conjugated 1,3-diene ligand such as o-xylylene, anthracene, and cyclooctatetraene have been synthesized and characterized. The molecular structures of Cp*Nbo-(CH2)2C6H4}Cl2 (1) (Cp*=η5-pentamethylcyclopentadienyl), Cp*Ta(η4-C14H10)(CH2Ph)2 (14), and Cp*Nb(η4-C4H6)(η3-C8H8) (16) were determined by X-ray crystallographic studies. Complexes 1 and 14 adopted a four-legged piano stool geometry and their o-xylylene
已合成并表征了具有扩展的共轭1,3-二烯
配体(例如
邻二甲苯,
蒽和环
辛酸酯)的
铌和
钽的半三明治复合物。的CP * Nb的分子结构 ø - (CH 2)2 C ^ 6 ħ 4 }
氯2(1)(CP * = η 5 -五甲基)中,CP * TA(η 4 -C 14 ħ 10)(CH 2 PH)2(14),1和CP *的Nb(η 4 -C 4 H ^ 6)(η 3 -C 8 ħ 8)(16)由X-射线晶体学研究测定。络合物1和14采用了四条腿的钢琴凳几何形状和其ö -xylylene和
蒽配体配位在
金属中心η 4 -coordination模式。X射线分析与他们的NMR谱数据一起显示,该ø -xylylene复杂1具有2的大的贡献σ -1 π规范形式,但在其他的
蒽络合物具有的2的增加的贡献π - η 4-二烯正则形式与
丁二烯配合物相比。因此,电子结构η 4 - ö -xylylene和η 4 -
蒽配体是从的偏离η