Main Group Strategies towards Functional Hybrid Materials

Showcases the highly beneficial features arising from the presence of main group elements in organic materials, for the development of more sophisticated, yet simple advanced functional materials Functional organic materials are already a huge area of academic and industrial interest for a host of electronic applications such as Organic Light-Emitting Diodes (OLEDs), Organic Photovoltaics (OPVs), Organic Field-Effect Transistors (OFETs), and more recently Organic Batteries. They are also relevant to a plethora of functional sensory applications. This book provides an in-depth overview of the expanding field of functional hybrid materials, highlighting the incredibly positive aspects of main group centers and strategies that are furthering the creation of better functional materials. Main Group Strategies towards Functional Hybrid Materials features contributions from top specialists in the field, discussing the molecular, supramolecular and polymeric materials and applications of boron, silicon, phosphorus, sulfur, and their higher homologues. Hypervalent materials based on the heavier main group elements are also covered. The structure of the book allows the reader to compare differences and similarities between related strategies for several groups of elements, and to draw crosslinks between different sections. The incorporation of main group elements into functional organic materials has emerged as an efficient strategy for tuning materials properties for a wide range of practical applications Covers molecular, supramolecular and polymeric materials featuring boron, silicon, phosphorus, sulfur, and their higher homologues Edited by internationally leading researchers in the field, with contributions from top specialists Main Group Strategies towards Functional Hybrid Materials is an essential reference for organo-main group chemists pursuing new advanced functional materials, and for researchers and graduate students working in the fields of organic materials, hybrid materials, main group chemistry, and polymer chemistry.

Table of Contents:
List of Contributors xv Preface xix 1 Incorporation of Boron into π-Conjugated Scaffolds to Produce Electron-Accepting π-Electron Systems 1 Atsushi Wakamiya 1.1 Introduction 1 1.2 Boron-Containing Five-Membered Rings: Boroles and Dibenzoboroles 2 1.3 Annulated Boroles 8 1.4 Boron-Containing Seven-Membered Rings: Borepins 11 1.5 Boron-Containing Six-Membered Rings: Diborins 14 1.6 Planarized Triphenylboranes and Boron-Doped Nanographenes 17 1.7 Conclusion and Outlook 21 References 22 2 Organoborane Donor–Acceptor Materials 27 Sanjoy Mukherjee and Pakkirisamy Thilagar 2.1 Organoboranes: Form and Functions 27 2.2 Linear D-A Systems 29 2.3 Non-conjugated D-A Organoboranes 32 2.4 Conjugated Nonlinear D-A Systems 33 2.5 Polymeric Systems 36 2.6 Cyclic D-A Systems: Macrocycles and Fused-Rings 39 2.7 Conclusions and Outlook 43 References 43 3 Photoresponsive Organoboron Systems 47 Soren K. Mellerup and Suning Wang 3.1 Introduction 47 3.1.1 Four-Coordinate Organoboron Compounds for OLEDs 47 3.1.2 Photochromism 49 3.2 Photoreactivity of (ppy)BMes2 and Related Compounds 50 3.2.1 Photochromism of (ppy)BMes2 50 3.2.2 Mechanism 51 3.2.3 Derivatizing (ppy)BMes2: Impact of Steric and Electronic Factors on Photochromism 52 3.2.3.1 Substituents on the ppy Backbone 52 3.2.3.2 Aryl Groups on Boron: Steric versus Electronic Effect 54 3.2.3.3 π-Conjugation and Heterocyclic Backbones 56 3.2.3.4 Impact of Different Donors 58 3.2.3.5 Polyboryl Species 60 3.3 Photoreactivity of BN-Heterocycles 62 3.3.1 BN-Isosterism and BN-Doped Polycyclic Aromatic Hydrocarbons (PAHs) 62 3.3.2 Photoelimination of (2-Benzylpyridyl)BMes2 62 3.3.3 Mechanism 64 3.3.4 Scope of Photoelimination: The Chelate Backbone 65 3.3.5 Strategies of Enhancing ΦPE: Metalation and Substituents on Boron 66 3.4 New Photochromism of BN-Heterocycles 68 3.4.1 Photochromism of (2-Benzylpyridyl)BMesF 2 and Related Compounds 68 3.4.2 Mechanism 70 3.5 Exciton Driven Elimination (EDE): In situ Fabrication of OLEDs 70 3.6 Summary and Future Prospects 73 References 74 4 Incorporation of Group 13 Elements into Polymers 79 Yi Ren and Frieder Jäkle 4.1 Introduction 79 4.2 Tricoordinate Boron in Conjugated Polymers 80 4.3 Tetracoordinate Boron Chelate Complexes in Polymeric Materials 87 4.3.1 N-N Boron Chelates 88 4.3.2 N-O Boron Chelates 91 4.3.3 N-C Boron Chelates 92 4.4 Polymeric Materials with B-P and B-N in the Backbone 92 4.5 Polymeric Materials Containing Borane and Carborane Clusters 97 4.6 Polymeric Materials Containing Higher Group 13 Elements 101 4.7 Conclusions 105 Acknowledgements 106 References 106 5 Tetracoordinate Boron Materials for Biological Imaging 111 Christopher A. DeRosa and Cassandra L. Fraser 5.1 Introduction 111 5.1.1 Introduction to Luminescence 111 5.1.2 Tetracoordinate Boron Dye Scaffolds 113 5.2 Small Molecule Fluorescence Imaging Agents 114 5.2.1 Bright Fluorophores 116 5.2.2 Solvatochromophores 117 5.2.3 Molecular Motions of Boron Dyes 118 5.2.3.1 Molecular Rotors 121 5.2.3.2 Turn-On Probes 121 5.3 Polymer Conjugated Materials 124 5.3.1 Dye–Polymer Systems 124 5.3.2 Oxygen-Sensing Polymers 126 5.3.3 Energy Transfer in Polymers 129 5.3.4 Conjugated Polymers 130 5.3.5 Aggregation-Induced Emission Polymers 130 5.4 Conclusion and Future Outlook 133 References 133 6 Advances and Properties of Silanol-Based Materials 141 Rudolf Pietschnig 6.1 Introduction 141 6.2 Preparation 141 6.3 Reactivity 143 6.3.1 Adduct Formation 143 6.3.2 Metallation 145 6.3.3 Condensation 146 6.4 Properties and Application 148 6.4.1 Surface Modification 148 6.4.2 Catalysis 154 6.4.3 Bioactivity 155 6.4.3.1 Monosilanols 155 6.4.3.2 Silanediols 156 6.4.3.3 Silanetriols 157 6.4.4 Supramolecular Assembly 158 References 159 7 Silole-Based Materials in Optoelectronics and Sensing 163 Masaki Shimizu 7.1 Introduction 163 7.2 Basic Aspects of Silole-Based Materials 164 7.3 Silole-Based Electron-Transporting Materials 167 7.4 Silole-Based Host and Hole-Blocking Materials for OLEDs 170 7.5 Silole-Based Light-Emitting Materials 171 7.6 Silole-Based Semiconducting Materials 175 7.7 Silole-Based Light-Harvesting Materials for Solar Cells 179 7.8 Silole-Based Sensing Materials 185 7.9 Conclusion 189 References 190 8 Materials Containing Homocatenated Polysilanes 197 Takanobu Sanji 8.1 Introduction 197 8.2 Synthesis 197 8.3 Functional Modification of Polysilanes 198 8.4 Control of the Stereochemistry of Polysilanes 199 8.5 Control of the Secondary Structure of Polysilanes 200 8.6 Polysilanes with 3D Architectures 202 8.7 Applications 203 8.8 Summary 205 References 205 9 Catenated Germanium and Tin Oligomers and Polymers 209 Daniel Foucher 9.1 Introduction 209 9.2 Oligogermanes and Oligostannanes 209 9.3 Preparation of Polygermanes 212 9.3.1 Wurtz Coupling 212 9.3.2 Reductive coupling of Dihalogermylenes 214 9.3.3 Electrochemical Reduction of Dihalodiorganogermanes and Trihaloorganogermanes 215 9.3.4 Transition Metal-Catalyzed Polymerizations of Germanes 215 9.3.4.1 Demethanative Coupling of Germanes 216 9.3.5 Photodecomposition of Germanes 218 9.3.6 Properties and Characterization of Polygermanes 218 9.3.6.1 Thermal Properties of Polygermanes 218 9.3.6.2 Electronic Properties of Polygermanes 219 9.4 Preparation of Polystannanes 220 9.4.1 Wurtz Coupling 220 9.4.2 Electrochemical Synthesis 221 9.4.3 Dehydropolymerization 224 9.4.4 Alternating Polystannanes 227 9.4.5 Properties and Characterization of Polystannanes 227 9.4.5.1 Sn NMR 227 9.4.5.2 Thermal and Photostability 228 9.4.5.3 Electronic Properties 230 9.4.5.4 Conductivity 231 9.4.6 Molecular Modeling of Oligostannanes and Comparison of Group 14 Polymetallanes 231 9.5 Conclusions and Outlook 233 Acknowledgements 233 References 234 10 Germanium and Tin in Conjugated Organic Materials 237 Yohei Adachi and Joji Ohshita 10.1 Introduction 237 10.2 Germanium and Tin-Linked Conjugated Polymers 238 10.2.1 Germylene-Ethynylene Polymers 238 10.2.2 Fluorene- and Carbazole-Containing Germylene Polymers 240 10.2.3 Germanium- and Tin-Linked Ferrocenes and Related Compounds 241 10.3 Germanium- and Tin-Containing Conjugated Cyclic Systems 242 10.3.1 Non-fused Germoles and Stannoles 242 10.3.2 Dibenzogermoles and Dibenzostannoles 248 10.3.3 Dithienogermole and Dithienostannole 253 10.3.4 Other Fused Germoles 258 10.3.5 Germacycloheptatriene and Digermacyclohexadiene 259 10.4 Summary and Outlook 260 References 260 11 Phosphorus-Based Porphyrins 265 Yoshihiro Matano 11.1 Introduction 265 11.2 Porphyrins Bearing Phosphorus-Based Functional Groups at their Periphery 266 11.2.1 Porphyrins Bearing meso/β-Diphenylphosphino Groups 266 11.2.2 Porphyrins Bearing meso/β-Triphenylphosphonio Groups 269 11.2.3 Porphyrins Bearing meso/β-Diphenylphosphoryl Groups 273 11.2.4 Porphyrins Bearing meso/β-Dialkoxyphosphoryl Groups 276 11.2.5 Phthalocyanines Bearing Phosphorus-Based Functional Groups 280 11.3 Porphyrins and Related Macrocycles Containing Phosphorus Atoms at their Core 283 11.3.1 Core-Modified Phosphaporphyrins 284 11.3.2 Core-Modified Phosphacalixpyrroles 287 11.3.3 Core-Modified Phosphacalixphyrins 289 11.4 Conclusions 290 Acknowledgements 292 References 292 12 Applications of Phosphorus-Based Materials in Optoelectronics 295 Matthew P. Duffy, Pierre-Antoine Bouit, and Muriel Hissler 12.1 Introduction 295 12.2 Phosphines 296 12.2.1 Application as Charge-Transport Layer 296 12.2.2 Application as Host for Phosphorescent Complexes 299 12.2.3 Application as Emitting Materials 303 12.3 Four-Membered P-Heterocyclic Rings 306 12.3.1 Diphosphacyclobutanediyls 306 12.3.2 Phosphetes 307 12.4 Five-Membered P-Heterocyclic Rings: Phospholes 307 12.4.1 Application as Charge-Transport Layers 308 12.4.2 Application as Host for Phosphorescent Complexes 309 12.4.3 Application as Emitter in OLEDs 309 12.4.4 Dyes for Dye-Sensitized Solar Cells (DSSCs) 316 12.4.5 Donors in Organic Solar Cells (OSCs) 316 12.4.6 Application in Electrochromic Cells 317 12.4.7 Application in Memory Devices 318 12.5 Six-Membered P-Heterocyclic Rings 319 12.5.1 Phosphazenes 319 12.5.1.1 Application as Electrolyte for Solar Cells 319 12.5.1.2 Application as Host for Triplet Emitters in PhOLEDs 320 12.5.1.3 Application as Emitter for OLEDs 321 12.6 Conclusion 321 Abbreviations 322 References 324 13 Main-Chain, Phosphorus-Based Polymers 329 Klaus Dück and Derek P. Gates 13.1 Introduction 329 13.2 Polyphosphazenes 330 13.3 Poly(phosphole)s 333 13.4 Poly(methylenephosphine)s 336 13.5 Poly(arylene-/vinylene-/ethynylene-phosphine)s 341 13.6 Phospha-PPVs 343 13.7 Poly(phosphinoborane)s 345 13.8 Metal-Containing Phosphorus Polymers 347 13.9 Additional P-Containing Polymers 349 13.10 Summary 350 Acknowledgements 351 References 351 14 Synthons for the Development of New Organophosphorus Functional Materials 357 Robert J. Gilliard, Jr., Jerod M. Kieser, and John D. Protasiewicz 14.1 General Introduction 357 14.1.1 Phosphorus-Based Functional Materials 357 14.1.2 Phosphorus Allotropes 359 14.2 Phosphorus Transfer Reagents as Emerging Synthetic Approaches to Materials 360 14.2.1 Introduction to Phosphorus Transfer Reagents 360 14.2.2 Phosphaethynolate Salts 360 14.2.3 Phospha-Wittig Reagents 367 14.2.4 Phospha-Wittig–Horner Reagents 371 14.2.5 Phosphadibenzonorbornadiene Derivatives 373 14.3 Carbene-Stabilized Molecules as Phosphorus Reagents 375 14.3.1 Introduction to Carbene Phosphorus Complexes 375 14.3.2 N-Heterocyclic Carbene-Stabilized Phosphorus Complexes 375 14.3.3 Cyclic (Alkyl)(Amino) Carbene-Stabilized Phosphorus Compounds 376 14.3.4 Reactions of N-Heterocyclic Carbenes with Phosphaalkenes 377 14.4 Conclusions and Outlook 378 References 379 15 Arsenic-Containing Oligomers and Polymers 383 Hiroaki Imoto and Kensuke Naka 15.1 Introduction 383 15.2 Chemistry of Organoarsenic Compounds 384 15.3 Arsenic Homocycles 384 15.4 Development of C–As Bond Formation for Organoarsenic 15.4.1 Classical Methodologies 386 15.4.2 In Situ-Generated Organoarsenic Electrophiles from Arsenic Homocycles 387 15.4.3 In Situ-Generated Organoarsenic Nucleophiles from Arsenic Homocycles 388 15.4.4 Bismetallation Based on Arsenic Homocycles 388 15.5 Properties of Poly(vinylene-arsine)s 391 15.6 Properties of 1,4-Dihydro-1,4-diarsinines 391 15.7 Properties of Arsole Derivatives 394 15.8 Arsole-Containing Polymers 396 15.9 Conclusions 399 References 400 16 Antimony-and Bismuth-Based Materials and Applications 405 Anna M. Christianson and François P. Gabbaï 16.1 Introduction 405 16.2 Anion Binding and Sensing Applications 406 16.3 Small-Molecule Binding 418 16.4 Antimony and Bismuth Chromophores 426 16.5 Conclusion 430 References 430 17 High Sulfur Content Organic/Inorganic Hybrid Polymeric Materials 433 Jeffrey Pyun, Richard S. Glass, Michael M. Mackay, Robert Norwood, and Kookheon Char 17.1 Introduction 433 17.2 The Chemistry of Liquid Sulfur 434 17.2.1 Ring-Opening Polymerization of Elemental Sulfur 434 17.2.2 Synthesis of Inorganic Nanoparticles in Liquid Sulfur 435 17.2.3 Inverse Vulcanization of Elemental Sulfur 437 17.2.4 Transformation Polymerizations with Elemental Sulfur: Combining Inverse Vulcanization with Electropolymerization 441 17.3 Waterborne Reactions of Polysulfides 442 17.4 Controlled Polymerization with High Sulfur-Content Monomers 442 17.5 Modern Applications of High Sulfur-Content Copolymers 444 17.5.1 High Sulfur-Content Polymers as Cathode Materials for Li-S Batteries 444 17.5.2 High Sulfur-Content Polymers as Transmissive Materials for IR Thermal Imaging 445 17.6 Conclusion and Outlook 448 Acknowledgements 448 References 449 18 Selenium and Tellurium Containing Conjugated Polymers 451 Zhen Zhang, Wenhan He, and Yang Qin 18.1 Introduction 451 18.2 Selenium-Containing Conjugated Polymers 452 18.2.1 Background 452 18.2.2 Electron-Rich Homopolymers 453 18.2.3 Donor–Acceptor (D-A) Copolymers 457 18.2.3.1 Selenium-Containing Benzodithiophene-Benzothiadiazole (BDT-BT) Copolymer Derivatives 460 18.2.3.2 Selenium-Containing Benzodithiophene-Thienothiophene (BDT-TT) Copolymer Derivatives 462 18.2.3.3 Selenium-Containing Benzodithiophene-Diketopyrrolopyrrole (BDT-DPP) and Benzodithiophene-Thienopyrrole-4,6-dione (BDT-TPD) Copolymers 465 18.3 Tellurium-Containing Conjugated Polymers 467 18.3.1 Background 467 18.3.2 Synthesis of Tellurium-Containing Polymers 467 18.3.2.1 Early Examples of Insoluble Polymers 467 18.3.2.2 Tellurium-Bridge Polymers 469 18.3.2.3 Soluble Tellurophene-Containing Conjugated Polymers 469 18.3.2.4 Regio-Regular Poly(3-alkyltellurophene) 472 18.3.2.5 Other Tellurium-Containing Conjugated Polymers 473 18.3.3 Application of Tellurium-Containing Conjugated Polymers 473 18.4 Conclusions and Outlook 476 References 476 19 Hypervalent Iodine Compounds in Polymer Science and Technology 483 Avichal Vaish and Nicolay V. Tsarevsky 19.1 Introduction 483 19.1.1 Historical 483 19.1.2 Bonding in Hypervalent Iodine Compounds 484 19.1.3 Patterns of Reactivity Relevant to Applications in Polymer Science and Technology 486 19.2 Applications of Hypervalent Iodine Compounds in Polymer Science and Technology 487 19.2.1 HV Iodine Compounds as Initiators for Polymerization 487 19.2.1.1 Direct Application of HV Iodine Compounds 487 19.2.1.2 Functional Radical Initiators Generated as a result of Ligand-Exchange followed by Homolysis 493 19.2.2 Post-Polymerization Modifications using HV Iodine Compounds 495 19.2.3 HV Iodine Groups as Structural Elements in Polymers 496 19.2.3.1 Polymers with HV Iodine-Based Pendant Groups 496 19.2.3.2 HV Iodine Groups as part of the Polymer Backbone 505 19.3 Conclusions 508 Acknowledgements 508 References 508 Index