Optoeletronic properties of poly(N-alkenyl-carbazole)s driven by polymer stereoregularity

Stereoregular polymers like isotactic poly(N-butenyl-carbazole) (i-PBK), isotactic and syndiotactic poly(N-pentenyl-carbazole) (i-PPK and s-PPK), and poly(N-hexenyl-carbazole) (i-PHK and s-PHK) are synthesized using the stereospecific homogeneous "single site" Ziegler-Natta (Z-N) catalysts: rac-dimethylsilylbis(1-indenyl)zirconium dichloride (1)/methylaluminoxane (MAO) and diphenylmethylidene(cyclopentadienyl)-(9-fluorenyl)zirconium dichloride (2)/MAO. Catalytic activity is rationalized by density functional theory (DFT) calculations. All synthesized polymers are fully characterized by NMR, thermal, wide-angle X-ray diffraction, and fourier transform infrared spectroscopy analysis. Fluorescence measurements on isotactic and syndiotactic polymer films indicate that all polymers give rise to excimers, both "sandwich-like" and "partially overlapping." Excimer formation is essentially driven by the polymer tacticity. Isotactic polymers generate both sandwich-like and partially overlapping excimers, while syndiotactic polymers give rise especially to partially overlapping ones. A theoretical combined molecular dynamics-time dependent DFT approach is also used to support the experimental results. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 242-251.