New cyclopentadienylethylphosphane chelate complexes with unsymmetrical phosphane substitution
New cyclopentadienylethylphosphane chelate complexes with unsymmetrical phosphane substitution
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具有不对称膦取代的新型环戊二烯基乙基膦螯合物
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
H. Butenschön
中科院分区：
文献类型：
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作者：
K. Janssen;H. Butenschön
本文报道了磷原子上具有不对称取代的(膦乙基)环戊二烯基钴、铑、铱、镍和铬的配合物的合成、表征和一些反应。通过螺环[2.4]七-4，6-二烯与叔丁基苯基磷化锂或叔丁基环己基磷化锂的亲核开环反应制备了配体体系。阴离子配体通过金属卤化物试剂处理得到各自的络合物。在三种情况下，可以获得X射线晶体结构分析。钴配合物与二氢硅烷发生氧化加成反应，生成具有磷、钴和硅三个立体中心的产物，其动态行为如VT核磁共振所示。Rh(III)络合物与碘甲烷的氧化加成反应选择性地形成相应的Rh(III)络合物。虽然先前观察到由平面手性吲哚配体或螯合主链上的立体碳中心引起的非对映选择性，但这是第一个由立体磷配体引起的立体诱导。用真空核磁共振方法测定了钴和铑的转动活化能。
The syntheses, characterization, and some reactions of (phosphanylethyl)cyclopentadienyl chelate complexes of cobalt, rhodium, iridium, nickel, and chromium with unsymmetrical substitution at the phosphorus atom are described. The ligand systems were prepared by nucleophilic ring opening of spiro[2.4]hepta-4,6-diene with lithium tert-butylphenylphosphide or lithium tert-butylcyclohexylphosphide. The anionic ligands give the respective chelate complexes by treatment with metal halide reagents. In three cases it was possible to obtain X-ray crystal structure analyses. The cobalt chelate complex undergoes oxidative addition with a dihydrosilane, the reaction results in the formation of products with three stereogenic centers at phosphorus, cobalt, and silicon, which show dynamic behavior as indicated by VTNMR. The rhodium chelate complex undergoes oxidative addition of iodomethane with diastereoselective formation of the respective Rh(III) chelate. While diastereoselectivity caused by a planar chiral indenyl ligand or by a stereogenic carbon center in the chelate backbone has earlier been observed, this is the first case of a stereoinduction by the stereogenic phosphorus ligand. Activation energies for the rotation of cobalt and rhodium chelates have also been determined by VTNMR.