respectively. The ligand disoppf also induces considerable distortion away from square-planar geometry in the complex [Rh(nbd)(disoppf)][BF4]4nbd = norbornadiene (bicyclo[2.2.1]hepta-2,5-diene)}, as found in a crystal structure determination, which may account for the unusual lability of the chelating diphosphine. This is demonstrated by its reactions with Ph2P(CH2)nPPh2(n= 1 or 2) both of which give
[Ir(cod)(L–L)] + 3 [cod =环辛基-1,5-二烯,L–L = 1-(
二异丙基膦基)-1'-(
二苯基膦基)
二茂铁]的晶体结构可能与L–L = 1,1'-双(
二苯基膦基)
二茂铁(dppf)1和1,1'-双(
二异丙基膦基)
二茂铁(disppf),2的类似络合物的那些,所有络合物都易于从[Ir (鳕鱼)(py)2 ] +(py =
吡啶)。通过改变
二茂铁的扭曲(随膦的立体分布的增加而减小)以及
铱原子上的几何形状从正方形平面向四面体变形,可以在所有三个配合物中维持最佳的
二膦咬合角约99°。
二茂铁部分的扭曲在所有三个配合物中诱导
铱原子上的手性,并且立体异构体的互换可以通过可变温度的1 H NMR光谱进行。在此过程中,使用Eyring方程得出的近似值ΔG ‡为36.1±0.2、39.3±0.2和34.3±0.2 kJ mol –1(对于1–3)分别。配位体disoppf还会在复合物[Rh(nbd)(disoppf)]