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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Synthesis, structure and oxidation of new ytterbium(II) bis(phenolate) compounds and their catalytic activity towards epsilon-caprolactone
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Synthesis, structure and oxidation of new ytterbium(II) bis(phenolate) compounds and their catalytic activity towards epsilon-caprolactone

机译：新的双（酚）（II）化合物的合成，结构和氧化及其对ε-己内酯的催化活性

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摘要

Two ytterbium(II) bis(phenolate) complexes, [(LYb)-Yb-R] where R = NMe2 1 and OMe 2, have been synthesized and characterized, with 1 being structurally defined to be a dimeric species with an unsymmetrical coordination of the bis(phenolate) ligand which is preserved in solution. Both 1 and 2 have been oxidized by a variety of oxidants (AgX, ROH) to form heteroleptic ytterbium(III) bis(phenolate) complexes: [(L-NMe2)YbPF6] (3), [(L-NMe2)YbOSO2CF3(thf)] (4), [(L-NMe2)YbOBut] (5), [(L-NMe2)YbOPh] (6), [(L-Ome)YbOPh] (7). Compound 4 has been structurally characterized as having a quasi-octahedral environment around ytterbium, with significant inter species hydrogen bonding between CHx and triflate fluorine atoms. Ligand exchange between Yb(N(SiMe3)(2))(3)(thf)(2) and H2LR yielded [(L-NMe2)YbN(SiMe3)(2)] (8) and [(L-OMe)YbN(SiMe3)(2)] (9), while metathesis from YbI2(thf)(2) and K2LOme reproducibly afforded the surprising oxidized product [(L-OMe)(2)YbK(dme)(2)] (10), which was structurally characterized as having a distorted octahedral environment around the ytterbium(III) centre. Compounds 1-9 were used to polymerize epsilon-caprolactone at room temperature in toluene, with only compounds 1, 2, 8 and 9 exhibiting significant catalytic activities. The polycaprolactone formed in these reactions was generally of high molecular weight and polydispersities <1.90 in all but one case.
机译：合成并表征了两种（II）双酚盐配合物[（LYb）-Yb-R]，其中R = NMe2 1和OMe 2，其中1在结构上定义为具有不对称配位的二聚体保留在溶液中的双酚盐配体。 1和2均已被多种氧化剂（AgX，ROH）氧化形成杂配的（（III）双酚盐配合物：[[L-NMe2）YbPF6]（3），[（L-NMe2）YbOSO2CF3（ thf）]（4），[（L-NMe2）YbOBut]（5），[（L-NMe2）YbOPh]（6），[（L-Ome）YbOPh]（7）。化合物4在结构上已被表征为在around周围具有准八面体环境，在CHx和三氟甲磺酸氟原子之间具有显着的种间氢键键合。 Yb（N（SiMe3）（2））（3）（thf）（2）与H2LR之间的配体交换产生[（L-NMe2）YbN（SiMe3）（2）]（8）和[（L-OMe）YbN （SiMe3）（2）]（9），同时从YbI2（thf）（2）和K2LOme复分解提供令人惊讶的氧化产物[（L-OMe）（2）YbK（dme）（2）]（10），其结构特征是在（（III）中心周围具有扭曲的八面体环境。化合物1-9用于在室温下于甲苯中聚合ε-己内酯，只有化合物1、2、8和9表现出显着的催化活性。在这些反应中形成的聚己内酯通常具有高分子量，除一种情况外，其他所有分散度均＜1.90。

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