Synthesis and helical structure of poly(1-methylpropargyl ester)s with various side chains.
Optically active 1-methylpropargyl esters bearing various substituents were polymerized with [(nbd)Rh](+)[eta(6)-C(6)H(5)B(C(6)H(5))(3)](-) (nbd=norbornadiene) as a catalyst to afford the corresponding poly(1-methylpropargyl ester)s with moderate molecular weights in good yields. The polymers have a cis-stereoregular structure, which was determined by (1)H NMR spectroscopy. Large optical rotations and clear CD signals demonstrated that all these polymers take on a helical structure with a predominantly one-handed screw sense. The polymers exhibited large viscosity indices in the range 1.14-1.75. Chiral amplification was observed in R/S copolymerization. Conformational analysis revealed that the polymers form a tightly twisted helical structure with a dihedral angle of 70 degrees at the single bond of the main chain.
Suzuki
Yuji
Y
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura Campus, Kyoto (Japan).
Shiotsuki
Masashi
M
Sanda
Fumio
F
Masuda
Toshio
T
D002942:Circular Dichroism; D008968:Molecular Conformation; D015394:Molecular Structure; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D053279:Polyynes / Q000138:chemical synthesis* / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
D011108:Polymers; D053279:Polyynes; D012238:Rhodium