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Mario Leclerc and Jean-Francois Morin

Design and Synthesisof Conjugated Polymers

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Edited by Mario Leclerc and Jean-Francois Morin

Design and Synthesisof Conjugated Polymers

The Editors

Prof. Mario LeclercCERMADepartement de ChimieUniversite LavalQuebec CityQuebec, G1V 0A6Canada

Prof. Jean-Francois MorinCERMADepartement de ChimieUniversite LavalQuebec CityQuebec, G1V 0A6Canada

All books published by Wiley-VCH arecarefully produced. Nevertheless, authors,editors, and publisher do not warrant theinformation contained in these books,including this book, to be free of errors.Readers are advised to keep in mind thatstatements, data, illustrations, proceduraldetails or other items may inadvertently beinaccurate.

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2010 WILEY-VCH Verlag GmbH & Co.KGaA, Weinheim

All rights reserved (including those oftranslation into other languages). No partof this book may be reproduced in anyform – by photoprinting, microfilm, or anyother means – nor transmitted or translatedinto a machine language without writtenpermission from the publishers. Registerednames, trademarks, etc. used in this book,even when not specifically marked as such,are not to be considered unprotected by law.

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Printed in the Federal Republic of GermanyPrinted on acid-free paper

ISBN: 978-3-527-32474-3

V

Contents

Preface XIList of Contributors XIII

1 Synthesis and Functionality of Substituted Polyacetylenes 1Jianzhao Liu, Jacky W. Y. Lam, and Ben Zhong Tang

1.1 Introduction 11.2 Polymer Syntheses 21.2.1 Catalysts 21.2.2 Polymerization Behaviors 41.2.3 Polymer Reactions 51.3 Functional Properties 71.3.1 Electrical Conductivity and Photoconductivity 81.3.2 Liquid Crystallinity 141.3.3 Luminescence 181.3.4 Fluorescence Sensing 251.3.5 Patterning and Imaging 251.3.6 Chromism 271.3.7 Optical Activity 281.3.8 Supramolecular Assembly 301.3.9 Optical Nonlinearity 311.3.10 Biological Compatibility 361.4 Conclusions and Prospects 38

Acknowledgments 40References 40

2 Suzuki Polycondensation: A Powerful Tool for Polyarylene Synthesis 45Junji Sakamoto, Matthias Rehahn, and A. Dieter Schluter

2.1 Introduction 452.2 General Remarks 462.3 How to Do an SPC and Aspects of Characterization 482.3.1 Monomer Purity, Stoichiometry, and Solvents 482.3.2 Brief Note on Optimization 52

Design and Synthesis of Conjugated Polymers. Edited by Mario Leclerc and Jean-Francois MorinCopyright 2010 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 978-3-527-32474-3

VI Contents

2.3.3 Reduced Catalyst Amount and Product Purification 552.3.4 Molar Mass Determination 582.4 Methodological Developments 602.4.1 Boronic Acid/Boronate Monomers 602.4.2 Boron-Based Ate Complexes 622.4.3 Halo and Related Monomers 632.4.4 Catalysts 642.4.5 Chain Growth SPC 652.4.6 Microwave and Technical Scale Microreactor Applications 672.5 Selected Classes of Polyarylenes and Related Polymers 692.5.1 Poly(para-phenylene)s 692.5.2 Polyfluorenes 722.5.3 Poly(para-meta-phenylene)s 732.5.4 Shielded Polyarylenes 752.5.5 Miscellaneous 762.6 Conclusions and Outlook 81

Acknowledgments 82References 82

3 Advanced Functional Regioregular Polythiophenes 91Itaru Osaka and Richard D. McCullough

3.1 Introduction 913.2 Unsubstituted Polythiophene 923.3 Poly(3-alkylthiophene)s 933.4 Head-to-Tail Regioregular Poly(3-alkylthiophene)s (rrP3ATs) 943.4.1 Design and Synthesis of rrP3ATs 943.4.1.1 McCullough Method 973.4.1.2 Rieke Method 973.4.1.3 GRIM Method 973.4.1.4 Other Methods 993.4.2 Mechanism of the Nickel-Catalyzed Polymerization 993.4.3 End Group Functionalization 1003.4.3.1 Postpolymerization End Group Functionalization 1003.4.3.2 In situ End Group Functionalization 1023.4.4 Fundamental Properties of rrP3ATs 1033.4.4.1 UV–vis Absorption 1033.4.4.2 Microstructure and Morphology in Thin Films 1043.4.4.3 Electrical Conductivity 1053.4.5 rrP3ATs in Electronic Devices 1073.4.5.1 rrP3ATs in PLEDs 1073.4.5.2 rrP3ATs in OFETs 1073.4.5.3 rrP3ATs in OPVs 1133.5 Regiosymmetric Poly(alkylthiophene)s 1153.5.1 Head-to-Head–, Tail-to-Tail–Coupled Poly(alkylthiophene)s 1163.5.2 Regiosymmetric Alkylthiophene–Thiophene Copolymers 118

Contents VII

3.6 Regiosymmetric Polythiophenes with (Hetero)aromatic Rings 1203.7 Polythiophene Block Copolymers 1293.7.1 All-Conjugated rrP3AT-Based Block Copolymers 1303.7.2 Conjugated–Nonconjugated rrP3AT-Based Block Copolymers 1323.8 Conclusion 138

References 139

4 Poly(phenylenevinylenes) 147Yi Pang

4.1 Introduction 1474.2 Poly(p-phenylenevinylene)s via Polymerization Methods 1484.2.1 Gilch Approach 1484.2.2 The Wessling Method 1544.3 Poly(p-phenylenevinylene)s via Polycondensation 1564.3.1 Wittig and Horner–Wadsworth–Emmons Reaction 1564.3.2 PPVs with cis-Vinylene: a Useful Tool to Modify Physical

Properties 1614.3.3 Knoevenagel Polycondensation 1614.4 Palladium-Catalyzed Cross-Coupling (Heck-, Suzuki-, and Stille

Reactions) 1644.4.1 The Heck Coupling 1644.4.2 Stille and Suzuki Coupling 1674.5 Conclusion 170

References 170

5 Poly(aryleneethynylene)s 175Brett VanVeller and Timothy M. Swager

5.1 Introduction 1755.2 Palladium-Catalyzed Polymerizations 1755.2.1 The Palladium, A 1765.2.2 The Aryl Halide, B 1775.2.3 The Amine, F, Solvent, and Copper 1775.2.4 Substituents, R1 and R2 1785.3 Different Palladium Schemes 1785.3.1 A–B Monomers 1785.3.2 Acetylene as a Monomer 1795.4 Ortho and Meta PAEs 1805.5 Macrocycles: an Introduction 1815.6 Synthesis of Monodisperse and Sequence-Specific PAEs 1825.7 Synthesis of Poly(phenylenebutadiynylenes) PPBs 1855.8 Palladium-Mediated Synthesis: Limitations and Conclusions 1875.9 Metathesis Polymerizations 1875.10 Macrocycles: the Continued Story 1895.11 Metathesis: Concluding Remarks 1915.12 Transition-Metal-Free Polymerizations 191

VIII Contents

5.13 More Complex Side-Chain Effects 1925.14 Post-Polymerization Modification 1945.14.1 Modification of the Main Chain 1945.14.2 Side-Chain Manipulation 1965.15 Characterization of Poly(aryleneethynylene) 1995.16 Conclusion 200

References 200

6 Synthesis of Poly(2,7-carbazole)s and Derivatives 205Pierre-Luc T. Boudreault, Jean-Francois Morin, and Mario Leclerc

6.1 Introduction 2056.2 Polycarbazoles 2076.2.1 Poly(3,6-carbazole)s 2076.2.2 Synthesis of 2,7-Disubstituted Carbazoles 2086.2.3 Poly(2,7-carbazole)s for Light-Emitting Diodes 2116.2.4 Poly(2,7-carbazole)s for Conducting Devices 2156.2.5 Poly(2,7-carbazole)s for Field-Effect Transistors 2166.2.6 Poly(2,7-carbazole)s for Photovoltaic Devices 2166.3 Other Carbazole Derivatives 2196.3.1 Indolo[3,2-b]carbazoles and Poly(indolo[3,2-b]carbazole)s 2196.3.2 Diindolo[3,2-b:2

′,3

′-h]carbazoles 220

6.4 Concluding Remarks 222References 223

7 Phenylene-Based Ladder Polymers 227Andrew C. Grimsdale and Klaus Mullen

7.1 Introduction 2277.2 LPPPs with Single-Atom Bridges 2297.3 LPPPs with Two-Atom Bridges 2407.4 Conclusion 242

References 243

8 Silole-Containing Conjugated Polymers 247Junwu Chen and Yong Cao

8.1 Introduction 2478.2 π -Conjugated Silole-Containing Polymers 2498.2.1 Simple Silole Ring-Based Polymers 2498.2.2 Dibenzosilole-Based Polymers 2608.2.3 Dithienosilole-Based Polymers 2678.2.4 Poly(bis-silicon-bridged stilbene) 2708.3 σ -Conjugated Silole-Containing Polymers 2718.3.1 Poly(1,1-silole)s 2718.3.2 Copolymers of 1,1-Silole 2758.4 Silole-Containing Polymers with σ –π -Mixed Conjugation 2768.5 Summary 282

Contents IX

Acknowledgments 278References 278

9 Polyfluorenes 287Qiang Zhao, Shujuan Liu, and Wei Huang

9.1 Introduction 2879.2 Chemical Structures of Polyfluorenes 2879.3 Synthesis of Polyfluorenes 2889.3.1 Synthesis of Monomers 2889.3.2 Synthesis of Polyfluorenes 2919.4 Basic Properties of Polyfluorenes 2929.4.1 Phase Behavior 2929.4.2 Basic Photophysical Properties 2939.5 Polyfluorene-Based Blue-Emitting Materials 2959.5.1 Polyfluorenes Modified by Aryl Groups at C-9 Position 2959.5.1.1 Spiro-Functionalized Polyfluorenes 2959.5.1.2 Aryl Group-Modified Polyfluorenes at C-9 Position 2979.5.2 Fluorene-Based Copolymers with Other Conjugated Units 3009.5.3 Hyperbranched Polyfluorenes 3079.5.4 Star-Shaped Polyfluorenes 3129.6 Emission Color Tuning of Polyfluorenes 3169.6.1 Polyfluorene Copolymers with Organic Chromophores 3169.6.1.1 Green-Light-Emitting Polyfluorene Derivatives 3169.6.1.2 Red-Light-Emitting Polyfluorene Derivatives 3199.6.1.3 White-Light-Emitting Polyfluorene Derivatives 3219.6.2 Polyfluorene Copolymers with Phosphorescent Heavy-Metal

Complexes 3249.6.2.1 Polyfluorene Copolymers with Ir(III) Complexes 3259.6.2.2 Polyfluorene Copolymers with Eu(III) Complexes 3299.6.2.3 Polyfluorene Copolymers with Pt(II), Re(I), Ru(II), and Os(II)

Complexes 3309.7 Polyfluorenes with Rod–Coil Structure 3339.8 Polyfluorene-Based Conjugated Polyelectrolytes 3379.8.1 Cationic Polyfluorene-Based Polymers 3399.8.2 Anionic Polyfluorene-Based Polymers 3449.9 Concluding Remarks 347

Abbreviations 347References 348

Index 357

XI

Preface

As often happens in science, the discovery of conducting polymers was somehowaccidental. A student of the Shirakawa’s laboratory was working on Ziegler-Nattapolymerization of acetylene. By accident, this student prepared a many molarconcentration of the catalyst instead of the usual millimolar concentration andobtained a polyacetylene thin film which looked like a metallic foil instead of theusual dark, powdery material. During a visit to the University of Tokyo, Prof.MacDiarmid (University of Pennsylvania) met Prof. Shirakawa and invited him tocome to Philadelphia to investigate in more detail this new form of polyacetylene.In collaboration with Prof. A.J. Heeger, this team reported in 1977 that upon partialoxidation or reduction (so-called doping reaction), the conductivity of polyacetyleneincreases more than a billionfold (up to 100 S cm−1). They eventually receivedthe 2000 Nobel Prize in chemistry for this discovery. Unfortunately, this firstconducting polymer is difficult to process and is unstable in the presence of oxygenor water.

Rapidly, many chemists investigated more stable conjugated polymers. Forinstance, in the beginning of the 1980s, a lot of studies were devoted to elec-tropolymerized polypyrroles, polythiophenes, and polyanilines. This method hasthe advantage of being able to prepare thin films of these infusible and insolu-ble conjugated polymers in one step. However, the ultimate goal was and stillremains the development of polymeric materials that combine the electrical andoptical properties of metals or semiconductors with the processing advantagesand mechanical properties of traditional polymers. For this purpose, substitutedconjugated polymers were prepared since the unsubstituted parent polymers arenot melt or solution-processable owing to strong interchain interactions and chainstiffness. First experiments indicated that the presence of bulky substituents mayinduce a twisting of the backbone which gave processable but poorly conju-gated materials with reduced electrical properties. A breakthrough occurred in1985–1986 with the syntheses of highly conjugated, conducting, and processablepoly(3-alkylthiophene)s. Following these first studies on poly(3-alkylthiophene)s, itbecame quite clear that the synthesis of well-defined head-to-tail coupled (whichshould give the lowest steric hindrance from the side chains and, possibly, a moreefficient three-dimensional packing) poly(3-alkylthiophene)s would lead to a sig-nificant improvement in the performance of these polymeric materials. Therefore,

Design and Synthesis of Conjugated Polymers. Edited by Mario Leclerc and Jean-Francois MorinCopyright 2010 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 978-3-527-32474-3

XII Preface

in attempts to bring more reliable synthetic procedures to the field of electronicmaterials, a variety of synthetic tools were utilized and allowed significant advancesin this research field. For instance, these investigations have led to the first prepara-tions of well-defined regioregular poly(3-alkylthiophene)s in 1992. The synthesis ofair-stable highly conducting poly(3,4-ethylenedioxythiophene) is another exampleof a rational design of a conjugated polymer with optimized structural and physicalproperties.

In the meantime, through collaborations with physicists and engineers, thefocus shifted from the synthesis of metallic-like conductors to the design of stablesemiconducting polymers. This new driving force is based on the aim to set upthe so-called plastic electronics where microelectronic devices can be printed ondifferent substrates. Such applications include the fabrication of light-emittingdiodes, field-effect transistors, photovoltaic cells, and the list continues to grow.For instance, the relatively young field of chemical and biological sensors based onsemiconducting conjugated polymers is expanding rapidly.

Along these lines, it is the aim of this book to review advances in the controlledand well-designed synthesis of important classes of processable conjugated poly-mers. This book includes chapters on the synthesis of well-defined and versatilepolyacetylenes (by Liu, Lam, and Tang), polyarylenes (Sakamoto, Rehahn, andSchluter), polythiophenes (Osaka and McCullough), poly(p-phenylenevinylene)s(Pang), and ladder conjugated polymers (Grimsdale and Mullen). It also cov-ers recent progress made in the synthesis of the bright poly(aryleneethynylene)s(VanVeller and Swager) and polyfluorenes (Zhao, Liu, and Huang) together withchapters on newcomers such as silole-containing conjugated polymers (Chenand Cao) and poly(2,7-carbazole) derivatives (Boudreault, Morin, and Leclerc).This book highlights recent state-of-the-art synthetic contributions but since thisresearch field is based on close interactions between chemists, physicists, andengineers, we do hope that scientists with different backgrounds will enjoy readingthese new advances in the synthesis of conjugated polymers. They will certainlyfind in the numerous reported chemical structures some inspirations for their ownresearch activities.

Finally, we cannot end this preface without expressing our gratitude to all thosewho have contributed to this book. This obviously includes all authors for theirhard, timely, and excellent work but also people at Wiley-VCH who gave us a wellappreciated support.

Quebec City, August 25, 2009 Mario LeclercJean-Francois Morin

XIII

List of Contributors

Pierre-Luc T. BoudreaultCERMADepartement de ChimieUniversite LavalQuebec CityQuebec, G1V 0A6Canada

Yong CaoSouth China University ofTechnology Institute of PolymerOptoelectronic Materials &DevicesKey Lab of Specially FunctionalMaterials of Ministry of Education381 Wushan Rd.Guangzhou 510640China

Junwu ChenSouth China University ofTechnology Institute of PolymerOptoelectronic Materials &DevicesKey Lab of Specially FunctionalMaterials of Ministry of Education381 Wushan Rd.Guangzhou 510640China

Andrew C. GrimsdaleNanyang TechnologicalUniversitySchool of MaterialsScience and Engineering50 Nanyang AvenueSingapore 639798

Wei HuangNanjing University of Posts &Telecommunications (NUPT)Jiangsu Key Laboratory forOrganic Electronics &Information Displays andInstitute of AdvancedMaterials (IAM)9 Wenyuan RoadNanjing 210046China

Jacky W. Y. LamThe Hong Kong University ofScience & TechnologyDepartment of ChemistryClear Water BayKowloonHong KongChina

Design and Synthesis of Conjugated Polymers. Edited by Mario Leclerc and Jean-Francois MorinCopyright 2010 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 978-3-527-32474-3

XIV List of Contributors

Mario LeclercCERMADepartement de ChimieUniversite LavalQuebec CityQuebec, G1V 0A6Canada

Jianzhao LiuThe Hong Kong University ofScience & TechnologyDepartment of ChemistryClear Water BayKowloonHong KongChina

Shujuan LiuNanjing University of Posts &Telecommunications (NUPT)Jiangsu Key Laboratory forOrganic Electronics &Information Displays andInstitute of AdvancedMaterials (IAM)9 Wenyuan RoadNanjing 210046China

Richard D. McCulloughCarnegie Mellon UniversityDepartment of Chemistry4400 Fifth Ave.PittsburghPA 15213USA

Jean-Francois MorinCERMADepartement de ChimieUniversite LavalQuebec CityQuebec, G1V 0A6Canada

Klaus MullenMax Planck Institute forPolymer ResearchAckermannweg 10Mainz 55128Germany

Itaru OsakaCarnegie Mellon UniversityDepartment of Chemistry4400 Fifth Ave.PittsburghPA 15213USA

and

Hiroshima UniversityDepartment of Applied Chemistry1-4-1 KagamiyamaHigashi-hiroshimaHiroshima 739-8527Japan

Yi PangThe University of AkronDepartment of ChemistryMaurice Morton Institute ofPolymer ScienceAkron190 E. Buchtel CommousOH 44325USA

Matthias RehahnDarmstadt University ofTechnologyErnst-Berl-Institute forChemical Engineering andMacromolecular SciencePetersenstraße 2264287 DarmstadtGermany

List of Contributors XV

Junji SakamotoETH ZurichDepartment of MaterialsLaboratory of Polymer ChemistryHCi G 523Wolfgang Pauli Strasse 108093 ZurichSwitzerland

A. Dieter SchluterETH ZurichDepartment of MaterialsLaboratory of Polymer ChemistryHCI J541Wolfgang Pauli Strasse 108093 ZurichSwitzerland

Timothy M. SwagerMassachusetts Institute ofTechnology77 Massachusetts AvenueCambridgeMA 02139USA

Ben Zhong TangThe Hong Kong University ofScience & TechnologyDepartment of ChemistryClear Water BayKowloonHong KongChina

and

Zhejiang UniversityDepartment of PolymerScience & EngineeringZhe Da RoadHangzhou 310027China

Brett VanVellerMassachusetts Institute ofTechnology77 Massachusetts AvenueCambridgeMA 02139USA

Qiang ZhaoNanjing University of Posts &Telecommunications (NUPT)Jiangsu Key Laboratory forOrganic Electronics &Information Displays andInstitute of AdvancedMaterials (IAM)9 Wenyuan RoadNanjing 210046China