Catalytic performance of tridentate versus bidentate Co(ii) complexes supported by Schiff base ligands in vinyl addition polymerization of norbornene

• Published in: RSC advances Vol. 12; no. 55; pp. 35896 - 35904
• Main Authors: Kim, Kyeonghun, Nayab, Saira, Cho, Yerim, Jung, Hyewon, Yeo, Hyeonuk, Lee, Hyosun, Lee, Sang-Ho
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 12.12.2022; The Royal Society of Chemistry
• Subjects: Addition polymerization; Chemistry; Diamines; Ethane; Imines; Ligands; Molecular weight distribution; Polynorbornene; Steric hindrance
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d2ra07241f

A series of Co(ii) complexes supported by Schiff base ligands, L -L , where L , L , and L are ( )-3-methoxy- -(quinolin-2-ylmethylene)propan-1-amine, ( )- , -dimethyl- -(pyridin-2-ylmethylene)ethane-1,2-diamine, and ( )- , -dimethyl- -(thiophen-2-ylmethylene)ethane-1,2-diamine, respectively, were designed and synthesized. Structural studies revealed a distorted trigonal bipyramidal geometry for [L CoCl ] and a distorted tetrahedral geometry for [L CoCl ]. After activation with modified methyl aluminoxane (MMAO), all the Co(ii) complexes catalyzed the polymerization of norbornene (NB) to yield vinyl-type polynorbornenes (PNBs) with activities of up to 4.69 × 10 g mol Co h at 25 °C. High-molecular-weight ( of up to 1.71 × 10 g mol ) soluble PNBs with moderate molecular-weight distributions (MWD) were obtained. The activity of the Co(ii)/MMAO catalytic system is influenced by the steric hindrance and electronic properties of the ligands.