Air and Thermally Stable Cyclic (Alkyl)(amino)carbene Ruthenium Complexes for Efficient Ring Expansion Metathesis Polymerization

• DOI: 10.1021/jacs.4c14219
• Publication Date: 2025-01-08T18:47:06Z
• Authors: Minjae Jang; Eunsong Jung; Yongkang Yang; Jinkyung Noh; Hayoung Song; Hyunseok Kim; Hoonseok Kang; Solhye Choe; Tae-Lim Choi; Eunsung Lee
• Keywords: Diene; Norbornene; Rational design

Ring expansion metathesis polymerization (REMP) has emerged as a potent strategy for obtaining cyclic polymers over the past two decades. The scope of monomers, however, remains limited due to poor functional group tolerance and stability catalyst, necessitating rational catalyst design address this constraint. Here, we present ruthenium complexes featuring tethered (alkyl)(amino)carbene ligands REMP, aiming deepen our understanding structure–property relationship in newly designed catalysts. Notably, these catalysts exhibit remarkable thermal even air, confirmed through monitoring air-exposed solution at 80 °C. In addition, initiation rate was effectively modulated by tuning steric hindrance N-aryl substituent, adjusting chain lengths, or introducing Blechert-type ligand. Based on systematic studies catalysts, successfully demonstrate challenging REMP allene (2,8-dimethylnona-4,5-diene) first time, well methyl-5-norbornene-2-carboxylate, resulting polymers. We also note that exceptional enables under air. This study provides valuable insights into introduces novel, user-friendly platform synthesis