Kreyenschmidt Friedrich, Eisele Niklas F, Hevelke Valentin, Rahrt Rene, Kreyenschmidt Anne-Kathrin, Koszinowski Konrad
Institut für Organische und Biomolekulare Chemie, Universität Göttingen, Tammannstraße 2, 37077, Göttingen, Germany.
Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, 37077, Göttingen, Germany.
Angew Chem Int Ed Engl. 2022 Oct 24;61(43):e202210211. doi: 10.1002/anie.202210211. Epub 2022 Sep 26.
Anionic coordination polymerizations proceed via highly reactive intermediates, whose in situ analysis has remained difficult. Here, we show that electrospray-ionization mass spectrometry is a promising method to obtain detailed information on the polymerization process. Focusing on polymerization reactions of 1,3-dienes initiated by CoCl /RLi (R=Me, nBu, tBu, Ph), we directly observe the growing polymer chains and characterize the active anionic cobalt centers by gas-phase fragmentation experiments. On the basis of these results, we suggest a plausible mechanism for the polymerization reaction. Moreover, the ESI mass spectra permit the determination of molecular weight distributions, which are in good agreement with those derived from NMR-spectroscopic as well as MALDI mass-spectrometric measurements, and afford a wealth of kinetic data.
阴离子配位聚合通过高活性中间体进行，对其进行原位分析一直很困难。在此，我们表明电喷雾电离质谱是一种有望获得聚合过程详细信息的方法。聚焦于由CoCl /RLi（R = 甲基、正丁基、叔丁基、苯基）引发的1,3 - 二烯的聚合反应，我们直接观察到增长的聚合物链，并通过气相裂解实验对活性阴离子钴中心进行表征。基于这些结果，我们提出了一种合理的聚合反应机理。此外，电喷雾电离质谱允许测定分子量分布，其与通过核磁共振光谱以及基质辅助激光解吸电离质谱测量得到的结果高度吻合，并提供了丰富的动力学数据。
