Synthesis and Reactivity of New Complexes of Rhodium and Iridium with Bis(dichloroimidazolylidene) Ligands. Electronic and Catalytic Implications of the Introduction of the Chloro Substituents in the NHC Rings
Synthesis and Reactivity of New Complexes of Rhodium and Iridium with Bis(dichloroimidazolylidene) Ligands. Electronic and Catalytic Implications of the Introduction of the Chloro Substituents in the NHC Rings
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DOI：
10.1021/om060174a
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发表时间：
2006-05
期刊：
影响因子：
2.8
通讯作者：
Mónica Viciano;Elena Mas-Marzá;M. Sanaú;E. Peris
中科院分区：
文献类型：
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作者：
Mónica Viciano;Elena Mas-Marzá;M. Sanaú;E. Peris
合成了一种新的双（二氯咪唑亚基）配体，得到了Rh（I）和Ir（I）的螯合-N-杂环配合物，并对其进行了表征。三个新的配合物的晶体结构进行了描述。基于羰基衍生物的ν（CO）伸缩频率对新配体的电子性质进行了研究，结果表明，氯代咪唑亚基配体的σ-贡献明显小于相应的非氯代类似物.这种电子修饰的配体具有重要的影响，所获得的化合物的催化性能，从增强的活性所示的催化氢化硅烷化的末端乙炔和环化的炔羧酸，相比，与非氯化NHC类似物配体的配合物。
The preparation of a new bis(dichloroimidazolylidene) ligand has provided chelate-N-heterocyclic complexes of Rh(I) and Ir(I), which have been fully characterized. The crystal structures of three of the new complexes are described. The study of the electronic properties of the new ligands was made on the basis of the ν(CO) stretching frequencies of the carbonyl derivatives, showing that the chloroimidazolylidene ligand is significantly less σ-donating than the related nonchlorinated analogue. This electronic modification of the ligand has important implications for the catalytic properties of the compounds obtained, as observed from enhanced activity shown in catalytic hydrosilylation of terminal acetylenes and cyclization of acetylenic carboxylic acids, compared to the complexes with the nonchlorinated NHC analogue ligand.