Syntheses and Structures of Tris‐β‐Diketiminate Lanthanide Complexes and Their High Activity for Ring‐Opening Polymerization of ϵ‐Caprolactone and L‐Lactide
Syntheses and Structures of Tris‐β‐Diketiminate Lanthanide Complexes and Their High Activity for Ring‐Opening Polymerization of ϵ‐Caprolactone and L‐Lactide
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DOI：
10.1002/ejic.200900313
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发表时间：
2009-09
影响因子：
2.3
通讯作者：
Mingqiang Xue;Rui Jiao;Yong Zhang;Yingming Yao;Q. Shen
中科院分区：
文献类型：
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作者：
Mingqiang Xue;Rui Jiao;Yong Zhang;Yingming Yao;Q. Shen
{[(4-XC6H4)NC(Me)]2CH}Li与无水镧系三氯化物（LnCl3）以3:1的摩尔比复合得到一系列三β二氯酸配合物，其通式为[LnLX3] [X = Cl, LCl: Ln = Pr (1), Nd (2), Sm (3)]；X = H, L: Ln = Nd (4)；X = Me, LMe: Ln = Nd(5)]。β-二氯胺酸钠盐与无水LnCl3在thf中以1:1的摩尔比反应得到相应的β-二氯胺酸镧系化合物[LClPrCl2(thf)2](6)、[LMeNdCl2(thf)2](7)和[LNdCl2(thf)2] {L = [(2,6- ipr2c6h3)NC(Me)]2CH -}(8)。对配合物进行了表征，并通过x射线单晶结构分析确定了配合物1-5和8的分子结构。在温和的条件下，配合物1-5对ϵ-caprolactone （ϵ-CL）和l -丙交酯（L-LA）的开环聚合具有非常活跃的单组分引发剂，聚合物具有较高的分子量和中等的多分散性，而配合物6-8在相同的聚合条件下没有表现出活性。三-β-二氯胺酸镧系配合物具有较高的催化活性，可能是由于中心金属周围密集的配位球导致Ln -β-二氯胺酸键活化。（©Wiley-VCH Verlag GmbH & Co. KGaA，德国Weinheim 69451, 2009）
Metathesis of {[(4–XC6H4)NC(Me)]2CH}Li with anhydrous lanthanide trichlorides (LnCl3) in a 3:1 molar ratio yielded a series of tris-β-diketiminate complexes with the general formula [LnLX3] [X = Cl, LCl: Ln = Pr (1), Nd (2), Sm (3); X = H, L: Ln = Nd (4); X = Me, LMe: Ln = Nd (5)]. Reaction of sodium salt of β-diketiminate with anhydrous LnCl3 in a 1:1 molar ratio in thf afforded the corresponding β-diketiminate lanthanide dichlorides [LClPrCl2(thf)2] (6), [LMeNdCl2(thf)2] (7), and [LNdCl2(thf)2] {L = [(2,6-iPr2C6H3)NC(Me)]2CH–} (8), respectively. Each of these complexes was characterized, and the molecular structures of complexes 1–5 and 8 were determined by X-ray single-crystal structure analysis. Complexes 1–5 were found to be very active single-component initiators for the ring-opening polymerization of ϵ-caprolactone (ϵ-CL) and L-lactide (L-LA) under mild conditions, giving polymers with high molecular weight and moderate polydispersities, whereas complexes 6–8 displayed no activity under the same polymerization conditions. The high catalytic activity shown by tris-β-diketiminate lanthanide complexes may be attributed to the activated Ln–β-diketiminate bond caused by the crowded coordination sphere around the central metal.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)