Spirobifluorene units, polymers

Title Conjugated Polymers Containing Spirobifluorene Units and Use Thereof... 

Conjugated polymers containing spirobifluorene and fluorene units,... 

Spirobifluorenes have been investigated by Salbeck [100] and found to be promising materials for use in blue LEDs, and so some effort has been made to incorporate these units into polymers (Scheme 30). As poly(diarylfluorene)s have proven to be stable blue emitters it comes as no surprise to find that polymers containing spirobifluorenes such as 66 [101] and 67 [102] also produce stable blue emission. A fluorene-spirobifluorene alternating copolymer 68 has been made and was found to give stabler emission than the fluorene homopolymer 16, but green emission was still observed upon heating in air at 150 °C [103]. 

UV-vis spectroscopy showed shorter maximum absorption wavelengths for P2 (41), M2 (43), and D2 (45) than for PI (40), Ml (42), and D1 (44). This was caused by the quarterthiophene unit twisted by the thermally induced steric interaction between the spirobifluorene and the hejq l group. Both polymers showed also a broader signal, meaning that they adopted a non-planar... 

A new chiral sub-unit to have been incorporated into crowns is the 2,2 -disubstituted-9,9 -spirobifluorene moiety (98). An electrochemical investigation, using ionophore-solvent-polymer membranes, of the enantiomer selectivity of a series of chiral neutral ionophores, including some crown ethers based on (98) or 2,2 -binaphthyl units, has been published.The best selectivity was shown by... 

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