Synthesis and Characterization of Monodisperse Oligo(fluorene-co-bithiophene)s
- 4 July 2007
- journal article
- research article
- Published by Wiley in Chemistry – A European Journal
- Vol. 13 (21), 6238-6248
- https://doi.org/10.1002/chem.200700007
Abstract
A series of monodisperse oligo(9,9‐di‐n‐octylfluorene‐co‐bithiophene)s (OFbTs) with molecular lengths of up to 19.5 nm and molecular weights up to 7025 g mol−1 has been synthesized by a divergent/convergent approach involving Stille coupling reactions. Stille coupling is quite efficient in preparing this class of oligomers, and even the molecule with nine fluorene units and eight bithiophene units (F9Th16) can be synthesized in a yield as high as 70 %. Because of easy functionalization of the thiophene ring at its α position, no additional protecting group allowing activation for further reaction is necessary. However, the synthetic routes must be optimized to eliminate contamination of the targeting compounds with the homocoupling product of the organotin reagents. Synthesis of the longest oligomer F13Th24 in a relative large quantity is limited by its low yield due to the pronounced ligand‐exchange side reactions of the starting materials and reaction intermediates. All oligomers longer than F4Th6 are nematic mesomorphs and exhibit enhanced glass transition temperature and clearing point with increasing molecular length, as revealed by differential scanning calorimetry and polarizing optical microscopy. Absorption and photoluminescence (PL) measurements reveal that OFbTs are well‐conjugated systems with an effective conjugation length longer than the length of F13Th24.Keywords
This publication has 77 references indexed in Scilit:
- Effect of molecular weight on electronic, electrochemical and spectroelectrochemical properties of poly(3,3″-dioctyl-2,2′∶5′,2″-terthiophene)Journal of Materials Chemistry, 2006
- Star-shaped perylene–oligothiophene–triphenylamine hybrid systems for photovoltaic applicationsJournal of Materials Chemistry, 2005
- Photoluminescence Properties of Discrete Conjugated Wires Wrapped within Dendrimeric Envelopes: “Dendrimer Effects” on π‐Electronic ConjugationAngewandte Chemie-International Edition, 2004
- Strongly Polarized and Efficient Blue Organic Light‐Emitting Diodes Using Monodisperse Glassy Nematic Oligo(fluorene)sAdvanced Materials, 2003
- Efficient solid-phase synthesis of regioregular head-to-tail-coupled oligo(3-alkylthiophene)s up to a dodecamerJournal of the Chemical Society, Perkin Transactions 1, 2000
- Monodomain alignment of thermotropic fluorene copolymersLiquid Crystals, 1999
- Lineare monodisperse π-konjugierte Oligomere: mehr als nur Modellverbindungen für PolymereAngewandte Chemie, 1999
- Synthesis and Properties of the Longest Oligothiophenes: The Icosamer and HeptacosamerThe Journal of Organic Chemistry, 1998
- What does materials science learn from conjugated oligomers?Advanced Materials, 1998
- Novel oligo(phenylenevinylenes): models for the charging of extended .pi. chainsJournal of the American Chemical Society, 1991