and three fluoro ligands. At elevated temperatures, stereoisomeric interconversion caused by hindered intramolecular rotation of the aph(-) ligand occurs. The mechanism of this process was elucidated on the basis of the dynamic effects in (19)F spectra and line-shape analysis of the trans-CH(3) resonance in (13)C spectra split due to direct "through-space" coupling with the proximate fluoro ligand.
使用(1)H,(13)C,(15)N和(19)F NMR光谱的一维和二维技术,证明了
丙酮苯zone(H-aph)作为两中心N [WOF(4)(aph)](-)中的N供体
配体。与
钨配位的结果是,
配体构象从E变为Z,同时苯环从> NN = C <平面翻转。在低温(-30摄氏度)下,五角-双锥体钨多面体的赤道面包含两个donor的供体氮原子和三个氟配体。在升高的温度下,发生由aph(-)
配体的分子内旋转受阻引起的立体异构体互变。