A facile one-pot synthesis of end-functionalized star polymers consisting of PFVs has been achieved by olefin metathesis and Wittig-type coupling.

Optical properties of three types of terthiophene (3T) functionalized conjugated triarm (star-shaped) polymers consisting of poly(9,9-di- n -octyl-fluorene-2,7-vinylene) (PFV) arms and different [2,4,6-tri(biphenyl)benzene (TBP), 1,3,5-tri(benzyl)benzene (TBB), and triphenylamine (TPA)] cores, prepared by combined olefin metathesis with Wittig coupling, have been studied. Relative intensities [increases in the higher vibronic bands, (0, 1) fluorescence (FL)] of the fully conjugated TPA-core polymers, TPA(PFV-3T) 3 , in the fluorescence (FL) spectra in tetrahydrofuran (toluene) solution were higher than those in the other triarm polymers, TBP(PFV-3T) 3 , TBB(PFV-3T) 3 , whereas no significant differences were observed in their UV–vis spectra; notable temperature dependences were not observed in the UV–vis and FL spectra (at −5, 25, and 55 °C). Remarkable differences were not observed in the spectra in these polymer thin films, whereas λ max values red-shifted due to the formation of J -type aggregates. The observation for the time-resolved study well corresponds to results for the steady-state fluorescence measurements. The observed unique emission by the star-shaped (triarm) polymer containing the TPA core would be assumed to be due to a difference in nature of the core (higher coplanarity) compared to that of the others.

Time-resolved fluorescence anisotropy measurements were performed on three-branched star-shaped polymers, based on precisely synthesized poly­(9,9-di-n-octyl-fluorene vinylene)­s containing C6F5 end groups. The star-shaped polymers showed identical fluorescence spectra, fluorescence lifetimes, and quantum yields to those of the reference single-chain oligomer. However, a rapid fluorescence anisotropy decay was observed in two kinds of star-shaped polymers, while such decay was not seen in the corresponding single-chain oligomer. On the basis of the analysis using an incoherent hopping model, the observed rapid anisotropy decay is attributable to energy hopping processes between branches within a single polymer species, and its rate was deduced to be ca.100 ps depending upon the core part.

Precise, efficient one‐pot synthesis of star shaped (tri‐, tetra‐arm) π‐conjugated systems has been achieved by olefin metathesis of 5‐substituted‐2‐propenyl‐thiophene or N‐vinyl carbazole (arm segment) using a molybdenum‐alkylidene reagent and subsequent Wittig‐type cleavage with core segments containing aldehydes [tri(4‐formylphenyl)amine, 2,4,6‐tri(4‐formyl‐biphenyl)benzene, 1,4‐dimethoxy‐2,3,5,6‐tetra(4‐formylphenyl)‐benzene, etc.]; effects of the core and the arm have been clearly demonstrated.