A steric control on the reductive capacity of ytterbocenes towards iminopyridine ligands is described. The reaction of (η5-C9H7)2Yb(THF)2 with a series of 6-organyl-2-(aldimino)pyridyl ligands (IPy) takes place with the replacement of two THF molecules by one IPy unit. In contrast to the rich reductive ytterbocene chemistry described in the presence of the unsubstituted (aldimino)pyridyl ligand, all 6-aryl substituted IPys scrutinized hereafter are involved into the metal coordination as neutral bidentate N,N} or tridentate N,N,S; N,N,O} ligands, with no changes of the metal oxidation state in the final complexes. A series of YbII metallocene complexes of general formula (η5-C9H7)2YbII(η2 or η3)[2,6-iPr2(C6H3)NCH(C5H3N)-6-R)] have been isolated and completely characterized. The stereo-electronic role of the aryl substituents in the IPy ligands on the ytterbocene redox chemistry has also been addressed.
                                    介绍了
镱对
亚胺吡啶配体还原能力的立体控制。(Î-5-
C9H7)2Yb(THF)2 与一系列 6-芳基-2-(醛亚
氨基)
吡啶配体 (IPy) 反应时,两个 THF 分子被一个 IPy 单元取代。与未取代的(醛亚
氨基)
吡啶配体存在时所描述的丰富的还原性
镱化学反应不同,本文研究的所有 6-芳基取代的 IPy 都是以中性双齿N,N}或三齿N,N,S; N,N,O}
配体的形式参与
金属配位,最终配合物中的
金属氧化态没有发生变化。一系列通式为(δ-5-    )2YbII(δ-2 或 δ-3)[2,6-iPr2(
C6H3)NCH(
C5H3N)-6-R)] 的 YbII 茂
金属配合物已被分离并完全表征。此外,还研究了 IPy 
配体中芳基取代基对二茂
镱氧化还原
化学反应的立体电子作用。