Competition between π Donation and α-C−H Agostic Interactions in Complexes of the Type Tp‘Ta(CH-t-Bu)(X)(Y) (X = Halide; Y = Halide, NR2, OR; Tp‘ = Hydrotris(3,5-dimethylpyrazolyl)borate)
Competition between π Donation and α-C−H Agostic Interactions in Complexes of the Type Tp‘Ta(CH-t-Bu)(X)(Y) (X = Halide; Y = Halide, NR2, OR; Tp‘ = Hydrotris(3,5-dimethylpyrazolyl)borate)
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TpTa(CH-t-Bu)(X)(Y) 型配合物中 π 供体和 α-C−H 不相互作用之间的竞争（X = 卤化物；Y = 卤化物，NR2，OR；Tp = Hydrotris (3,5-二甲基吡唑基)硼酸酯)
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
K. Abboud
中科院分区：
文献类型：
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作者：
J. Boncella;Mary L. Cajigal;K. Abboud
化合物 Tp‘Ta(CHC(CH3)3)X2 (2 (X = Cl), 3 (X = Br)) (Tp‘ = 加氢三(3,5-二甲基吡唑基)硼酸盐) 是通过 KTp‘ 与 Ta(CHC(CH3)3)X3(thf)2 在 THF 中反应合成的。 2中的一个Cl配体可以被OR-(R=i-Pr、Me)或NMe2-取代。由于金属中心和亚烷基质子之间的 α-H 相互作用，亚烷基碳的 1JC-H 值一致较低。这些化合物中 1JC-H 的大小取决于其余配体的 π 供体性质。尝试通过用 N(H)Ar- 取代 2 中的 Cl- 来合成单芳基酰胺络合物，导致质子从 N 转移到 C，并形成亚氨基络合物 Tp'Ta(CH2C(CH3)3)(NAr)Cl (Ar = 2,6-i-PrC6H3 (7), Ph (8))。当 2 与 KN(Me)Ph 反应时，质子从 Me 基团转移到亚烷基碳，得到亚胺络合物 Tp‘Ta(η2-CH2NPh)(CH2CMe3)Cl (9)。 9 的单晶 X 射线衍射研究证实了该结构，并表明 9 最好被描述为氮杂金属环......
The compounds Tp‘Ta(CHC(CH3)3)X2 (2 (X = Cl), 3 (X = Br)) (Tp‘ = hydrotris(3,5-dimethylpyrazolyl)borate), have been synthesized by the reaction of KTp‘ with Ta(CHC(CH3)3)X3(thf)2 in THF. One Cl ligand in 2 can be substituted with OR- (R = i-Pr, Me) or NMe2-. The values of 1JC-H for the alkylidene carbon are uniformly low due to the α-H agostic interaction between the metal center and the alkylidene proton. The magnitude of 1JC-H in these compounds depends upon the π donor properties of the remaining ligands. Attempted synthesis of monoarylamide complexes by displacement of Cl- from 2 with N(H)Ar- results in proton transfer from N to C and formation of the imido complexes Tp‘Ta(CH2C(CH3)3)(NAr)Cl (Ar = 2,6-i-PrC6H3 (7), Ph (8)). When 2 reacts with KN(Me)Ph, proton transfer occurs from the Me group to the alkylidene carbon giving the imine complex Tp‘Ta(η2-CH2NPh)(CH2CMe3)Cl (9). A single-crystal X-ray diffraction study of 9 confirmed the structure and suggested that 9 is best described as an azametallacycl...