Catalytic performance of tridentate versus bidentate Co(ii) complexes supported by Schiff base ligands in vinyl addition polymerization of norbornene. Issue 55 (21st December 2022)

• Record Type: Journal Article
• Authors: Kim, Kyeonghun; Nayab, Saira; Cho, Yerim; Jung, Hyewon; Yeo, Hyeonuk; Lee, Hyosun; Lee, Sang-Ho
• Is Part Of: RSC advances. Volume 12:Issue 55(2022)
• Page Start: 35896
• Page End: 35904
• Publication Date: 2022-12-21
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d2ra07241f
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A series of Co(ii ) complexes supported by Schiff base ligands were designed and synthesized. A distorted tetrahedral geometry of [LC CoCl2 ] showed excellent catalytic activity at 25 °C (99% yield). Abstract : A series of Co(ii ) complexes supported by Schiff base ligands, LA –LC, where LA, LB, and LC are ( E )-3-methoxy- N -(quinolin-2-ylmethylene)propan-1-amine, ( E )- N 1, N 1 -dimethyl- N 2 -(pyridin-2-ylmethylene)ethane-1, 2-diamine, and ( E )- N 1, N 1 -dimethyl- N 2 -(thiophen-2-ylmethylene)ethane-1, 2-diamine, respectively, were designed and synthesized. Structural studies revealed a distorted trigonal bipyramidal geometry for [LB CoCl2 ] and a distorted tetrahedral geometry for [LC CoCl2 ] . 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 4 gPNB mol Co −1 h −1 at 25 °C. High-molecular-weight ( M n of up to 1.71 × 10 5 g mol −1 ) 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.