Synthesis of Poly(arylene vinylene)s with Different End Groups by Combining Acyclic Diene Metathesis Polymerization with Wittig‐type Couplings

Abstract

A series of end-functionalized poly(9,9'-di-n-octylfluorene vinylene)s (EF-PFVs) with different end groups were obtained by 1) synthesizing EF-PFV with vinyl end groups by acyclic diene metathesis (ADMET) polymerization with a molybdenum catalyst and termination with an aldehyde and 2) subsequent olefin metathesis of the vinyl group with the molybdenum catalyst followed by Wittig-type coupling with another aldehyde. The exclusive formation of EF-PFVs containing a vinyl end group by the ADMET polymerization was confirmed by grafting PEG, and by the synthesis of amphiphilic triblock copolymers by combining atom transfer radical polymerization from the PFV chain end with PEG grafting through a click reaction. Various EF-PFVs with different end groups, such as C F , pyridyl, ferrocenyl, and terthiophene, have thus been prepared. Their fluorescence spectra (e.g., intensities, emission wavelengths) were influenced by the end groups and the length of the conjugation.

Well‐Defined End‐Functionalized Conjugated Polymers/Oligomers Exhibiting Unique Emission Properties through the End Groups: The Exclusive Synthesis by Combined Olefin Metathesis with Wittig‐type Coupling

“…As described above, the fluorescence spectra in PFV‐Ar 2 were affected by the end groups . Placing ferrocene (Fc) moiety into the PFV chain ends (expressed as PFV‐Fc 2) caused a drastic quenching of photoluminescence ( Figure ), probably due to an exciton transfer to the Fc units.…”

“…In order for the exclusive end‐functionalization (to complete olefin metathesis with the vinyl chain ends for subsequent treatment with aldehyde), Mo‐cat should be further added after the polymerization. This is because that the polymerization method afforded PFVs containing molybdenum–alkylidene species at only one polymer chain end . Since various aldehydes can be used for the end‐modification, the method could be applied for synthesis of various end‐modified poly(arylene vinylene)s.…”

“…This is because that the polymerization method afforded PFVs containing molybdenumalkylidene species at only one polymer chain end. [23] Since various aldehydes can be used for the end-modification, the method could be applied for synthesis of various end-modified poly(arylene vinylene)s.…”

“…are highly affected by called defect (such as halogen [and/or palladium] contaminated, regio‐/stereo‐irregularity, cross‐linking [through coupling reactions], sulfur remained in the main chain, etc.). It has also been revealed recently that the properties are influenced by the end groups, as demonstrated in poly(fluorene)s and poly(9,9‐dialkyl‐fluorene‐2,7‐vinylene)s (PFVs) . Moreover, it has been widely recognized that their fundamental properties are affected by the interchain interactions (such as supramolecular, nano/meso scale organization) .…”

“…It has also been revealed recently that the properties are influenced by the end groups, as demonstrated in poly(fluorene)s [9][10][11][12][13][14][15][16][17][18] and poly(9,9-dialkylfluorene-2,7-vinylene)s (PFVs). [19][20][21][22][23] Moreover, it has been widely recognized that their fundamental properties are affected by the interchain interactions (such as supramolecular, nano/meso scale organization). [24][25][26][27][28][29][30] Therefore, synthesis of defectfree conjugated polymers containing well-defined end groups by development of new method and/or methodology should thus be an important subject.As shown in Scheme 1, poly(arylene vinylene)s such as poly(p-phenylene vinylene)s (PPVs) and PFVs have been prepared by i) polycondensation in the presence of tetrahydrothiophene, [31,32] ii) Gilch polymerization in the presence of KO t Bu, [33][34][35] iii) Heck coupling using Pd catalyst, [36,37] and iv) Horner-Wittig-Emmons (HWE) reactions.…”