yieldedmer-(MeSBSMe)IrH[N(SiMe3)2] (4) and the unusual RhI–RhIIIdimer (MeSBSMe)Rh(μ-H)[(MeS(μ-B)(μ-SMe)]Rh[N(SiMe3)2] (5) with bothmerandfacMeSBSMe.4and5did not exhibit any alkane transfer hydrogenation reactivity when tested withtert-butylethylene and cyclooctane, but they are highly active for alkene isomerization with 1-hexene. Optimized isomerization reactions showed the highest turnover number (TON) with4at 60 °C after 16 h (TON = 10 000), and both catalysts are effective even when tested at room temperature with similar loadings (TON = 600). Collectively, these data highlight the reactivity and inherent coordinative flexibility of theMeSBSMeligand for comparison to more well-established PBP complexes.