Department of Chemistry, Lomonosov Moscow State University, 1/3 Leninskie Gory, 119991 Moscow, Russia.
Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy.
J Am Chem Soc. 2021 May 26;143(20):7641-7647. doi: 10.1021/jacs.1c03380. Epub 2021 May 12.
Absolute rigidity is rare in the "soft" world of organometallics. Here we introduce two cyclopenta[]triptycyl -zirconocene catalysts for isotactic-selective propene polymerization, designed by means of an integrated high-throughput experimentation/quantitative structure-activity relationship modeling approach. An ultrarigid ligand precisely wrapped around the Zr center enforces an enzyme-like lock and key fit, effectively hampering undesired reactive events, even at high temperature. Stereodefective units are hardly detectable by C NMR in the polymer produced at 120 °C; this corresponds to an enantioselectivity exceeding 6-7 kcal/mol: i.e., less than 1 propene misinsertion every 4000 (and at room temperature, one every ∼40000!).
在“软”的金属有机世界中，绝对刚性很少见。在这里，我们通过集成高通量实验/定量结构-活性关系建模方法，介绍了两种用于等规选择性丙烯聚合的环戊[]苝基-锆络合物催化剂。超刚性配体精确地包裹在 Zr 中心周围，形成类似于酶的锁和钥匙配合，即使在高温下，也能有效地阻止不必要的反应发生。在 120°C 下聚合得到的聚合物中，通过 C NMR 几乎检测不到立体缺陷单元；这对应于超过 6-7 kcal/mol 的对映选择性：即在 4000 个（在室温下，每 40000 个！）丙烯中，插入错误的不到 1 个。
