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Polymer Journal (2010) 42, 336341 & The Society of Polymer Science, Japan (SPSJ) All rights reserved 0032-3896/10 $32.00 http://www.nature.com/pj
Web End =www.nature.com/pj
ORIGINAL ARTICLE
Fluorescent Fe(II) metallo-supramolecular polymers: metal-ion-directed self-assembly of new bisterpyridines containing triethylene glycol chains
Ravindra R Pal1, Masayoshi Higuchi1,2, Yuichi Negishi3, Tatsuya Tsukuda4 and Dirk G Kurth5
We synthesized new ditopic bisterpyridine (BTPY) ligands (L2 and L4) containing triethylene glycol (TEG) chains at the ortho-position of the peripheral pyridine ring and succeeded in obtaining uorescent Fe(II) metallo-supramolecular polyelectrolytes (FeL2-MEPE and FeL4-MEPE) through complexation of Fe(II) ions with L2 and L4, respectively. The Fe(II) ion is known to quench uorescence, but FeL2-MEPE shows a retention of quantum yield that is nearly threefold higher than that of the unsubstituted analog (FeL3-MEPE). We investigated the substituent effects of TEG chains on metallo-supramolecular polymers and their uorescent and electrochemical properties in detail.
Polymer Journal (2010) 42, 336341; doi:http://dx.doi.org/10.1038/pj.2010.3
Web End =10.1038/pj.2010.3; published online 10 February 2010
Keywords: bisterpyridine; uorescence; metallo-supramolecular polymers; triethylene glycol
INTRODUCTIONp-Conjugated polymers with uorescent properties have attracted signicant attention in the elds of organic light-emitting diodes1 and plastic solar cells,2 in which, recently, much effort has been devoted to the introduction of metal ions to the backbone to tune photophysical properties by harvesting the triplet state emission.3 However, poor processing properties often prevent device application of these polymers. Recently, uorescent metallo-supramolecular polymers have become of great interest because their properties, such as solubility or viscosity, are controllable by changing the ligands and metal-ion species. In particular, the importance of metallo-supra-molecular polyelectrolytes (MEPE) based on bisterpyridine (BTPY) or its derivatives in tuning optoelectronic properties after linking with conjugated molecules has been well recognized.4 The optoelectronic properties, which largely depend on the light emission efciency of uorescent MEPE, can be tuned by the choice of metal ion and the modication of ligands. Using different metal ions57 as templates
to assemble organic building blocks into polymer chains through coordination to chelating terpyridyl units is an appealing strategy for the construction of photoluminescent materials.
Recently, we revealed the importance of structural modication of BTPY with electron-donating and -accepting groups substituted at the peripheral position in electrochemical properties of the corresponding Fe(II)-, Co(II)- and Ru(II)-MEPEs and photophysical properties of Ru(II)-MEPEs. After a successful study of the substituent effects...