Review pubs.acs.org/CR Supramolecular Chirality in Self-Assembled Systems Minghua Liu,* Li Zhang, and Tianyu Wang Beijing National Laboratory for Molecular Science (BNLMS), CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China 4.3.6. Sonication 7339 4.3.7. pH Value 7340 4.4. Chiral Amplification in Supramolecular Sys- tems 7340 4.4.1. Analogue-Induced Chiral Amplification 7340 4.4.2. Chiral Amplification in Binary Systems 7343 4.4.3. Chiral Amplification to Nanoscale 7343 4.4.4. Unexpected Amplification in Racemate Assemblies 7344 4.5. Chiral Memory in Supramolecular Systems 7344 4.5.1. Helicity Memory in Noncovalently-In- duced Helical Polymers 7344 4.5.2. Chiral Memory in Aggregates Such as J and H Aggregates 7346 CONTENTS 4.5.3. Helicity Memory in Chiral Cages from Coordination Compounds 7347 1. Introduction 7305 5. Spontaneous Symmetry Breaking and Emergence 2. Basic Concepts Related to Molecular and Supra- of Supramolecular Chirality in Self-Assembled molecular Chirality 7305 Systems from Exclusively Achiral Molecules 7347 2.1. Configuration and Conformation Chirality 7306 5.1. Liquid-Crystal and Banana-Shaped Mole- 2.2. Induced Chirality 7306 cules 7348 2.3. Helicity or Helical Chirality 7307 5.2. Solution Systems, Micelles 7349 3. Characterization of Supramolecular Chirality 7308 5.3. Gel Systems 7353 3.1. Morphology Observation 7308 5.4. Air/Water Interface and LB Films 7354 3.2. Spectroscopic Methods for Characterization 5.5. Controlling Handedness of Supramolecular of Chirality 7309 Chirality 7358 3.2.1. CD Spectra of Supramolecular Systems 7309 5.5.1. Vortices and Spin Coating 7358 3.2.2. Measurement Aspects 7309 5.5.2. Circularly-Polarized Light 7361 3.2.3. CD Spectra and Interpretation 7309 5.5.3. Surface Pressure 7362 4. Supramolecular Chirality in Self-Assembled Sys- 5.6. Self-Assembly of Racemic Systems 7362 tems Containing Chiral Molecular Components 7310 6. Applications of Supramolecular Chirality 7365 4.1. Supramolecular Chirality in Assemblies of 6.1. Supramolecular Chiral Recognition and Sens- Chiral Components 7310 ing 7366 4.1.1. Amphiphiles 7310 6.2. Supramolecular Chiroptical Switches 7372 4.1.2. C -Symmetric Molecules 7313 3 6.3. Supramolecular Chiral Catalysis 7374 4.1.3. π-Conjugated Molecules 7316 6.4. Optics and Electronics Based on Supra- 4.1.4. Molecules with Multiple Chiral Centers 7324 molecular Chiral Assembly 7381 4.2. Chirality Transfer in Systems Containing 6.5. Circularly Polarized Luminescence (CPL) Chiral and Achiral Molecules 7325 Based on Chiral Supramolecular Assemblies 7381 4.2.1. Chirality Transfer through Noncovalent 6.6. Biological Applications of Supramolecular Bonds 7325 Chirality 7383 4.2.2. Chirality Transfer from Solvent to Assem- 7. Conclusions 7384 blies 7329 Author Information 7384 4.2.3. Chirality Transfer from Low Molecular Corresponding Author 7384 Weight Molecules to Macromolecules 7330 Notes 7384 4.3. Dynamic Features and Regulation of Supra- Biographies 7384 molecular Chirality 7331 4.3.1. Solvents 7332 4.3.2. Temperature 7335 4.3.3. Redox Effect Chirality 7336 Special Issue: 2015 Supramolecular Chemistry 4.3.4. Photoirradiation 7336 Received: December 8, 2014 4.3.5. Chemical Additives 7336 Published: July 20, 2015 © 2015 American Chemical Society 7304 DOI: 10.1021/cr500671p Chem. Rev. 2015, 115, 7304−7397 Chemical Reviews Review Acknowledgments 7385 biological systems and self-assembly, and many assist in References 7385 developing new drugs and materials. In this review, we present an overview of the progress in supramolecular chirality in self-assembly systems, which mainly include self-assembly in solution or in dispersion systems, 1. INTRODUCTION supramolecular gels, organized molecular films such as Langmuir − fi Chirality is a basic characteristic of living matter and nature. and Langmuir Blodgett lms, and others. Although there are During the evolution of life on our planet, nature has favored one several reviews detailing supramolecular chirality, self-assembly, 7−13 fi kind of chirality, thereby selecting the L-amino acids (with the as well as chiral nanomaterials and nanostructures, the eld exception of glycine) as the main component of proteins and has grown rapidly, and many new exciting results and enzymes and D-sugars as the main components of DNA and phenomena have emerged. Furthermore, a general view of the RNA. In addition, chirality is universal and can be observed at chirality issue through the prism of supramolecular chirality will various hierarchical levels from subatomic and molecular to be helpful in better understanding many emergent chiral supramolecular, nanoscopic, macroscopic, and galactic scales.1 phenomena. In this review, we try to provide a comprehensive Figure 1 illustrates some typical chiral substances and objects at understanding of various organized chiral systems from the these various scales. perspective of supramolecular chirality, with reference mainly to At a subatomic level, chirality is connected to parity work published after 2010. First, we will provide a general fi conservation. Therefore, only left-handed helical neutrinos are overview of the supramolecular chirality, its de nition, and found. At a molecular level, there are a huge number of chiral special features through a comparison with the molecular molecules in natural system such as amino acids, sugars, and chirality. Second, we will simply introduce the various modern terpenes, and many synthetic compounds are also chiral. techniques of characterization used in supramolecular chirality. Furthermore, there are many biological macromolecules or Third, we will show in relative detail how molecular chirality supramolecular systems with chirality, microorganisms with could be transferred or related to supramolecular chirality in self- helix-shaped viruses, and bacteria such as tobacco mosaic virus assembled systems containing chiral molecular components. and Helicobacter pylori, respectively, and macroscopic living Here, we will further show some special features of supra- systems such as snails. On a larger scale, one finds that many molecular chirality such as dynamic chirality, the principles fi plants express chiral sense, such as mountain climbing vines. On a governing the chiral ampli cation, and chiral memory. In the light-year scale, our galaxy system is also chiral. fourth part, we will discuss how achiral molecules can self- Among these various levels, chirality at a molecular and assemble into a chiral system, i.e., symmetry breaking and the supramolecular level is of vital importance since it is strongly emergence of supramolecular chirality in systems containing related to chemistry, physics, biology, materials, and nano- exclusively achiral molecules. A great challenge in the supra- science, which treat the matter in scales from atomic to molecular molecular chiral systems constructed from achiral molecules is and supramolecular.2 The concept of molecular chirality has long the control of the chirality of system. Thus, we will discuss the been recognized and provided guidance in the design of drugs manner of controlling the supramolecular chirality in systems and functional molecules, while chirality at a supramolecular level composed of achiral molecules. Finally, we will show some is currently attracting great attention due to rapid developments typical applications of supramolecular chiral systems in electro- in supramolecular chemistry and molecular self-assembly. optics, sensing, asymmetric catalysis, biological applications, Supramolecular chemistry is the chemistry beyond molecules among others. In this portion, we will focus on the uniqueness of ff or the chemistry of entities generated by intermolecular chiral supramolecular systems, how they di er from molecular noncovalent interactions.3,4 Supramolecular chemistry is chiral systems, and the new properties that emerge from strongly related to self-assembly, which has been defined as the supramolecular chirality. autonomous organization of components into patterns or Currently, with the rapid development of supramolecular structures without human intervention.5 Both molecular self- chemistry, self-assembly, and nanoscience, chirality has become an important issues, and many new chirality-related topics have assembly and supramolecular chemistry are connected by − appeared, such as chirality at a surface,14 16 chirality in a noncovalent bonds and/or certain nano/microsized architec- 17−22 23 tures. Molecular self-assembly plays an important role in coordination system, and plasmonic chirality. These biological systems, the transfer and storage of genetic topics have been discussed and reviewed but are beyond the information in nucleic acids, and the folding of proteins into scope of this review. efficient molecular machines.6 During such biological processes, supramolecular chirality, which can be simply regarded as 2. BASIC CONCEPTS RELATED TO MOLECULAR AND chirality at a supramolecular level, is the result of biological SUPRAMOLECULAR CHIRALITY molecular self-assembly. A typical example is the secondary Chiralityisusedtodescribeanobjectthatcannotbe structures of proteins, which can exhibit various conformations superimposed on its mirror image. When a molecule is not such as α-helix, β-sheet, and random coil structures with different superimposable on its mirror image, then the molecule can be supramolecular chirality. During the molecular self-assembly, termed a chiral molecule. However,