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Magnesium and calcium complexes bearing mono-oxidized or monoprotonated acenaphthylenebisamido ligand: Structure features and ROP activity
Journal of Organometallic Chemistry ( IF 2.1 ) Pub Date : 2020-09-16 , DOI: 10.1016/j.jorganchem.2020.121535
Alexander G. Morozov , Mikhail V. Moskalev , Danila A. Razborov , Igor L. Fedushkin

Acenaphthylenebisamido metal complexes (dpp-bian)Mg(thf)3 and (dpp-bian)Ca(thf)4 by reaction with azobenzene and dicumyl peroxide, respectively, give paramagnetic species [(dpp-bian)Mg(thf)NPh]2 (3) and (dpp-bian)CaOCMe2Ph(dme) (4) containing monoanionic dpp-bian ligand. Treating the parent compounds with 1 equiv of 2,6-di-tert-butyl-4-methylphenol leads to formation of amino/amidoacenaphthylene-supported complexes (dpp-bianH)MgO(tBu2MeC6H2)(thf) (5) and (dpp-bianH)CaO(tBu2MeC6H2)(thf)2 (6) featuring ancillary bulky phenoxido ligand. As NMR studies confirm, a sterically demanding moiety in the magnesium coordination sphere hinders the intramolecular shuttle proton transfer in 5, whereas calcium complex 6 maintains typical dynamics in solution. Compounds obtained show a modest activity in ROP of L-lactide in toluene. In particular, 3 and 4 prove to be active for moderate-controlled polymerization, whereas 5 and 6 give broadly dispersed PLAs.



中文翻译:

带有单氧化或单质子化ena双联酰胺配体的镁和钙配合物:结构特征和ROP活性

通过分别与偶氮苯和过氧化二枯基反应,亚甲基双酰胺金属配合物(dpp-bian)Mg(thf)3和(dpp-bian)Ca(thf)4产生顺磁性物质[(dpp-bian)Mg(thf)NPh] 23)和包含单阴离子dpp-bian配体的(dpp-bian)CaOCMe 2 Ph(dme)(4)。用1当量的2,6-二叔丁基-4-甲基苯酚处理母体化合物会形成氨基/ ami并ena撑的配合物(dpp-bianH)MgO(t Bu 2 MeC 6 H 2)(thf)(5)和(dpp-bianH)CaO(t Bu 2 MeC 6 H2)(thf)26)的特征是辅助的庞大的苯氧基配体。正如NMR研究所证实的,镁配位球中的空间需求部分阻碍了分子内穿梭质子在5中的转移而钙络合物6在溶液中保持了典型的动力学。获得的化合物在甲苯中的L-丙交酯的ROP中显示适度的活性。特别是,34被证明对中度控制的聚合反应有活性,而56则可得到广泛分散的PLA。

更新日期:2020-09-24
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