Functional Organic Materials: Syntheses, Strategies and Applications

This timely overview of the syntheses for functional pi-systems focuses on target molecules that have shown interesting properties as materials or models in physics, biology and chemistry. The unique concept allows readers to select the right synthetic strategy for success, making it invaluable for a number of industrial applications. A "must have" for everyone working in this new and rapidly expanding field.

Table of Contents:
Preface xiii List of Contributors xviii Part I 3-D Carbon-rich π-Systems – Nanotubes and Segments 1 Functionalization of Carbon Nanotubes 3 Andreas Hirsch and Otto Vostrowsky 1.1 Introduction to Carbon Nanotubes – A New Carbon Allotrope 3 1.2 Functionalization of Carbon Nanotubes 4 1.3 Covalent Functionalization 5 1.3.1 Halogenation of Carbon Nanotubes 5 1.3.1.1 Fluorination of Carbon Nanotubes 5 1.3.1.2 Chlorination of Carbon Nanotubes 7 1.3.1.3 Bromination of MWCNTs 7 1.3.1.4 Chemical Derivatization of “Fluoronanotubes” 7 1.3.2 Oxidation of CNTs – Oxidative Purification 8 1.3.2.1 Carboxylation of CNTs 8 1.3.2.2 Defect Functionalization – Transformation of Carboxylic Functions 10 1.3.3 Hydrogenation of Carbon Nanotubes 19 1.3.4 Addition of Radicals 19 1.3.5 Addition of Nucleophilic Carbenes 20 1.3.6 Sidewall Functionalization Through Electrophilic Addition 21 1.3.7 Functionalization Through Cycloadditions 21 1.3.7.1 Addition of Carbenes 21 1.3.7.2 Addition of Nitrenes 22 1.3.7.3 Nucleophilic Cyclopropanation – Bingel Reaction 24 1.3.7.4 Azomethine Ylides 24 1.3.7.5 [4+2]-Cycloaddition – Diels–Alder Reaction 26 1.3.7.6 Sidewall Osmylation of Individual SWCNTs 27 1.3.8 Aryl Diazonium Chemistry – Electrochemical Modification of Nanotubes 27 1.3.9 Reductive Alkylation and Arylation of Carbon Nanotubes 29 1.3.10 Addition of Carbanions – Reactions with Alkyllithium 30 1.3.11 Covalent Functionalization by Polymerization –“Grafting To” and “Grafting From” 31 1.4 Noncovalent Exohedral Functionalization –Functionalization with Biomolecules 32 1.5 Endohedral Functionalization 42 1.6 Conclusions 44 1.7 Experimental 44 References 49 2 Cyclophenacene Cut Out of Fullerene 59 Yutaka Matsuo and Eiichi Nakamura 2.1 Introduction 59 2.2 Synthesis of [10]Cyclophenacene π-Conjugated Systems from [60]Fullerene 63 2.2.1 Synthetic Strategy 63 2.2.2 Synthesis and Characterization of [10]Cyclophenacenes 64 2.2.3 Structural Studies and Aromaticity of [10]Cyclophenacene 67 2.2.4 Synthesis of Dibenzo-fused Corannulenes 69 2.2.5 Absorption and Emission of [10]Cyclophenacenes and Dibenzo Fused Corannulenes 70 2.3 Conclusion 72 2.4 Experimental 72 References 78 Part II Strategic Advances in Chromophore and Materials Synthesis 3 Cruciform π-Conjugated Oligomers 83 Frank Galbrecht, Torsten W. B_nnagel, Askin Bilge, Ullrich Scherf and Tony Farrell 3.1 Introduction 83 3.2 Oligomers with a Tetrahedral Core Unit 85 3.3 Oligomers with a Tetrasubstituted Benzene Core 91 3.4 Oligomers with a Tetrasubstituted Biaryl Core 95 3.5 Conclusion 113 3.6 Experimental 113 Acknowledgments 115 References 116 4 Design of π-Conjugated Systems Using Organophosphorus Building Blocks 119 Philip W. Dyer and Régis Réau 4.1 Introduction 119 4.2 Phosphole-containing π-Conjugated Systems 121 4.2.1 α,α’-Oligo(phosphole)s 123 4.2.2 Derivatives Based on 1,1’-Biphosphole Units 126 4.2.3 Mixed Oligomers Based on Phospholes with Other (Hetero)aromatics 129 4.2.4 Mixed Oligomers Based on Biphospholes with other (Hetero)aromatics 137 4.2.5 Mixed Oligomers Based on Phospholes with Ethenyl or Ethynyl Units 138 4.2.6 Polymers Incorporating Phospholes 140 4.2.7 Mixed Oligomers and Polymers Based on Dibenzophosphole or Dithienophosphole 143 4.3 Phosphine-containing π-Conjugated Systems 147 4.3.1 Polymers Based on p-Phenylenephosphine Units 147 4.3.2 Oligomers Based on Phosphine–Ethynyl Units 151 4.3.3 Mixed Derivatives Based on Arylphosphino Units 155 4.4 Phosphaalkene- and Diphosphene-containing π-Conjugated Systems 161 4.5 Conclusion 168 4.6 Selected Experimental Procedures 169 References 172 5 Diversity-oriented Synthesis of Chromophores by Combinatorial Strategies and Multi-component Reactions 179 Thomas J. J. Müller 5.1 Introduction 179 5.2 Combinatorial Syntheses of Chromophores 180 5.2.1 Combinatorial Azo Coupling 181 5.2.2 Combinatorial Condensation Reactions 182 5.2.3 Combinatorial Cross-coupling Reactions 187 5.2.4 Combinatorial Coordination Chemistry 197 5.3 Novel Multi-component Syntheses of Chromophores 199 5.3.1 Multi-component Condensation Reactions 199 5.3.2 Multi-component Cross-coupling Reactions 204 5.4 Conclusion and Outlook 215 5.5 Experimental Procedures 215 References 218 6 High-yield Synthesis of Shape-persistent Phenylene–Ethynylene Macrocycles 225 Sigurd Höger 6.1 Introduction 225 6.2 Synthesis 227 6.2.1 General 227 6.2.2 The Kinetic Approach 227 6.2.2.1 Statistical Reactions 227 6.2.2.2 Template-controlled Cyclizations 238 6.2.3 The Thermodynamic Approach 251 6.3 Conclusion 254 6.4 Experimental Procedures 255 References 258 7 Functional Materials via Multiple Noncovalent Interactions 261 Joseph R. Carlisle and Marcus Weck 7.1 Introduction 261 7.2 Biologically Inspired Materials via Multi-step Self-assembly 262 7.3 Small Molecule-based Multi-step Self-assembly 265 7.4 Polymer-based Self-assembly 275 7.4.1 Main-chain Self-assembly 276 7.4.2 Side-chain Self-assembly 279 7.4.3 Macroscopic Self-assembly 287 7.5 Conclusion and Outlook 288 References 289 Part III Molecular Muscles, Switches and Electronics 8 Molecular Motors and Muscles 295 Sourav Saha and J. Fraser Stoddart 8.1 Introduction 295 8.2 Mechanically Interlocked Molecules as Artificial Molecular Machines 297 8.3 Chemically Induced Switching of the Bistable Rotaxanes 299 8.3.1 A Bistable [2]Rotaxane Driven by Acid–Base Chemistry 300 8.3.2 A pH-driven Molecular Elevator 301 8.3.3 A Molecular Muscle Powered by Metal Ion Exchange 303 8.3.4 Redox and Chemically Controlled Molecular Switches and Muscles 304 8.3.4.1 Solution-phase Switching 305 8.3.4.2 Condensed-phase Switching 306 8.3.4.3 A Solid-state Nanomechanical Device 308 8.4 Electrochemically Controllable Bistable Rotaxanes 309 8.4.1 A Benzidine/Biphenol-based Molecular Switch 310 8.4.2 Electrochemically Controlled Switching of TTF/DNP-based [2]Rotaxanes 311 8.4.2.1 Solution-phase Switching 311 8.4.2.2 Metastability of a Redox-driven [2]Rotaxane SAM on Gold Surfaces 311 8.4.2.3 A TTF/DNP [2]Rotaxane-based Electrochromic Device 313 8.4.2.4 A Redox-driven [2]Rotaxane-based Molecular Switch Tunnel Junctions (MSTJs) Device 314 8.4.3 A Redox and Chemically Controllable Bistable Neutral [2]Rotaxane 315 8.4.3.1 Electrochemical Switching 315 8.4.3.2 Chemical Switching Induced by Lithium Ion (Li+) 316 8.5 Photochemically Powered Molecular Switches 316 8.5.1 Molecular Switching Caused by Photoisomerization 317 8.5.2 PET-induced Switching of an H-bonded Molecular Motor 318 8.5.3 MLCT-induced Switching of a Metal Ion-based Molecular Motor 319 8.5.4 A Photo-driven Molecular Abacus 320 8.6 Conclusions 322 Acknowledgments 322 References 323 9 Diarylethene as a Photoswitching Unit of Intramolecular Magnetic Interaction 329 Kenji Matsuda and Masahiro Irie 9.1 Introduction 329 9.2 Photochromic Spin Coupler 331 9.3 Synthesis of Diarylethene Biradicals 333 9.4 Photoswitching Using Bis(3-thienyl)ethene 335 9.5 Reversed Photoswitching Using Bis(2-thienyl)ethene 340 9.6 Photoswitching Using an Array of Photochromic Molecules 341 9.7 Development of a New Switching Unit 344 9.8 Conclusions 348 9.9 Experimental Procedures 348 Acknowledgments 349 References 350 10 Thiol End-capped Molecules for Molecular Electronics: Synthetic Methods, Molecular Junctions and Structure–Property Relationships 353 Kasper Nørgaard, Mogens Brøndsted Nielsen and Thomas Bjørnholm 10.1 Introduction 353 10.2 Synthetic Procedures 354 10.2.1 Protecting Groups for Arylthiols 354 10.2.1.1 Synthesis of Arylthiol “Alligator Clips” 354 10.2.2 One-terminal Wires 358 10.2.3 Two-terminal Wires 359 10.2.4 Three-terminal Wires 364 10.2.5 Four-terminal Wires 365 10.2.6 Caltrops 367 10.3 Electron Transport in Two- and Three-terminal Molecular Devices 368 10.3.1 Molecular Junctions 375 10.3.1.1 Scanning Tunneling-based Molecular Junctions 375 10.3.1.2 Conducting-probe Atomic Force Microscopy 379 10.3.1.3 Solution-phase Molecular STM Junctions 380 10.3.1.4 Break Junctions 381 10.3.1.5 Crossed Wires 382 10.3.1.6 Nanopore Junctions 382 10.3.1.7 Square-tip Junctions 383 10.3.1.8 Mercury Drop Junctions 384 10.3.1.9 Particle Junctions 384 10.3.1.10 Nanowire Junctions 385 10.3.1.11 Three-terminal Single-molecule Transistors 386 10.4 Summary and Outlook 387 10.5 Experimental 388 References 389 11 Nonlinear Optical Properties of Organic Materials 393 Stephen Barlow and Seth R. Marder 11.1 Introduction to Nonlinear Optics 393 11.1.1 Introduction 393 11.1.2 Linear and Nonlinear Polarization 394 11.1.3 Second-order Nonlinear Optical Effects 396 11.1.4 Measurement Techniques for Second-order Properties, β and χ(2) 397 11.1.5 Third-order Nonlinear Optical Effects 399 11.1.6 Measurement Techniques for 2PA Cross-section, δ 401 11.2 Second-order Chromophores for Electrooptic Applications 404 11.2.1 Design of Second-order Chromophores: the Two-level Model 404 11.2.2 Other Chromophore Designs 409 11.2.3 Other Considerations 411 11.2.4 High-performance Electooptic Poled-polymer Systems 413 11.3 Design and Application of Two-photon Absorbing Chromophores 418 11.3.1 Essential-state Models for Two-photon Cross-section 418 11.3.2 Chromophore Designs 420 11.3.3 Applications of Two-photon Absorption 427 11.4 Appendix: Units in NLO 430 Acknowledgments 431 References 431 Part IV Electronic Interaction and Structure 12 Photoinduced Electron Transfer Processes in Synthetically Modified DNA 441 Hans-Achim Wagenknecht 12.1 DNA as a Bioorganic Material for Electron Transport 441 12.2 Mechanism of Hole Transfer and Hole Hopping in DNA 444 12.3 Reductive Electron Transfer and Excess Electron Transport in DNA 446 12.3.1 Strategies for the Synthesis of DNA Donor–Acceptor Systems 446 12.3.2 Chromophore Functionalization of DNA Bases via Synthesis of DNA Building Blocks 448 12.3.3 DNA Base Modifications via a Solid-phase Synthetic Strategy 452 12.3.4 Chromophores as Artificial DNA Base Substitutes 454 12.4 Results from the Electron Transfer Studies 456 12.5 Outlook: Towards Synthetic Nanostructures Based on DNA-like Architecture 460 References 463 13 Electron Transfer of π-Functional Systems and Applications 465 Shunichi Fukuzumi 13.1 Introduction 465 13.2 Efficient Electron-transfer Properties of Zinc Porphyrins 467 13.3 Efficient Electron-transfer Properties of Fullerenes 474 13.4 Photoinduced Electron Transfer in Electron Donor-Acceptor Linked Molecules Mimicking the Photosynthetic Reaction Center 477 13.5 An Orthogonal π-Donor-Acceptor Dyad Affording an Infinite CS Lifetime 485 13.6 A Long-lived ET State Acting as an Efficient ET Photocatalyst 490 13.7 Organic Solar Cells Using Simple Donor-Acceptor Dyads 494 13.8 Organic Solar Cells Composed of Multi-porphyrin/C60 Supramolecular Assemblies 499 13.9 Conclusion 506 Acknowledgments 506 References 507 14 Induced π-Stacking in Acenes 511 John E. Anthony 14.1 Introduction 511 14.2 Anthracene 512 14.2.1 Monosubstituted Anthracene 514 14.2.2 Disubstituted Anthracene 517 14.2.3 Edge-substituted Anthracenes (Anthracene Functionalized at the 1,8- or 1,8,9-Positions) 522 14.2.4 Liquid Crystalline Anthracenes 525 14.2.5 Anthracene Self-assembly: Hydrogen Bonding 526 14.3 Tetracene (Naphthacene) 528 14.3.1 Ethynyltetracenes 530 14.3.2 Tetrasubstituted Tetracenes 532 14.4 Pentacene 534 14.5 Higher Acenes 540 14.6 Conclusion 541 Acknowledgments 542 References 542 15 Synthesis and Characterization of Novel Chiral Conjugated Materials 547 Andrzej Rajca and Makoto Miyasaka 15.1 Introduction 547 15.2 Synthetic Approaches to Highly Annelated Chiral π-Conjugated Systems 548 15.2.1 Helicenes 548 15.2.1.1 Photochemical Syntheses 549 15.2.1.2 Non-photochemical Syntheses 551 15.2.2 Double Helicenes and Chiral Polycyclic Aromatic Hydrocarbons 560 15.2.3 Tetraphenylenes and π-Conjugated Double Helices 563 15.3 Barriers for Racemization of Chiral π-Conjugated Systems 567 15.4 Strong Chiroptical Properties in Absorption, Emission and Refraction 570 15.4.1 Absorption and Emission 570 15.4.2 Refraction 572 15.5 Conclusion 574 Acknowledgments 574 References 574 Index 583