Cohen Ad, Yeori Adi, Goldberg Israel, Kol Moshe
School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.
Inorg Chem. 2007 Oct 1;46(20):8114-6. doi: 10.1021/ic701370t. Epub 2007 Sep 8.
A straightforward synthesis of a new type of tetradentate dianionic [OSSO]-type ligand is described. This ligand features an ethylenedithiol core bridged via methylene groups to substituted phenols, thus representing an S analogue of the [ONNO]-type Salan ligands. The [OSSO]H2 ligand precursor reacted with titanium(IV) isopropoxide and with zirconium(IV) tert-butoxide to give the corresponding [OSSO]-M(OR)2 complexes, which formed as single C2-symmetric isomers but were fluxional according to variable-temperature NMR. An X-ray structure of [OSSO]-Zr(O-t-Bu)2 supported the fac-fac wrapping mode of the ligand. The dibenzyl complex [OSSO]-Zr(bn)2 that was obtained by a reaction between the ligand precursor and tetrabenzylzirconium was found to be an active 1-hexene polymerization catalyst upon activation with B(C6F5)3, leading to a stereoirregular polymer despite its C2 symmetry.
本文描述了一种新型四齿双阴离子[OSSO]型配体的直接合成方法。该配体具有一个乙二硫醇核心，通过亚甲基桥连到取代酚上，因此是[ONNO]型Salan配体的硫类似物。[OSSO]H2配体前体与异丙醇钛和叔丁醇锆反应，得到相应的[OSSO]-M(OR)2配合物，这些配合物以单一的C2对称异构体形式形成，但根据变温核磁共振显示具有动态变化。[OSSO]-Zr(O-t-Bu)2的X射线结构支持了配体的面-面包裹模式。通过配体前体与四苄基锆反应得到的二苄基配合物[OSSO]-Zr(bn)2，在用B(C6F5)3活化后被发现是一种活性的1-己烯聚合催化剂，尽管其具有C2对称性，但导致形成立体不规则聚合物。
