Aggregation-Induced Emission Fundamentals

by Tang, Ben Zhong; Qin, Anjun

• ISBN13: 9781118394304
• ISBN10: 1118394305
• Edition: 1st
• Format: Hardcover
• Copyright: 2013-10-28
• Publisher: Wiley

Summary

Aggregation-Induced Emission (AIE) is a novel photophysical phenomenon which offers a new platform for researchers to look into the light-emitting processes from luminogen aggregates, from which useful information on structure–property relationships may be collected and mechanistic insights may be gained. The discovery of the AIE effect opens a new avenue for the development of new luminogen materials in the aggregate or solid state. By enabling light emission in the practically useful solid state, AIE has the potential to expand significantly the technological applications of luminescent materials.

Aggregation-Induced Emission: Fundamentals is the first book to explore the fundamental issues of AIE, including the design, synthesis, and photophysical behavior of AIE-active molecules and polymers. The control of the morphological structures of the aggregates of AIE-active materials, and the experimental investigation and theoretical understanding of the AIE mechanism, are also covered in this volume.

Topics covered include:

• AIE in group 14 metalloles
• AIE in organic ion pairs
• Red light-emitting AIE materials
• Supramolecular structure and AIE
• AIE-active polymers
• Enhanced emission by restriction of molecular rotation
• Crystallization-induced emission enhancement
• Theoretical understanding of AIE phenomena

This book is essential reading for scientists and engineers who are designing optoelectronic materials and biomedical sensors, and will also be of interest to academic researchers in materials science and physical and synthetic organic chemistry, as well as physicists and biological chemists.

Author Biography

ANJUN QIN
Department of Polymer Science and Engineering, Zhejiang University, China

BEN ZHONG TANG
Department of Chemistry, The Hong Kong University of Science and Technology, China

Table of Contents

List of Contributors xiii

Preface xvii

1 Synthesis of Siloles (and Germoles) that Exhibit the AIE Effect 1

Joyce Y. Corey

1.1 Introduction 1

1.2 Background 2

1.3 Synthesis of Siloles 4

1.3.1 Reductive dimerization of tolan 4

1.3.2 Intramolecular cyclization of dialkynylsilanes 7

1.3.3 Intramolecular cyclization of dialkynylsilanes utilizing

borane reagents 10

1.3.4 Synthesis of siloles using transition metal reagents 12

1.4 Modification of Preformed Siloles 14

1.4.1 Reactions at silicon centers 14

1.4.2 Reactions of a ring carbon center 15

1.5 Related Germole Methodology 15

1.5.1 Germoles produced by metathesis and exchange reactions 15

1.5.2 Germoles from other methods 16

1.5.3 Photoluminescence and AIE of germoles 18

1.6 Metallaindenes and Metallafluorenes of Si and Ge 19

1.6.1 Methods for the formation of silaindenes and germaindenes 19

1.6.2 Methods for the formation of metallafluorenes 21

1.7 Oligomers and Polymers of Metalloles and Benzene-Annulated

Metalloles 25

1.7.1 Oligomers that contain silole units connected at the 1,1-

and 2,5-positions 25

1.7.2 Polysiloles and silole polymers connected through 2,5-positions 26

1.7.3 Polymers with silole pendants and hyperbranched polymers 27

1.7.4 Polybenzosiloles and ladder polymers 28

1.7.5 Polymers that contain silafluorenes 29

1.7.6 Germoles in oligomers and polymers 30

1.8 Summary and Future Directions 31

References 33

2 Aggregation-Induced Emission in Group 14 Metalloles (Siloles, Germoles, and Stannoles):

Spectroscopic Considerations, Substituent Effects, and Applications 38

Jerome L. Mullin1 and Henry J. Tracy

2.1 Introduction 38

2.1.1 The group 14 metalloles 40

2.2 Characteristics of AIE in the Group 14 Metalloles 43

2.2.1 Aryl-substituted siloles 43

2.2.2 Aryl-substituted germoles and stannoles 46

2.3 Origins of AIE in Group 14 Metalloles: Restricted Intramolecular Rotation 47

2.3.1 Effect of solvent viscosity 47

2.3.2 Effect of temperature 47

2.3.3 Room-temperature glasses 48

2.3.4 Effect of pressure 48

2.3.5 Excited-state lifetimes 48

2.3.6 Molecular geometry 49

2.3.7 Aggregate nanoparticle morphology 49

2.3.8 Internal structural control of intramolecular rotations 49

2.4 Polymer Films and Polymerized Siloles 50

2.5 Applications of AIE-Active Metalloles 52

2.5.1 Electrooptical devices 52

2.5.2 Chemical sensors 52

References 53

3 Aggregation-Induced Emission of 9, 10-Distyrylanthracene Derivatives and

Their Applications 60

Bin Xu, Jibo Zhang, and Wenjing Tian

3.1 Introduction 60

3.2 AIE Molecules Based on 9,10-Distyrylanthracene 62

3.2.1 Small molecules 62

3.2.2 Macromolecules 63

3.3 AIE Mechanism of 9,10-Distyrylanthracene Molecule Systems 64

3.4 Application of AIE Luminogens Based on 9,10-Distyrylanthracene 66

3.4.1 Solid-state emitters 66

3.4.2 Piezochromism 71

3.4.3 Fluorescent sensors and probes 73

3.4.4 Bioimaging 74

3.5 Conclusion 79

Acknowledgments 79

References 79

4 Diaminobenzene-Cored Fluorophores Exhibiting Highly Efficient Solid-State

Luminescence 82

Masaki Shimizu

4.1 Introduction 82

4.2 1,4-Bis(alkenyl)-2,5-dipiperidinobenzenes 85

4.3 1,4-Diamino-2,5-bis(arylethenyl)benzenes 88

4.4 2,5-Diaminoterephthalates 92

4.5 2,5-Bis(diarylamino)-1,4-diaroylbenzenes 94

4.6 Applications 98

4.7 Conclusion 101

Acknowledgments 101

References 102

5 Aggregation-Induced Emission in Organic Ion Pairs 104

Suzanne Fery-Forgues

5.1 Introduction 104

5.2 Historical Background 105

5.3 Preparation and Control of the Fluorophore Arrangement 106

5.3.1 Type of interactions 106

5.3.2 Preparation 106

5.3.3 Influence of the nature of the counterion on the fluorophore arrangement 107

5.3.4 Influence of stoichiometry on the AIE effect 110

5.4 AIE-Active Organic Ion Pairs in Nano- and Microparticles 110

5.4.1 Controlled preparation of nanoparticles 111

5.4.2 Nanoparticles for biomedical imaging 113

5.4.3 Preparation of nanocrystals, nanofibers, and reticulated materials 113

5.5 Applications as Fluorescent Probes and Sensors for Analytical Purposes 114

5.5.1 Detection of small electrolytes 114

5.5.2 Detection of polyelectrolytes 115

5.6 Perspectives 121

Acknowledgments 121

References 122

6 Aggregation-Induced Emission Materials: the Art of Conjugation and Rotation 125

Jing Huang, Qianqian Li, and Zhen Li

6.1 Introduction 125

6.2 Rotation and Conjugation in AIE Molecules 126

6.3 Design of Functional Materials by Tuning the Conjugation Effect and

Restricting Rotations 132

6.3.1 Some AIE molecules with blue emission through modification of the

conjugation between the construction blocks 133

6.3.2 Some sensing systems by selectively controlling rotation 140

6.3.3 Some other systems utilizing the AIE concept 143

6.4 Outlook 149

References 150

7 Red-Emitting AIE Materials 152

Xiao Yuan Shen, Anjun Qin, and Jing Zhi Sun

7.1 Introduction 152

7.2 Basic Principles of Molecular Design for Red-Emitting Materials 153

7.3 Acquirement of Red-Emitting AIE Materials by Reconstruction of Traditional

Red-Emitting Molecules 155

7.4 Preparation of Red-Emitting Materials by Introduction of Electron Donors/Acceptors

into AIE-Active Molecules 159

7.5 Outlook 161

Acknowledgments 162

References 162

8 Properties of Triarylamine Derivatives with AIE and Large Two-Photon

Absorbing Cross-Sections 165

Jianli Hua, He Tian, and Hao Zhang

8.1 Introduction 165

8.2 Design and Synthesis of Triarylamine Derivatives with AIE and 2PA 166

8.3 AIE Properties of Triarylamine Derivatives 166

8.3.1 AIE properties of diketopyrrolopyrrole (DPP)-based triarylamine derivatives 166

8.3.2 AIE properties of starburst triarylamine derivatives based on

cyano-substituted diphenylaminestyrylbenzene 169

8.3.3 AIE properties of multibranched triarylamine end-capped triazines 170

8.4 One-Photon and Two-Photon Absorption Properties of Triarylamine

Derivatives with AIE 172

8.5 Application of Triarylamine Materials with AIE and 2PA 176

8.5.1 Fluorescence switching 176

8.5.2 Organic light-emitting diodes 176

8.5.3 Fluorescence probes for hg2þ

176

8.6 Conclusion 177

References 178

9 Photoisomerization and Light-Driven Fluorescence Enhancement

of Azobenzene Derivatives 181

Mina Han and Yasuo Norikane

9.1 Introduction 181

9.2 Photoisomerization and Fluorescence of Azobenzene Derivatives 182

9.2.1 Ground-state structure of azobenzene 182

9.2.2 Reversible isomerization of azobenzene 183

9.2.3 Sterically hindered azobenzene derivatives 184

9.2.4 Fluorescence from azobenzene derivatives 186

9.3 Aggregation-Induced Emission (AIE) 187

9.4 Fluorescence from Azobenzene-Based Aggregates 189

9.4.1 Light-driven self-assembly and fluorescence enhancement 190

9.4.2 Factors affecting fluorescence enhancement of azobenzenes 191

9.4.3 Modulation of fluorescence color 192

9.4.4 Fluorescent organic films 194

9.5 Conclusion 195

References 195

10 Supramolecular Structure and Aggregation-Induced Emission 201

Hongyu Zhang and Yue Wang

10.1 Introduction 201

10.2 Hydrogen Bonding-Based Molecular Dimer and AIE 202

10.2.1 The role of hydrogen bonds in AIE 202

10.2.2 AIE and single crystal structures 204

10.2.3 Relationship between supramolecualr structures and AIE 205

10.2.4 Amplified spontaneous emission (ASE) property 206

10.3 Quinacridine Derivatives with 1D Aggregation-Induced Red Emission 206

10.3.1 Contradiction between 1D self-assembly and AIE 206

10.3.2 Design of novel QAwith AIE and 1D self-assembly 207

10.3.3 AIE behavior 208

10.3.4 Morphology transition from 0D nanostructures to 1D microwires 210

10.3.5 1D self-assembly 210

10.3.6 Crystal Structure 211

10.4 Multi-Stimuli-Responsive Fluorescence Switching of AIE/AIEE Luminogens 213

10.4.1 Mechanism of stimuli-responsive fluorescence switching 213

10.4.2 Design strategy towards stimuli-responsive AIE/AIEE molecules 214

10.4.3 AIE phenomenon in neutral and acid states 214

10.4.4 Molecular and supramolecular structures in crystal 216

10.4.5 Multi-stimuli-responsive AIE switching 216

10.4.6 Multi-stimuli-responsive fluorescence of other AIE/AIEE molecules 217

10.5 Pt Pt Interaction-Induced Emissive and Conductive 1D Crystals 218

10.5.1 AIE of organometallic complexes 218

10.5.2 Pt Pt interaction-induced luminescent crystals 219

10.5.3 1D nano-/micro aggregation and photophysical properties 219

10.5.4 Vapor-responsive emission behavior of nanowires 221

10.5.5 Pt Pt interaction-induced 1D semiconductor 221

10.6 Conclusion 222

References 223

11 Aggregation-Induced Emission in Supramolecular p-Organogels 228

Pengchong Xue and Ran Lu

11.1 Introduction 228

11.2 Organogels Based on Discotic Molecules with AIE 229

11.2.1 Triphenylbenzene-cored discotic molecules 229

11.2.2 Other discotic gelators 232

11.3 Organogels Based on Rod-Like Molecules with AIE 233

11.3.1 Styrene derivatives 233

11.3.2 Other linear molecules 236

11.4 Organogels Based on Banana-Shaped Molecules with AIE 237

11.4.1 Salicylideneaniline derivatives 237

11.4.2 Other banana-shaped gelators 240

11.5 Organogels Based on Dendritic Molecules with AIE 241

11.6 Conclusion 244

References 245

12 AIE-Active Polymers 247

Rongrong Hu, Jacky W.Y. Lam, and Ben Zhong Tang

12.1 Introduction 247

12.2 Polyolefins 248

12.3 Polyacetylenes 252

12.4 Polydiynes 253

12.5 Polyarylenes 257

12.6 Polytriazoles 263

12.7 Polysilylenevinylenes 265

12.8 Poly(Vinylene Sulfide)s 266

12.9 Other Systems 271

12.10 Conclusion 274

References 274

13 Enhanced Emission by Restriction of Molecular Rotation 278

Jin-Long Hong

13.1 Background 278

13.2 Strategy to Restrict Molecular Rotation 279

13.2.1 Introduction of bulky substituents by chemical links 280

13.2.2 Introduction of bulky groups by complexation 283

13.2.3 Hindered molecular rotation by hydrogen bonding 285

13.2.4 Hindered molecular rotation by metal or metal ion chelation 289

13.3 Characterizations of Hindered Molecular Rotations 290

13.3.1 Solution fluorescence spectroscopy 290

13.3.2 1H NMR spectroscopy 291

13.4 Conclusion 295

References 296

14 Restricted Intramolecular Rotations: a Mechanism for Aggregation-Induced

Emission 299

Junwu Chen and Ben Zhong Tang

14.1 Introduction: 2,3,4,5-Tetraphenylsilole, the Prototype Molecule

of Aggregation-Induced Emission (AIE) 299

14.2 Crystal Structures of 2,3,4,5-Tetraphenylsiloles 302

14.2.1 Twisted arrangements of phenyl groups on the silole core 302

14.2.2 Enlarged distance between silole cores: far beyond p–p interactions 303

14.3 Restricted Intramolecular Rotation (RIR) 304

14.3.1 Thickening-enhanced emission of silole solutions (viscochromism) 305

14.3.2 Piezochromism 305

14.3.3 Cooling-enhanced emission (thermochromism) 306

14.3.4 On–off fluorescence switching of silole thin films: activation

of rotations in solvent vapors (vapochromism) 308

14.3.5 Fluorescence decay dynamics 309

14.3.6 Highly emissive silole solutions: restriction of rotation by internal

structural tuning 310

14.4 Conclusion 312

Acknowledgments 312

References 312

15 Crystallization-Induced Emission Enhancement 315

Yongqiang Dong

15.1 Introduction 315

15.2 Traditional Luminogens 316

15.3 Crystallization-Induced Emission Enhancement (CIEE) 316

15.3.1 CIEE luminogens 317

15.3.2 Potential applications 322

15.4 Conclusion 325

References 326

16 Time-Resolved Spectroscopic Study of the Aggregation-Induced Emission

Mechanism 328

Bing-rong Gao, Hai-yu Wang, Qi-dai Chen, and Hong-bo Sun

16.1 Introduction 328

16.2 Time-Resolved Spectroscopy 329

16.2.1 Femtosecond time-resolved fluorescence system 329

16.2.2 Femtosecond transient absorption system 330

16.2.3 Time-correlated single-photon counting (TCSPC) system 332

16.3 AIE Molecules Without Electron Donor–Acceptor Units 332

16.3.1 Time-resolved fluorescence study of HPS 332

16.3.2 Time-resolved fluorescence study of CNDPDSB 333

16.3.3 Transient absorption study of CNDPDSB 334

16.4 AIE Molecules with Electron Donor–Acceptor Units 335

16.4.1 Steady-state properties of CNDPASDB 335

16.4.2 Time-resolved fluorescence study of CNDPASDB 337

16.4.3 Transient absorption study of CNDPASDB 342

16.4.4 Discussion 344

16.5 Conclusion 344

Acknowledgments 345

References 345

17 Theoretical Understanding of AIE Phenomena Through Computational

Chemistry 347

Qian Peng, Yingli Niu, Qunyan Wu, Xing Gao, and Zhigang Shuai

17.1 Introduction 347

17.2 Fundamental Photophysics Relating to AIE Phenomena 348

17.2.1 Absorption and emission 348

17.2.2 Luminescence quantum efficiency 349

17.3 Computational Approaches to Investigate AIE molecules 350

17.3.1 Molecular optical spectra formalisms 350

17.3.2 Molecular radiative and nonradiative rate formalisms 355

17.3.3 Computational details 357

17.4 Computational Results 360

17.4.1 Optical spectra 360

17.4.2 Excited-state decay processes 366

17.4.3 A nonadiabatic dynamic simulation 375

17.5 Summary and Outlook 379

References 380

18 Recent Theoretical Advances in Understanding the Mechanism of Aggregation-Induced

Emission for Small Organic Molecules 389

Jun-Ling Jin, Yun Geng, and Zhong-Min Su

18.1 Introduction 389

18.2 Theoretical Methods 390

18.2.1 Main photophysical processes of organic molecules 390

18.2.2 Theoretical estimation of photophysical parameters 392

18.3 Recent Theoretical Advances in Understanding the Mechanism of

Aggregation-Induced Emission 396

18.3.1 Restriction of intramolecular rotation (RIR) 396

18.3.2 Influence of molecular packing and intermolecular interactions on the

photophysical properties and fluorescence efficiencies in the solid phase 401

18.4 Prospects 403

18.4.1 Other AIE mechanisms except for the conventional RIR mechanism 403

18.4.2 Design of multifunctional materials with AIE 403

Acknowledgments 404

References 404

Index