Phenyl tris(3-tert-butylpyrazolyl)borato complexes of lithium and thallium, [PhTpBut]M (M = Li, Tl): a novel structure for a monomeric tris(pyrazolyl)boratothallium complex and a study of its stereochemical nonrigidity by 1H and 205Tl NMR spectroscopy
Phenyl tris(3-tert-butylpyrazolyl)borato complexes of lithium and thallium, [PhTpBut]M (M = Li, Tl): a novel structure for a monomeric tris(pyrazolyl)boratothallium complex and a study of its stereochemical nonrigidity by 1H and 205Tl NMR spectroscopy
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锂和铊的苯基三(3-叔丁基吡唑基)硼酸配合物，[PhTpBut]M (M = Li, Tl)：单体三(吡唑基)硼酸铊配合物的新颖结构及其立体化学非刚性的研究 1H 和
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
G. Parkin
中科院分区：
文献类型：
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作者：
J. Kisko;T. Hascall;C. Kimblin;G. Parkin
报道了苯基取代三（3-叔丁基吡唑）硼酸配合物[PhTpBut]M（M = Li，Tl，H）的合成和结构。与其他单体[TpRR′]Tl衍生物（其显示三（吡唑基）硼酸酯配体的对称三齿配位）相比，[PhTpBut]Tl显示前所未有的结构。具体地，叔丁基吡唑基基团之一旋转约20 °。90°，T1通过吡唑基核的芳香族π-系统的p-轨道组分与直接连接到硼上的氮相互作用。[PhTpBut]Tl在室温下在溶液中在NMR光谱时间尺度上是立体化学非刚性的，但冷却至约100 ° C。-80 °C减慢动态过程，足以允许鉴定“轴向”和“赤道”异构体，其中描述符表示吡唑基相对于六元[BN 4 Tl]环的船形构型的位置。
The syntheses and structures of the phenyl substituted tris(3-tert-butylpyrazolyl)borato complexes, [PhTpBut]M (M = Li, Tl, H), are reported. In contrast to other monomeric [TpRR′]Tl derivatives, which exhibit symmetric tridentate coordination of the tris(pyrazolyl)borate ligand, [PhTpBut]Tl exhibits an unprecedented structure. Specifically, one of the tert-butylpyrazolyl groups is rotated by ca. 90° and the Tl interacts with the nitrogen attached directly to the boron via a p-orbital component of the aromatic π-system of the pyrazolyl nucleus. [PhTpBut]Tl is stereochemically nonrigid on the NMR spectroscopic timescale in solution at room temperature, but cooling to ca. –80 °C slows down the dynamic processes sufficiently to allow “axial” and “equatorial” isomers to be identified, with the descriptors denoting the position of the pyrazolyl group relative to the boat configuration of the six-membered [BN4Tl] ring.