Fluorene-diboronic acids

Many other PF copolymers, which do not contain a particularly electron-active moiety, but nevertheless, can improve the performance of the material in PLED have been synthesized. The Huang group [364,365] at Institute of Materials Research and Engineering (IMRE, Singapore) synthesized deep-blue copolymer 272 by Suzuki copolymerization of fluorene-diboronic acid with dibromobenzene. The emission band of 272 has a peak at 420 nm and a well-defined vibronic feature at 448 nm with a fwhm of 69 nm, and virtually no green emission,... 

FIGURE 27. Poly(boronate)s using fluorene-diboronic acids with pentaerythritol (a) and 1,2,4,5-tetrahydroxybenzene (b) have shown to act as self-repairing materials (a and b) and as a new class of wide band-gap semiconductor (b). 

A very efficient green-emitting fluorene copolymer 304 was synthesized by Shim and coworkers [390] via Suzuki coupling of dibromothieno[3,2-b]thiophene with dialkylfluorene-diboronic acid [390]. The authors compared the EL properties of this copolymer with PFO homopolymer 196 and PFO-bithiophene copolymer 295. Both the absorption and emission spectra of 304 are red-shifted compared with PFO 196 but slightly blue-shifted compared to bithiophene-based copolymer 295. PLEDs fabricated in the configuration ITO/ PEDOT/304/LiF/Al showed a pure green emission (CIE . v 0.29, r 0.63) close to the... 

This monomer, also named 9,9-dihexylfluorene-2,7-diboronic acid bis(l,3-propanediol) ester, is commercially available. The propanediol or pinacol boronate esters of dialkylfluorenes with different alkyl chain lengths are also commercially available products, and these compounds can be used directly in the following Suzuki polymerization. However, the given synthetic procedures for boronate ester monomers will be useful for preparing new fluorene monomers, which are not commercially available. 

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