Department of Chemistry, Chungbuk National University, 52 Naesudong-ro, Heungdeok-gu, Cheongju, Chungbuk 361-763, Republic of Korea.
Dalton Trans. 2012 Oct 14;41(38):11619-26. doi: 10.1039/c2dt31357j. Epub 2012 Aug 21.
The synthesis and characterization of LTi(O-i-Pr)(2) (1) and LTiCl(2) (2) complexes containing a new [ONNO]-type tetradentate diamine-diethanolate ligand such as (HOCMe(2)CH(2)NMeCH(2)CH(2)NMeCH(2)CMe(2)OH) (LH(2)) was achieved. Single-crystal X-ray analyses revealed that monomeric complexes 1 and 2 had pseudo-C(2) and pseudo-C(1) symmetric distorted octahedral geometry, respectively. Interestingly, complex 1 has fac-fac geometry for tetradentate L around a Ti centre in both solid and solution, whereas complex 2 has different geometry in solid (mer-fac, C(1)) and solution (fac-fac, C(2)). They are effective catalysts for the controlled ring opening polymerization of L-lactide, as shown by the linearity of the number average of the molecular weight of polylactides versus conversion, as well as narrow PDI values.
合成并表征了含有新型[ONNO]型四齿二胺二乙醇配体（如（HOCMe2CH2NMeCH2CH2NMeCH2CMe2OH）（LH2）的 LT i（O-i-Pr）2（1）和 LT iCl2（2）配合物。单晶 X 射线分析表明，单核配合物 1 和 2 分别具有拟 C2和拟 C1对称的扭曲八面体几何构型。有趣的是，配合物 1 在固体和溶液中，配体 L 围绕 Ti 中心具有 fac-fac 几何构型，而配合物 2 在固体（mer-fac，C1）和溶液（fac-fac，C2）中具有不同的几何构型。它们是 L-丙交酯可控开环聚合的有效催化剂，这表现为聚丙交酯的数均分子量与转化率呈线性关系，以及较窄的 PD I 值。
