| Autor: |
Ren, Kaipai, Wen, Xin, Jiang, Yanfeng, Kang, Xiaohui, Luo, Yi |
| Předmět: |
|
| Zdroj: |
New Journal of Chemistry; 9/28/2024, Vol. 48 Issue 36, p16080-16087, 8p |
| Abstrakt: |
This theoretical study reveals the origin of regioselectivity of a polar vinyl monomer (PVM) in the copolymerization of different PVMs with ethylene by the DBB–Ipty α-diimine Pd(II) complex with a bulky dibenzobarrelene (DBB) backbone and bulky axial pentiptycenyl (Ipty) substituents. DFT calculations were employed to investigate the regioselectivity of the insertion of three acrylate monomers (CH2＝CHCOOR: R = H, AA; R = Me, MA; and R = tBu, tBA) catalyzed by the DBB–Ipty Pd(II) complex. The results indicate that with the increase of the size of the monomer substituents (AA < MA < tBA), greater repulsion occurs between the monomer and the catalyst, leading to a gradual preference for 1,2-insertion. By stepwise regression analysis, a multivariate linear regression (MLR) model on the factors affecting regioselectivity was constructed. Coefficient analysis of the MLR equation reveals that the buried volume (%Vbur) of the monomer and the NBO charge on the vinyl C1 atom (NBOC1) significantly affect the regioselectivity of monomer insertion. Specifically, the bigger %Vbur tends to 1,2-insertion of the PVM, while the higher NBOC1 is apt to 2,1-insertion. Through the contribution values of the coefficients in the equation, we can derive that steric hindrance is the primary factor of regioselectivity, while the electronic effect plays a secondary role. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
