SYNTHESIS AND FINE-TUNING THE EMISSION PROPERTIES OF NEW AMPHIPHILIC CONJUGATED POLYMERS CHINNAPPAN BASKAR NATIONAL UNIVERSITY OF SINGAPORE 2004 SYNTHESIS AND FINE-TUNING THE EMISSION PROPERTIES OF NEW AMPHIPHILIC CONJUGATED POLYMERS CHINNAPPAN BASKAR (M.Sc., IIT MADRAS) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMISTRY NATIONAL UNIVERSITY OF SINGAPORE 2004 Dedicated to my beloved parents i Dedicated to my beloved teachers and inspirational minds “If I have been able to see further, it was only because I stood on the shoulders of giants.” - Sir Isaac Newton (1642-1727) ii Acknowledgements Life on Earth is a journey, starts as well as ends with Almighty, like cyclic reactions. During this journey, we are blessed with invaluable teachers and well wishers. It is very difficult to forget important events, ups and downs, achievements, excellent collaborators, contributors, great inspirational minds, and the land of harvest. At the end of my journey to PhD, it is a great pleasure to acknowledge people, who have supported my growth. First and above all I would like to thank Dr. Suresh Valiyaveettil for his invaluable guidance throughout my PhD research work. I thank Prof Lai Yee Hing and Prof Leslie Harrison for their interest in serving on my advisory committee. I would like to thank Prof Jagadese J. Vittal, Prof Chuah Gaik Khuan, Dr. John Yip and Dr. Yang Daiwen for their support as my thesis committee. My heartfelt thanks to Prof Hardy Chan (Vice Dean, Faculty of Science), Prof Andrew Wee (Vice Dean), Prof Xu Guo Qin (Vice Dean), Prof Tan Eng Chye (Dean), Prof Lai Choy Heng and Prof Andy Hor for their support and encouragement during my contributions in Science Graduate Committee (SGC), Graduate Students Society (GSS), and Chemistry Graduate Club (CGC). My special thanks to Prof Hian Kee Lee (Head, Chemistry), Prof Ng Siu Choon (Deputy Head) and Prof Leung Pak Hing (Deputy Head). iii My sincere gratitude to Prof Seeram Ramakrishna (Dean, Faculty of Engineering), Prof Senthil Kumar (Assitant Dean, FoE), Prof Goh Suat Hong (Chemistry), Prof Ji Wei (Physics), Prof Perera Conrad (Chemistry), Prof B. V. R. Chowdari (Physics), Prof G. V. Subba Rao (Physics), Prof K. Swaminathan (DBS) and Dr. Ignacio Segarra (S*Bio). During this period of my doctoral research program, I was certainly blessed to meet many great minds including Prof Roald Hoffmann (1981 Nobel Laureate in Chemistry), Prof Carl Djerassi (Stanford University, USA), Prof C. N. R. Rao (President, JNCAR, Bangalore), Prof Alan Heeger (2000 Nobel Laureate in Chemistry), Prof Hideki Shirakawa (2000 Nobel Laureate in Chemistry), Prof John C. Warner (University of Massachusetts Boston, USA), Dr. Paul Anastas (Director, Green Chemistry Institute, American Chemical Society, USA), Dr. Dennis Hjeresen (Former Director, Green Chemistry Institute, American Chemical Society, USA) and Dr. Mary Kirchhoff (Assistant Director, Green Chemistry Institute, American Chemical Society, USA). My sincerest thanks to all of them for their suggestion, motivation and inspiration. My thanks are also to Prof K. V. Ramanujachary (Rowan University, USA), Prof R. K. Sharma (University of Delhi, India), Prof B. Viswanathan (IIT Madras), and Prof G. Sundararajan (IIT Madras) for their informal discussion and encouragements during their journey in Singapore. I would like to thank Prof Bengt Nordén (Member, The Royal Swedish Academy of Sciences, Chairman, The Nobel Committee for Chemistry in 2000, Nobel Foundation), iv Ms. Birgitta Sandell (Assistant, The Royal Swedish Academy of Sciences) and Ms. Elin Stenbom (Assistant, The Royal Swedish Academy of Sciences) for their support to include the year 2000 Nobel Prize Presentation in Chemistry in my thesis and regular Nobel Posters. My sincerest thanks also go to Prof M. S. Subramanian (My graduate mentor, IIT Madras) and Prof Xavier Machado (My undergraduate teacher, St. Joseph’s College, Trichy, India) for their invaluable suggestion, motivation and encouragement. I want to thank many people without whom I would not have been able to complete the work presented in this thesis. I want to warmly thank all the support staff of the chemistry department in the main office, NMR, MS, Elemental Analysis, X-ray crystallography facilities, chemical stores, Honors lab, analytical lab, organic lab, and in the glassblowing shops. I would like to acknowledge the Department of Chemistry for their hospitality and encouragement on my graduate study. I wish to thank all of my past and present colleagues of the Dr. Suresh Group. I extend my special thanks to my friends especially Felix Lawrence, Lakshmanan, Skanth, Karen, Nacha, Hendry Elim, Kangueane, Arockiam and Peter, classmates and housemates. v I would like to specially thank my parents, brothers (Doss and Julian), and my uncle Sebastian for all the moral and financial support selflessly provided throughout my career. I would like to thank my sister, Ammu Margaret, who stayed up with me over the phone when I was stressed out, encouraged me when I was down, prayed for me when I didn’t think to pray for myself and believed in me when I didn’t believe in myself. Last but not least, I would like to thank God. “So, whatever you eat or drink, or whatever you do, everything for the glory of God.” – I Corinthians 10:31 (Holy Bible) CHInNaPPaN BaSKAr May 22, 2004 Saturday vi Table of Contents i Dedication Acknowledgements iii Table of Contents vii Summary xii List of Monomers and Polymers Synthesized in this Thesis xvi List of Figures xxi List of Schemes xxiii List of Tables xxiv Glossary of Abbreviations and Symbols xxv Opening Quotations xxxii Chapter Introduction: The Art and Science of Conjugated Polymers 1.1 Prologue 1.2 Genesis of Conjugated Polymers 1.3 A Case History of Poly(p-phenylene)s PPPs 13 1.4 Pyridine incorporated conjugated polymers 23 1.5 Bipyridine incorporated conjugated polymers 28 vii 1.6 Poly(m-phenylene)s (PMPs) 33 1.7 Aim of the project 37 1.8 References 38 Chapter Amphiphilic Poly(p-phenylene)s 75 2.1 Introduction 76 2.2 Synthesis of polymers 77 2.3 Characterization of polymers 79 2.4 Optical and ionochromic properties of polymers 81 2.5 Conclusions 89 2.6 References 90 Chapter Pyridine Incorporated Amphiphilic Conjugated Polymers 94 3.1 Introduction 95 3.2 Synthesis of polymers 98 3.3 Characterization of polymers 101 3.4 Optical Properties 103 Influence of hydroxyl groups 103 3.4.1 viii Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Table A-1. Absorption maxima of non-hydroxyl-containing conjugated polymersa Conjugated Polymers Absorption maxima (nm) References 1,2 R = C8H17 λmax = 336 nm 3-5 n λmax = 336 nm R O n R = C12H25 λmax = 334 nm R = C16H33 λmax = 334 nm R n R = C6H13 λmax = 300 nm R = H λmax = 345 nm (in DMF) R = C4H9 λmax = 336 nm (in CH2Cl2) R = C8H17 λmax = 336 nm (in CH2Cl2) R = C12H25 λmax = 336 nm (in CH2Cl2) R R = C6H13 λmax = 247 nm (in cyclohexane) R O n O R = R λmax = 335 nm (in CH2Cl2) = R λmax = 331 nm (in CHCl3) a Examples given here based on the derived polymers mentioned on the thesis 172 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Table A-1. Absorption maxima of non-hydroxyl-containing conjugated polymers (Continued) Conjugated Polymers Absorption maximum (nm) References λmax = 373 nm (in HCOOH) 10-12 n N λmax = 360 nm [in (CF3)2CHOH] H3 C n n N 12 λmax = 310 nm (in HCOOH) 12 λmax = 340 nm (in HCOOH) 12, 13 C H3 λmax = 320 nm (in HCOOH) N n N C H3 λmax = 319 nm (in CHCl3) λmax = 323 nm (in THF) λmax = 321 nm (in benzene) 173 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Table A-1. Absorption maxima of non-hydroxyl-containing conjugated polymers (Continued) Conjugated Polymers References λmax = 382 nm (in HCOOH) 14 λmax = 366 nm (in HCOOH) 14 λmax = 327 nm (in HCOOH) 15 λmax = 396 nm (in HCOOH) 15 N n Absorption maximum (nm) n N N H1 C n N H1 C e M O n N O e M H1 C O n N λmax = 373 nm (in CHCl3) 16-19 O C H1 174 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Table A-1. Absorption maxima of non-hydroxyl-containing conjugated polymers (Continued) Conjugated Polymers Absorption maximum (nm) References λmax = 373 nm (in HCOOH) 20,21 N n N N n H3 C C H3 N λmax = 380 nm λmax = 349 nm (in HCOOH) 22 λmax = 350 nm (in HCOOH) 22 n H6 C N N H1 C λmax = 320 nm (in CH2Cl2) H1 C N n N λmax = 322 nm (in CHCl3) 23 H1 C H2 C O λmax = 313 nm (in THF) 24,25 n 175 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers References 1. Kaeriyama, K. In Photonic Polymer Systems: Fundamentals, Methods, and Applications; Wise, D. L., Wnek, G. E., Trantolo, D. J., Cooper, T. M., Gresser, J. D.; Marcel Dekker: New York, 1998; pp 33-60. 2. Scherf, U.; Müllen, K. ACS Symp. Seri. 1997, 672, 358-380. 3. Chen, S. –A.; Chao, C. –I. Synth. Met. 1996, 79, 93-96. 4. Yang, Y.; Pei, Q.; Heeger, A. J. Synth. Met. 1996, 78, 263-267. 5. Yang, Y.; Pei, Q.; Heeger, A. J. J. Appl. Phys. 1996, 79, 934-939. 6. Vahlenkamp, T.; Wegner, G. Macromol. Chem. Phys. 1994, 195, 1933-1952. 7. Yamamoto, T.; Kimura, T.; Shiraishi, K. Macromolecules 1999, 32, 8886-8896. 8. Remmers, M.; Schulze, M.; Wegner, G. Macromol. Rapid Commun. 1996, 17, 239-252. 9. Fiesel, R.; Scherf, U. Acta Polym. 1998, 49, 445-449. 10. Yamamoto, T.; Takeuchi, M.; Kubota, K. J. Polym. Sci., Part B: Polym. Phys. 2000, 38, 1348-1351. 11. Sinha, S.; Rothe, C.; Beeby, A.; Horsburgh, L. E.; Monkman, A. P. Synth. Met. 2003, 135-136, 371-372. 12. Yamamoto, T.; Maruyama, T.; Zhou, Z. -H.; Ito, T.; Fukuda, T.; Yoneda, Y.; Begum, F.; Ikeda, T.; Sasaki, S.; Takeoe, H.; Fukuda, A.; Kubota, K. J. Am. Chem. Soc. 1994, 116, 4832-4845. 13. Maruyama, T.; Kubota, K.; Yamamoto, T. Macromolecules, 1993, 26, 40554057. 176 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers 14. Yamamoto, T.; Zhou, Z-H.; Kanbara, T.; Shimura, M.; Kizu, K.; Maruyama, T.; Nakamura, Y.; Fukuda, T.; Lee, B. L.; Ooba, N.; Tomaru, S.; Kurihara, T.; Kaino, T.; Kubota, K.; Sasaki, S. J. Am. Chem. Soc. 1996, 118, 10389-10399. 15. Wang, C.; Kilitziraki, M.; MacBride, J. A.; Bryce, M. R.; Horsburgh, L. E.; Sheridan, A. K.; Monkman, A. P.; Samuel, D. W. Adv. Mater. 2000, 12, 217-222. 16. Losurdo, M.; Giangregorio, M. M. M.; Capezzuto, P.; Bruno, G.; Babudri, F.; Colangiuli, D.; Farinola, G. M.; Naso, F. Macromolecules 2003, 36, 4492-4497. 17. Ng, S. –C.; Lu, H. –F.; Chan, H. S. O.; Fujii, A.; Laga, T.; Yoshina, K. Adv. Mater. 2000, 12, 1122-1125. 18. Liu, H. –F.; Chan, H. S. O.; Ng, S. –C.; Yoshino, K. Synth. Met. 2001, 119, 601602. 19. Ootake, R.; Fujisawa, T.; Sonoda, T.; Fujii, A.; Laga, T.; Lu, H. –F. Chan, H. S. O.; Ng, S. C.; Yoshino, K. Synth. Met. 2001, 119, 593-594. 20. Yamamoto, T.; Maruyama, T.; Ikeda, T.; Sisido, M. J. Chem. Soc., Chem. Commun. 1990, 1306-1307. 21. Maruyama, T.; Yamamoto, T. J. Phys. Chem. B 1997, 101, 3806-3810. 22. Maruyama, T.; Yamamoto, T. Synth. Met. 1995, 69, 553-554. 23. Frank, W.; Wasgindt, M.; Pautzsch, T.; Klemm, E. Macromol. Chem. Phys. 2001, 202, 980-984. 24. Reddinger, J. L.; Reynolds, J. R. Macromolecules 1997, 30, 479-481. 25. Kang, B. S.; Seo, M. –L.; Jun, Y. S.; Lee, C. K.; Shin, S. C. Chem. Commun. 1996, 1167-1168. 177 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Figure A-1. TG curve of 301; heating rate: 10 K/min under nitrogen 178 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Figure A-2. TG curve of 302; heating rate: 10 K/min under nitrogen 179 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Figure A-3. TG curve of 303; heating rate: 10 K/min under nitrogen 180 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Figure A-4. TG curve of 304; heating rate: 10 K/min under nitrogen 181 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Figure A-5. TG curve of 305; heating rate: 10 K/min under nitrogen 182 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Figure A-6. TG curve of 306; heating rate: 10 K/min under nitrogen 183 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Figure A-7. TG curve of 401; heating rate: 10 K/min under nitrogen 184 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Figure A-8. TG curve of 402; heating rate: 10 K/min under nitrogen 185 Appendix: Synthesis and Fine-tuning the Emission Properties of New Amphiphilic Conjugated Polymers Figure A-9. TG curve of 403; heating rate: 10 K/min under nitrogen 186 Concluding Quotations “Science serves humanity only when it is joined to conscience” - Pope John Paul II “This is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning.” – Sir Winston Churchill "With the spirit of love, dedication, will power, creativity, and hard work; everything is possible in the world.” – BaSKAr, C. 187 [...]... Absorption maxima of non-hydroxyl-containing 172 conjugated polymers TG curves of 301-403 178 xi Summary SYNTHESIS AND FINE- TUNING THE EMISSION PROPERTIES OF NEW AMPHIPHILIC CONJUGATED POLYMERS By Chinnappan Baskar May 2004 Since the discovery of conducting polymers in the late 1970’s, research efforts were focused on synthesis and characterization of novel polymers with π -conjugated backbone due to their interesting... of polymers 401 and 402 133 in THF Figure 6-1 Evolution of hydroxylated polyphenylenes (HPP)s 161 Figure A 1-9 TG curves of 301-403 178 xxii List of Schemes Scheme 2-1 Synthesis of polymers 201a-c 78 Scheme 3-1 Synthesis of polymers 301 and 302 99 Scheme 3-2 Synthesis of polymer 303 100 Scheme 4-1 Synthesis of polymers 401 and 402 130 Scheme 4-2 Synthesis of polymer 403 131 xxiii List of Tables Table... Conjugated Polymers Chapter 1 Introduction: The Art and Science of Conjugated Polymers Figure 1-1 The art and science of conjugated polymers Inside the square: Classical structure of conjugated polymer (CP) backbone and types of CP; Outside the square: Applications of CP 1 Chapter 1: The Art and Science of Conjugated Polymers 1.1 Prologue1 “Your Majesties, Your Royal Highnesses, Ladies and Gentlemen,... Comparison of properties of polymers 107 3.4.3 Solvatochromic behavior of polymers 107 3.4.4 Effect of protonation and deprotonation of polymers 110 3.4.5 Influence of base 113 3.4.6 Metal complexation of polymers 115 3.5 Conclusions 117 3.6 References 118 Chapter 4 Bipyridine Incorporated Conjugated Polymers 125 4.1 Introduction 126 4.2 Synthesis of polymers 129 4.3 Characterization of polymers 132... solvents such as chloroform, toluene, THF and DMF Optical properties of synthesized copolymers were investigated using chloroform, THF and HCOOH All the polymers showed interesting optical properties and possessed sensitivity to various metal ions such as Cu2+, Mn2+, and Fe3+ It was found that the absorption and emission maxima of the polymers could easily be fine- tuned by varying solvents and metal ions... parts: Prologue (with the year 2000 Nobel Prize Presentation in Chemistry), classification of conjugated polymers, a case history of PPPs with the examples of PPP and PPP related structures, pyridine incorporated conjugated polymers, bipyridine incorporated conjugated polymers, PMPs, and aim of the project Chapter 2 is focused on a series of optically tunable amphiphilic conjugated polymers, poly(2-hydroxy-5-alkoxy-p-phenylene)... belongs to the world, and is of no country and of no age The more we know, the more we feel our ignorance; the more we feel how much remains unknown; and in philosophy, the sentiment of the Macedonian hero can never apply,- there are always new worlds to conquer.” – Sir Humphry Davy (1778-1829) "I am young and avid for glory." – Antoine Lavoisier (1743-1794) xxxii Chapter 1: The Art and Science of Conjugated. .. HCl and aqueous NaOH in THF Figure 3-5 Proton Transfer from the excited cation of polymer 301 to 112 a base B Figure 3-6 UV/Vis spectra of polymers 301 and 303 without and with 113 aqueous NaOH in DMF Figure 3-7 Emission spectra of polymers 301 and 303 without and 114 with aqueous NaOH in DMF Figure 4-1 Molecular structure of the polymers 401-403 128 Figure 4-2 Absorbance and emission spectra of polymers. .. Poly(1-hydroxy-4-dodecyloxy-p-phenylene) (201a) 152 Synthesis of polymers 301-306 153 5.4.1 2,5-Dibromo-1, 4-dibenzyloxy benzene (312) 153 5.4.2 1,4-Dibenzyloxy-2,5-bisboronic acid (313) 153 5.4.3 Synthesis of Polymer 304 154 5.4.4 Synthesis of Polymer 301 155 5.4.5 Synthesis of Polymer 305 156 5.4.6 Synthesis of Polymer 302 156 References 157 5.4 5.5 x Chapter 6 Conclusions and Suggestions for the future work 158 6.1 Conclusions... (TFA) Thermogravimetric analysis (TGA) results showed that they had good thermal stability in both nitrogen and air atmosphere The optical properties of these novel polymers were closely related to the architectures of the backbone and studied using different solvents Polymers with pyridine and bipyridine were showed positive solvatochromic effect The target polymers exhibited different absorption/emission . SYNTHESIS AND FINE- TUNING THE EMISSION PROPERTIES OF NEW AMPHIPHILIC CONJUGATED POLYMERS CHINNAPPAN BASKAR NATIONAL UNIVERSITY OF SINGAPORE 2004 SYNTHESIS AND. maxima of non-hydroxyl-containing conjugated polymers TG curves of 301-403 172 178 xii Summary SYNTHESIS AND FINE- TUNING THE EMISSION PROPERTIES OF NEW AMPHIPHILIC CONJUGATED POLYMERS. SYNTHESIS AND FINE- TUNING THE EMISSION PROPERTIES OF NEW AMPHIPHILIC CONJUGATED POLYMERS CHINNAPPAN BASKAR (M.Sc., IIT MADRAS) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY