Abstract
AbstractThe copolymerizations of (S)‐1,2‐propanediyl and (2S,3S)‐2,3‐butanediyl bis(4‐vinyl‐benzoate)s (2a and 2b) (M1) with styrene (M2) were carried out using 2,2′‐azoisobutyronitrile in toluene at 60 °C. For the cyclocopolymer 3, the extent of cyclization of 3b is higher than that of 3a. The monomer reactivity ratios are r1 = 8.34 and r2 = 0.27 for 2a and r1 = 6.82 and r2 = 0.19 for 2b. The specific rotation ([α] in deg · dm−1 · g−1 · cm3 c = 1.0 g · dL−1; CHCl3) changes from +230 to +176 for 3a and from +319 to +150 for 3b. After removing the chiral templates, the resulting poly[(methyl 4‐vinylbenzoate)‐co‐styrene]s showed a specific rotation ([α] in deg · dm−1 · g−1 · cm3 c = 1.0 g · dL−1; CHCl3) of −2 for 4a and of −8 for 4b, indicating that the (2S,3S)‐2,3‐butanediyl template shows a higher ability to cause asymmetric induction by comparison with the (S)‐1,2‐propanediyl one. A split Cotton effect due to the positive chirality was observed in the CD spectrum of 2 and the reversed one for 4. According to the CD exciton chirality method, the clockwise‐twist of two 4‐vinylbenzoate for 2 transmitted its chirality to 4 in which two 4‐vinylbenzoyl groups are twisted counterclockwise, i. e., an (R,R)‐configuration of vicinal (methyl 4‐vinylbenzoate) units in the main chain.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.