Enciso Alan E, Lorandi Francesca, Mehmood Arshad, Fantin Marco, Szczepaniak Grzegorz, Janesko Benjamin G, Matyjaszewski Krzysztof
Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA.
Department of Chemistry and Biochemistry, Texas Christian University, 2800 South University Drive, Fort Worth, TX, 76129, USA.
Angew Chem Int Ed Engl. 2020 Aug 24;59(35):14910-14920. doi: 10.1002/anie.202004724. Epub 2020 Jun 17.
A facile and efficient two-step synthesis of p-substituted tris(2-pyridylmethyl)amine (TPMA) ligands to form Cu complexes with the highest activity to date in atom transfer radical polymerization (ATRP) is presented. In the divergent synthesis, p-Cl substituents in tris(4-chloro-2-pyridylmethyl)amine (TPMA ) were replaced in one step and high yield by electron-donating cyclic amines (pyrrolidine (TPMA ), piperidine (TPMA ), and morpholine (TPMA )) by nucleophilic aromatic substitution. The [Cu (TPMA )Br] complexes exhibited larger energy gaps between frontier molecular orbitals and >0.2 V more negative reduction potentials than [Cu (TPMA)Br] , indicating >3 orders of magnitude higher ATRP activity. [Cu (TPMA )] exhibited the highest reported activity for Br-capped acrylate chain ends in DMF, and moderate activity toward C-F bonds at room temperature. ATRP of n-butyl acrylate using only 10-25 part per million loadings of [Cu (TPMA )Br] exhibited excellent control.
本文提出了一种简便高效的两步法合成对取代三（2 - 吡啶甲基）胺（TPMA）配体的方法，该配体可形成在原子转移自由基聚合（ATRP）中具有迄今为止最高活性的铜配合物。在发散合成中，三（4 - 氯 - 2 - 吡啶甲基）胺（TPMA）中的对氯取代基通过亲核芳香取代一步被供电子环状胺（吡咯烷（TPMA）、哌啶（TPMA）和吗啉（TPMA））高产率地取代。[Cu(TPMA)Br]配合物在前沿分子轨道之间表现出更大的能隙，且还原电位比[Cu(TPMA)Br]负>0.2 V，表明其ATRP活性高>3个数量级。[Cu(TPMA)]对DMF中溴封端的丙烯酸酯链端表现出报道的最高活性，并且在室温下对碳 - 氟键具有中等活性。仅使用百万分之10 - 25负载量的[Cu(TPMA)Br]进行丙烯酸正丁酯的ATRP表现出优异的可控性。
