Nazario Martín, PhD, is Full Professor of Organic Chemistry at the University Complutense of Madrid and Vice-Director of the Institute of Madrid for Advanced Studies in Nanoscience, Madrid, Spain. He also served as editor-in-chief for the RSC Publications Journal of Materials Chemistry A, B and C. He has published extensively on carbon nanostructures and related subjects, and his many awards and honours include the 2012 Alexander von Humboldt award. Colin P. Nuckolls, PhD, is Sheldon and Dorothea Professor of Materials Science at Columbia University, New York, USA, where he served as Department Chair from 2008-2011. He also serves as executive editor for the ACS Publications journal NanoLetters, and his wide research experience covers molecular synthesis, reaction chemistry, and many other subjects.

• Foreword xiiiPreface xvii1 Aromaticity and Antiaromaticity in Nanographenes: An Overview 1Albert Artigas and Miquel Solà1.1 Introduction 11.2 Global and Local Aromaticity 21.3 Methods to Quantify Aromaticity 61.3.1 Energetic Descriptors of Aromaticity 71.3.2 Electronic Descriptors of Aromaticity 91.3.3 Geometric Descriptors of Aromaticity 131.3.4 Magnetic Descriptors of Aromaticity 141.4 The Analysis of Aromaticity in Nanographene Systems 201.5 Concluding Remarks 23Acknowledgments 24References 242 Covalent Patterned Functionalization of Graphene 31Tao Wei and Andreas Hirsch2.1 Introduction 312.2 Substrate-Mediated Chemical Patterning 332.3 Tip-Induced Patterned Functionalization 352.4 Lithography-assisted Molecular Engineering 372.5 Laser Writing 442.6 Conclusion 50References 513 Nanographenes by Bottom-up Approach: The Scholl Reaction 55Daniel T. Gryko, Wojciech D. Petrykowski, and Krzysztof J. Kochanowski3.1 Introduction 553.2 Planar Nanographenes 563.3 Heterocyclic Analogs of Planar Nanographenes 633.4 Nonplanar, Curved, and Twisted Nanographenes 663.5 Heterocyclic Analogs of Nonplanar Nanographenes 713.6 Surface-assisted (cyclo)Dehydration 743.7 Summary and Outlook 76Acknowledgment 77References 774 Racemization Barriers in Chiral Molecular Nanographenes 83Jesús M. Fernández-García, Patricia Izquierdo-García, Salvatore Filippone, and Nazario Martín4.1 Introduction 834.2 Structural Motifs for Chirality in Nanographenes 844.2.1 Gaussian Curvature 854.2.2 Helicenes 854.2.3 Rolling 864.2.4 Strain 874.3 Classification of Chiral Molecular NGs According to Their Isomerization Barriers 874.4 Flexible Nanographenes (4.5 Nanographenes with Spectroscopically Detectable Chirality (5–20 kcal mol −1) 894.6 Isolable Nanographenes (20–35 kcal mol −1) 904.7 Rigid Nanographenes (>35 kcal mol −1) 934.8 Enantioselective Synthesis of Rigid Molecular Nanographenes 954.9 Conclusion 98References 995 Synthesis of Helicenes 105Irena G. Stará and Ivo Starý5.1 Introduction 1055.2 Characteristics of Helicenes 1065.3 Synthetic Methodologies 1075.3.1 Photocyclodehydrogenation of 1,2-Diaryl Olefins or Arenes 1075.3.2 Oxidative Aromatic Coupling: Scholl Reaction 1115.3.3 Transition Metal-Catalyzed [2 + 2 + 2] Cycloisomerization of π-Electron Systems 1115.3.4 Diels–Alder Cycloaddition of Aromatic Vinylethers with p-Benzoquinone 1175.3.5 Transition Metal-Catalyzed Hydroarylation of Alkynes 1195.3.6 Other Synthetic Approaches 1205.4 Advanced Helicene Architectures 1235.5 Summary and Outlook 137Acknowledgment 137References 1376 Carbon Nanobelt History and Chemistry 149Hiroki Shudo, Daiki Imoto, Akiko Yagi, and Kenichiro Itami6.1 Introduction 1496.2 Synthetic Attempts to CNBs 1516.2.1 Some Synthetic Attempts to Cyclacenes 1516.2.2 CNBs Observed by Mass Spectroscopy 1526.2.3 Top-Down Approach to CNBs 1526.3 Synthesis of CNBs 1536.4 Synthesis of Related Aromatic Nanobelts 1546.5 Synthesis of Topological Aromatic Nanobelts 1576.6 Conclusion 159References 1597 Negatively Curved Nanographenes 163Ka Man Cheung and Qian Miao7.1 Introduction 1637.2 Negatively Curved Nanographenes Containing Seven-Membered Rings 1647.2.1 Incorporation of Seven-Membered Rings at an Early Stage of Synthesis 1657.2.2 Formation of Seven-Membered Rings at a Late Stage of the Synthesis 1687.3 Negatively Curved Nanographenes Containing Eight-Membered Rings 1747.3.1 Incorporation of Eight-Membered Rings at an Early Synthetic Stage 1757.3.2 Formation of Eight-Membered Rings at the Final Step of Synthesis 1797.4 Structures and Stereochemical Dynamics and Properties 1817.5 Negatively Curved Molecular Nanocarbons Beyond Nanographenes and Bottom-up Approaches to Carbon Schwarzites 1847.6 Conclusion and Outlook 186References 1888 From PAH-based Cyclophanes to Nanographenophanes 193Parinaz Salari and Graham J. Bodwell8.1 Introduction 1938.2 Synthetic Considerations 1978.3 Pentacenophanes (C22) 1998.4 Indeno[2,3-b]triphenylenophanes (C25) 2018.5 Dibenzo[c,l]chrysenophanes (C26) 2038.6 Dibenzo[f,j]picenophanes (C30) and Tetrabenz[a,c,h,j]anthracenes (c30) 2058.7 Teropyrenophanes (C36) 2078.8 A π-Extended Azacorannulenophane (C36 N) 2118.9 Hexabenzocoronenophanes (C42) 2138.10 hept-Hexabenzocoronenophanes (C43) 2178.11 Summary and Outlook 218References 2199 Bilayer and Multilayer Nanographenes: Synthesis and Properties 223Patricia Izquierdo-García, Juan Lión-Villar, Jesús M. Fernández-García, and Nazario Martín9.1 Introduction 2239.2 Van der Waals Molecular Nanographenes 2259.3 Bilayers from Fused Radicals 2309.4 Covalently Linked Bilayers 2329.5 Conclusions 238References 23910 Large π-Extended Carbon Nanorings: From Syntheses to Properties 243Jinyi Wang, Dapeng Lu, and Pingwu Du10.1 Introduction 24310.1.1 Carbon Nanorings with Inserted Six-Membered Ring-Based PAHs 24410.1.1.1 With Inserted Naphthalene(s) 24410.1.1.2 With Inserted Anthracene(s) or Phenanthrene(s) 24710.1.1.3 With Inserted Pyrene(s) or Perylene(s) 24810.1.1.4 With Inserted Other PAHs 24910.1.2 Carbon Nanorings Consisting Solely of PAHs 25210.1.2.1 Consisting Solely of Naphthalenes 25310.1.2.2 Consisting Solely of Anthracenes, Pyrenes, or Chrysenes 25410.1.2.3 Consisting Solely of Other PAHs 25510.1.3 CPP-based Oligomers and Polymers 25810.1.4 Conclusions and Outlook 261References 26211 Nanographenes with Multiple Zigzag Edges 267Ya Zou and Jishan Wu11.1 Introduction 26711.2 Peri-Acenes 26811.3 Triangular Nanographenes 27511.4 Peri-acenoacenes 27811.5 Circumarenes 27911.6 Conclusion 283References 28512 Synthesis of Graphene Nanoribbons, Nanographenes, and Fused Aromatic Networks Through the Formation of Pyrazine Rings 289Felix Hernández-Culebras and Aurelio Mateo-Alonso12.1 Introduction 28912.2 Graphene Nanoribbons and Nanographenes 28912.3 Fused Aromatic Networks 29312.4 Conclusions 300References 30013 Conjugated Nanohoops: Synthesis, Properties, and Applications 303Birgit Esser, Philipp Seitz, Andrej Weber, and Jan S. Wössner13.1 Introduction 30313.2 Synthetic Strategies to Conjugated Nanohoops 30313.2.1 Pt-, Ni-, or Au-Mediated Macrocyclizations in the Synthesis of Nanohoops 30413.2.2 Synthesis of Conjugated Nanohoops via Kinked Precursors to π-System Panels 30713.3 Properties of Conjugated Nanohoops 30913.3.1 Optoelectronic Properties 30913.3.2 Chirality 31113.3.3 Host–Guest Chemistry 31113.3.4 Solid-State Structures 31313.4 Applications of Conjugated Nanohoops 31413.4.1 Organic Electronics 31413.4.2 Bottom-up Synthesis of Carbon Nanotubes 31613.4.3 Biological Fluorophores 31713.5 Conclusions 317References 31814 Chiral Polycyclic Aromatic Compounds with Monkey Saddle Topologies 323Tobias Kirschbaum and Michael Mastalerz14.1 Introduction 32314.2 Saddle Mathematics 32714.3 Synthesis 32814.4 X-Ray Crystal Structures of Monkey Saddle PAHs 33114.5 NICS and ACID Plots 33314.6 Inversion Barriers and Chiroptical Properties 33414.7 Other Monkey Saddle PAHs and Related Systems 33714.8 Summary and Outlook 339References 34015 On-Surface Synthesis of π-Conjugated Polymers 345Nazario Martín and David Écija15.1 Introduction 34515.2 Content 34515.3 Conclusions 358References 36016 Merging Organic Chemistry with Surface Science for the Preparation of Nanographenes 363Iago Pozo, Dolores Pérez, and Diego Peña16.1 Introduction 36316.2 Scanning Probe Microscopies for the Characterization of Nanographenes Obtained by Solution-Phase Chemistry 36416.3 Combining Solution-Phase and On-Surface Chemistry for the Synthesis of Nanographenes 36616.3.1 Surface-Assisted Cyclodehydrogenation Reaction 36716.3.2 Surface-Assisted Ullmann-Type Reactions 36916.3.3 Alternative Reactions Used for the On-Surface Preparation of Nanographenes 37116.3.4 Combining On-Surface Reactions Toward the Preparation of Nanographenes 37316.4 Concluding Remarks 373References 37517 Chiral Materials from Twistacenes and Helicenes 381Si Tong Bao, Qifeng Jiang, Haoyu Jiang, Daniel Èavloviæ, and Colin Nuckolls17.1 Introduction 38117.1.1 Background 38117.1.2 The Building Block 38117.2 Twistacene-based Materials 38217.2.1 Preparation 38217.2.2 Properties 38317.2.3 Organic Photovoltaics and Photodetectors 38817.2.4 Electrochemical Storage Using hPDIs 38917.3 Helicene-Based Materials 39117.3.1 Preparation 39117.3.2 Chiral Amplification 39217.4 Future Directions 393References 39318 Nanographene Diradicals 397Fabrizia Negri and Juan Casado18.1 Introduction 39718.2 On the Origin of the Diradical State in Monocyclic Conjugated Hydrocarbons: The Case of Cyclobutadiene 40018.3 Nanographene Diradical Made from Mixtures of Quinoidal Bonding States and Nonbonding States 40318.3.1 The Zethrene Family 40418.3.2 The Bisphenalenylene Family 40618.3.3 On-Surface Diradicals 40718.3.4 Graphene Nanoribbons and Their Diradical (i.e. Polyradical Character) 40918.4 The Diradical State in All-Zig-zag Polycyclic Conjugated Hydrocarbons: On the Reversed Aromatic→Quinoidal Way to Open-Shell Nanographenes 41018.4.1 The Acenoacene Family 41118.4.2 The Oligorylene Family 41318.5 The Diradical State as a Result of Zig-zag Versus Arm-chair Structures with “Mobile” Quinoidal Rings with Quinoidal → Aromatic Transformation in the Diradical State 41518.5.1 The Peri-Acene Family 41518.5.2 The Circumacene Family 41718.5.3 The Unique Case of Rhombenes 41918.6 Conclusions 420Acknowledgments 420References 42019 Circularly Polarized Luminescence (CPL) in Nanographenes 425Carlos M. Cruz, Sandra Míguez-Lago, Daniel Salvador-Gil, and Araceli G. Campaña19.1 Introduction 42519.2 (1 × HBC)-Based Chiral Nanographenes 42819.3 (1 × HBC)-Based Heteroatom-Doped Chiral Nanographenes 43119.4 2 × HBC-Based Chiral Nanographenes 43419.5 3 × HBC-based Chiral Nanographenes 43619.6 4 × HBCs-based Chiral Nanographenes and Beyond 43819.7 Summary Table and Outlook 439Acknowledgments 445References 44520 Redox Properties of Nanographenes 449Yikun Zhu and Marina A. Petrukhina20.1 Introduction 44920.2 Planar Nanographene Fragments 45220.3 Contorted Nanographenes with Positive and Negative Curvatures 45620.3.1 Corannulene-based Nanographenes 45720.3.2 Cyclooctatetraene-based Nanographenes 46320.3.3 Bilayer Nanographene 468Acknowledgments 470References 47021 Kekulé and Non-Kekulé Nanographenes: A Magnetic Perspective 483Fupeng Wu, Muhammad Imran, Ji Ma, and Xinliang Feng21.1 Introduction 48321.2 Stable Open-Shell Kekulé NGs (S = 0) as Quantum Units 48521.3 Concealed Non-Kekulé Nanographenes (S = 0) 48621.4 Obvious Non-Kekulé Nanographenes (S > 0) 48821.4.1 Spin 1 / 2 Non-Kekulé Nanographenes (S = 1 / 2) 48921.4.2 High-Spin Non-Kekulé Nanographenes (S ≥ 1) 49221.5 Engineering of Magnetic Coupling in Non-Kekulé Nanographenes 49821.5.1 Spin 1 / 2 Dimers 49821.5.2 Triangulene (S = 1) Dimers and Trimers 50121.5.3 [3]Triangulene (S = 1) Based Spin Chains 50121.6 Summary and Outlook 504Acknowledgments 505References 505Index 511

Nazario Martín, PhD, is Full Professor of Organic Chemistry at the University Complutense of Madrid and Vice-Director of the Institute of Madrid for Advanced Studies in Nanoscience, Madrid, Spain. He also served as editor-in-chief for the RSC Publications Journal of Materials Chemistry A, B and C. He has published extensively on carbon nanostructures and related subjects, and his many awards and honours include the 2012 Alexander von Humboldt award. Colin P. Nuckolls, PhD, is Sheldon and Dorothea Professor of Materials Science at Columbia University, New York, USA, where he served as Department Chair from 2008-2011. He also serves as executive editor for the ACS Publications journal NanoLetters, and his wide research experience covers molecular synthesis, reaction chemistry, and many other subjects.

• Foreword xiiiPreface xvii1 Aromaticity and Antiaromaticity in Nanographenes: An Overview 1Albert Artigas and Miquel Solà1.1 Introduction 11.2 Global and Local Aromaticity 21.3 Methods to Quantify Aromaticity 61.3.1 Energetic Descriptors of Aromaticity 71.3.2 Electronic Descriptors of Aromaticity 91.3.3 Geometric Descriptors of Aromaticity 131.3.4 Magnetic Descriptors of Aromaticity 141.4 The Analysis of Aromaticity in Nanographene Systems 201.5 Concluding Remarks 23Acknowledgments 24References 242 Covalent Patterned Functionalization of Graphene 31Tao Wei and Andreas Hirsch2.1 Introduction 312.2 Substrate-Mediated Chemical Patterning 332.3 Tip-Induced Patterned Functionalization 352.4 Lithography-assisted Molecular Engineering 372.5 Laser Writing 442.6 Conclusion 50References 513 Nanographenes by Bottom-up Approach: The Scholl Reaction 55Daniel T. Gryko, Wojciech D. Petrykowski, and Krzysztof J. Kochanowski3.1 Introduction 553.2 Planar Nanographenes 563.3 Heterocyclic Analogs of Planar Nanographenes 633.4 Nonplanar, Curved, and Twisted Nanographenes 663.5 Heterocyclic Analogs of Nonplanar Nanographenes 713.6 Surface-assisted (cyclo)Dehydration 743.7 Summary and Outlook 76Acknowledgment 77References 774 Racemization Barriers in Chiral Molecular Nanographenes 83Jesús M. Fernández-García, Patricia Izquierdo-García, Salvatore Filippone, and Nazario Martín4.1 Introduction 834.2 Structural Motifs for Chirality in Nanographenes 844.2.1 Gaussian Curvature 854.2.2 Helicenes 854.2.3 Rolling 864.2.4 Strain 874.3 Classification of Chiral Molecular NGs According to Their Isomerization Barriers 874.4 Flexible Nanographenes (4.5 Nanographenes with Spectroscopically Detectable Chirality (5–20 kcal mol −1) 894.6 Isolable Nanographenes (20–35 kcal mol −1) 904.7 Rigid Nanographenes (>35 kcal mol −1) 934.8 Enantioselective Synthesis of Rigid Molecular Nanographenes 954.9 Conclusion 98References 995 Synthesis of Helicenes 105Irena G. Stará and Ivo Starý5.1 Introduction 1055.2 Characteristics of Helicenes 1065.3 Synthetic Methodologies 1075.3.1 Photocyclodehydrogenation of 1,2-Diaryl Olefins or Arenes 1075.3.2 Oxidative Aromatic Coupling: Scholl Reaction 1115.3.3 Transition Metal-Catalyzed [2 + 2 + 2] Cycloisomerization of π-Electron Systems 1115.3.4 Diels–Alder Cycloaddition of Aromatic Vinylethers with p-Benzoquinone 1175.3.5 Transition Metal-Catalyzed Hydroarylation of Alkynes 1195.3.6 Other Synthetic Approaches 1205.4 Advanced Helicene Architectures 1235.5 Summary and Outlook 137Acknowledgment 137References 1376 Carbon Nanobelt History and Chemistry 149Hiroki Shudo, Daiki Imoto, Akiko Yagi, and Kenichiro Itami6.1 Introduction 1496.2 Synthetic Attempts to CNBs 1516.2.1 Some Synthetic Attempts to Cyclacenes 1516.2.2 CNBs Observed by Mass Spectroscopy 1526.2.3 Top-Down Approach to CNBs 1526.3 Synthesis of CNBs 1536.4 Synthesis of Related Aromatic Nanobelts 1546.5 Synthesis of Topological Aromatic Nanobelts 1576.6 Conclusion 159References 1597 Negatively Curved Nanographenes 163Ka Man Cheung and Qian Miao7.1 Introduction 1637.2 Negatively Curved Nanographenes Containing Seven-Membered Rings 1647.2.1 Incorporation of Seven-Membered Rings at an Early Stage of Synthesis 1657.2.2 Formation of Seven-Membered Rings at a Late Stage of the Synthesis 1687.3 Negatively Curved Nanographenes Containing Eight-Membered Rings 1747.3.1 Incorporation of Eight-Membered Rings at an Early Synthetic Stage 1757.3.2 Formation of Eight-Membered Rings at the Final Step of Synthesis 1797.4 Structures and Stereochemical Dynamics and Properties 1817.5 Negatively Curved Molecular Nanocarbons Beyond Nanographenes and Bottom-up Approaches to Carbon Schwarzites 1847.6 Conclusion and Outlook 186References 1888 From PAH-based Cyclophanes to Nanographenophanes 193Parinaz Salari and Graham J. Bodwell8.1 Introduction 1938.2 Synthetic Considerations 1978.3 Pentacenophanes (C22) 1998.4 Indeno[2,3-b]triphenylenophanes (C25) 2018.5 Dibenzo[c,l]chrysenophanes (C26) 2038.6 Dibenzo[f,j]picenophanes (C30) and Tetrabenz[a,c,h,j]anthracenes (c30) 2058.7 Teropyrenophanes (C36) 2078.8 A π-Extended Azacorannulenophane (C36 N) 2118.9 Hexabenzocoronenophanes (C42) 2138.10 hept-Hexabenzocoronenophanes (C43) 2178.11 Summary and Outlook 218References 2199 Bilayer and Multilayer Nanographenes: Synthesis and Properties 223Patricia Izquierdo-García, Juan Lión-Villar, Jesús M. Fernández-García, and Nazario Martín9.1 Introduction 2239.2 Van der Waals Molecular Nanographenes 2259.3 Bilayers from Fused Radicals 2309.4 Covalently Linked Bilayers 2329.5 Conclusions 238References 23910 Large π-Extended Carbon Nanorings: From Syntheses to Properties 243Jinyi Wang, Dapeng Lu, and Pingwu Du10.1 Introduction 24310.1.1 Carbon Nanorings with Inserted Six-Membered Ring-Based PAHs 24410.1.1.1 With Inserted Naphthalene(s) 24410.1.1.2 With Inserted Anthracene(s) or Phenanthrene(s) 24710.1.1.3 With Inserted Pyrene(s) or Perylene(s) 24810.1.1.4 With Inserted Other PAHs 24910.1.2 Carbon Nanorings Consisting Solely of PAHs 25210.1.2.1 Consisting Solely of Naphthalenes 25310.1.2.2 Consisting Solely of Anthracenes, Pyrenes, or Chrysenes 25410.1.2.3 Consisting Solely of Other PAHs 25510.1.3 CPP-based Oligomers and Polymers 25810.1.4 Conclusions and Outlook 261References 26211 Nanographenes with Multiple Zigzag Edges 267Ya Zou and Jishan Wu11.1 Introduction 26711.2 Peri-Acenes 26811.3 Triangular Nanographenes 27511.4 Peri-acenoacenes 27811.5 Circumarenes 27911.6 Conclusion 283References 28512 Synthesis of Graphene Nanoribbons, Nanographenes, and Fused Aromatic Networks Through the Formation of Pyrazine Rings 289Felix Hernández-Culebras and Aurelio Mateo-Alonso12.1 Introduction 28912.2 Graphene Nanoribbons and Nanographenes 28912.3 Fused Aromatic Networks 29312.4 Conclusions 300References 30013 Conjugated Nanohoops: Synthesis, Properties, and Applications 303Birgit Esser, Philipp Seitz, Andrej Weber, and Jan S. Wössner13.1 Introduction 30313.2 Synthetic Strategies to Conjugated Nanohoops 30313.2.1 Pt-, Ni-, or Au-Mediated Macrocyclizations in the Synthesis of Nanohoops 30413.2.2 Synthesis of Conjugated Nanohoops via Kinked Precursors to π-System Panels 30713.3 Properties of Conjugated Nanohoops 30913.3.1 Optoelectronic Properties 30913.3.2 Chirality 31113.3.3 Host–Guest Chemistry 31113.3.4 Solid-State Structures 31313.4 Applications of Conjugated Nanohoops 31413.4.1 Organic Electronics 31413.4.2 Bottom-up Synthesis of Carbon Nanotubes 31613.4.3 Biological Fluorophores 31713.5 Conclusions 317References 31814 Chiral Polycyclic Aromatic Compounds with Monkey Saddle Topologies 323Tobias Kirschbaum and Michael Mastalerz14.1 Introduction 32314.2 Saddle Mathematics 32714.3 Synthesis 32814.4 X-Ray Crystal Structures of Monkey Saddle PAHs 33114.5 NICS and ACID Plots 33314.6 Inversion Barriers and Chiroptical Properties 33414.7 Other Monkey Saddle PAHs and Related Systems 33714.8 Summary and Outlook 339References 34015 On-Surface Synthesis of π-Conjugated Polymers 345Nazario Martín and David Écija15.1 Introduction 34515.2 Content 34515.3 Conclusions 358References 36016 Merging Organic Chemistry with Surface Science for the Preparation of Nanographenes 363Iago Pozo, Dolores Pérez, and Diego Peña16.1 Introduction 36316.2 Scanning Probe Microscopies for the Characterization of Nanographenes Obtained by Solution-Phase Chemistry 36416.3 Combining Solution-Phase and On-Surface Chemistry for the Synthesis of Nanographenes 36616.3.1 Surface-Assisted Cyclodehydrogenation Reaction 36716.3.2 Surface-Assisted Ullmann-Type Reactions 36916.3.3 Alternative Reactions Used for the On-Surface Preparation of Nanographenes 37116.3.4 Combining On-Surface Reactions Toward the Preparation of Nanographenes 37316.4 Concluding Remarks 373References 37517 Chiral Materials from Twistacenes and Helicenes 381Si Tong Bao, Qifeng Jiang, Haoyu Jiang, Daniel Èavloviæ, and Colin Nuckolls17.1 Introduction 38117.1.1 Background 38117.1.2 The Building Block 38117.2 Twistacene-based Materials 38217.2.1 Preparation 38217.2.2 Properties 38317.2.3 Organic Photovoltaics and Photodetectors 38817.2.4 Electrochemical Storage Using hPDIs 38917.3 Helicene-Based Materials 39117.3.1 Preparation 39117.3.2 Chiral Amplification 39217.4 Future Directions 393References 39318 Nanographene Diradicals 397Fabrizia Negri and Juan Casado18.1 Introduction 39718.2 On the Origin of the Diradical State in Monocyclic Conjugated Hydrocarbons: The Case of Cyclobutadiene 40018.3 Nanographene Diradical Made from Mixtures of Quinoidal Bonding States and Nonbonding States 40318.3.1 The Zethrene Family 40418.3.2 The Bisphenalenylene Family 40618.3.3 On-Surface Diradicals 40718.3.4 Graphene Nanoribbons and Their Diradical (i.e. Polyradical Character) 40918.4 The Diradical State in All-Zig-zag Polycyclic Conjugated Hydrocarbons: On the Reversed Aromatic→Quinoidal Way to Open-Shell Nanographenes 41018.4.1 The Acenoacene Family 41118.4.2 The Oligorylene Family 41318.5 The Diradical State as a Result of Zig-zag Versus Arm-chair Structures with “Mobile” Quinoidal Rings with Quinoidal → Aromatic Transformation in the Diradical State 41518.5.1 The Peri-Acene Family 41518.5.2 The Circumacene Family 41718.5.3 The Unique Case of Rhombenes 41918.6 Conclusions 420Acknowledgments 420References 42019 Circularly Polarized Luminescence (CPL) in Nanographenes 425Carlos M. Cruz, Sandra Míguez-Lago, Daniel Salvador-Gil, and Araceli G. Campaña19.1 Introduction 42519.2 (1 × HBC)-Based Chiral Nanographenes 42819.3 (1 × HBC)-Based Heteroatom-Doped Chiral Nanographenes 43119.4 2 × HBC-Based Chiral Nanographenes 43419.5 3 × HBC-based Chiral Nanographenes 43619.6 4 × HBCs-based Chiral Nanographenes and Beyond 43819.7 Summary Table and Outlook 439Acknowledgments 445References 44520 Redox Properties of Nanographenes 449Yikun Zhu and Marina A. Petrukhina20.1 Introduction 44920.2 Planar Nanographene Fragments 45220.3 Contorted Nanographenes with Positive and Negative Curvatures 45620.3.1 Corannulene-based Nanographenes 45720.3.2 Cyclooctatetraene-based Nanographenes 46320.3.3 Bilayer Nanographene 468Acknowledgments 470References 47021 Kekulé and Non-Kekulé Nanographenes: A Magnetic Perspective 483Fupeng Wu, Muhammad Imran, Ji Ma, and Xinliang Feng21.1 Introduction 48321.2 Stable Open-Shell Kekulé NGs (S = 0) as Quantum Units 48521.3 Concealed Non-Kekulé Nanographenes (S = 0) 48621.4 Obvious Non-Kekulé Nanographenes (S > 0) 48821.4.1 Spin 1 / 2 Non-Kekulé Nanographenes (S = 1 / 2) 48921.4.2 High-Spin Non-Kekulé Nanographenes (S ≥ 1) 49221.5 Engineering of Magnetic Coupling in Non-Kekulé Nanographenes 49821.5.1 Spin 1 / 2 Dimers 49821.5.2 Triangulene (S = 1) Dimers and Trimers 50121.5.3 [3]Triangulene (S = 1) Based Spin Chains 50121.6 Summary and Outlook 504Acknowledgments 505References 505Index 511

Nazario Martín, PhD, is Full Professor of Organic Chemistry at the University Complutense of Madrid and Vice-Director of the Institute of Madrid for Advanced Studies in Nanoscience, Madrid, Spain. He also served as editor-in-chief for the RSC Publications Journal of Materials Chemistry A, B and C. He has published extensively on carbon nanostructures and related subjects, and his many awards and honours include the 2012 Alexander von Humboldt award. Colin P. Nuckolls, PhD, is Sheldon and Dorothea Professor of Materials Science at Columbia University, New York, USA, where he served as Department Chair from 2008-2011. He also serves as executive editor for the ACS Publications journal NanoLetters, and his wide research experience covers molecular synthesis, reaction chemistry, and many other subjects.

• Foreword xiiiPreface xvii1 Aromaticity and Antiaromaticity in Nanographenes: An Overview 1Albert Artigas and Miquel Solà1.1 Introduction 11.2 Global and Local Aromaticity 21.3 Methods to Quantify Aromaticity 61.3.1 Energetic Descriptors of Aromaticity 71.3.2 Electronic Descriptors of Aromaticity 91.3.3 Geometric Descriptors of Aromaticity 131.3.4 Magnetic Descriptors of Aromaticity 141.4 The Analysis of Aromaticity in Nanographene Systems 201.5 Concluding Remarks 23Acknowledgments 24References 242 Covalent Patterned Functionalization of Graphene 31Tao Wei and Andreas Hirsch2.1 Introduction 312.2 Substrate-Mediated Chemical Patterning 332.3 Tip-Induced Patterned Functionalization 352.4 Lithography-assisted Molecular Engineering 372.5 Laser Writing 442.6 Conclusion 50References 513 Nanographenes by Bottom-up Approach: The Scholl Reaction 55Daniel T. Gryko, Wojciech D. Petrykowski, and Krzysztof J. Kochanowski3.1 Introduction 553.2 Planar Nanographenes 563.3 Heterocyclic Analogs of Planar Nanographenes 633.4 Nonplanar, Curved, and Twisted Nanographenes 663.5 Heterocyclic Analogs of Nonplanar Nanographenes 713.6 Surface-assisted (cyclo)Dehydration 743.7 Summary and Outlook 76Acknowledgment 77References 774 Racemization Barriers in Chiral Molecular Nanographenes 83Jesús M. Fernández-García, Patricia Izquierdo-García, Salvatore Filippone, and Nazario Martín4.1 Introduction 834.2 Structural Motifs for Chirality in Nanographenes 844.2.1 Gaussian Curvature 854.2.2 Helicenes 854.2.3 Rolling 864.2.4 Strain 874.3 Classification of Chiral Molecular NGs According to Their Isomerization Barriers 874.4 Flexible Nanographenes (4.5 Nanographenes with Spectroscopically Detectable Chirality (5–20 kcal mol −1) 894.6 Isolable Nanographenes (20–35 kcal mol −1) 904.7 Rigid Nanographenes (>35 kcal mol −1) 934.8 Enantioselective Synthesis of Rigid Molecular Nanographenes 954.9 Conclusion 98References 995 Synthesis of Helicenes 105Irena G. Stará and Ivo Starý5.1 Introduction 1055.2 Characteristics of Helicenes 1065.3 Synthetic Methodologies 1075.3.1 Photocyclodehydrogenation of 1,2-Diaryl Olefins or Arenes 1075.3.2 Oxidative Aromatic Coupling: Scholl Reaction 1115.3.3 Transition Metal-Catalyzed [2 + 2 + 2] Cycloisomerization of π-Electron Systems 1115.3.4 Diels–Alder Cycloaddition of Aromatic Vinylethers with p-Benzoquinone 1175.3.5 Transition Metal-Catalyzed Hydroarylation of Alkynes 1195.3.6 Other Synthetic Approaches 1205.4 Advanced Helicene Architectures 1235.5 Summary and Outlook 137Acknowledgment 137References 1376 Carbon Nanobelt History and Chemistry 149Hiroki Shudo, Daiki Imoto, Akiko Yagi, and Kenichiro Itami6.1 Introduction 1496.2 Synthetic Attempts to CNBs 1516.2.1 Some Synthetic Attempts to Cyclacenes 1516.2.2 CNBs Observed by Mass Spectroscopy 1526.2.3 Top-Down Approach to CNBs 1526.3 Synthesis of CNBs 1536.4 Synthesis of Related Aromatic Nanobelts 1546.5 Synthesis of Topological Aromatic Nanobelts 1576.6 Conclusion 159References 1597 Negatively Curved Nanographenes 163Ka Man Cheung and Qian Miao7.1 Introduction 1637.2 Negatively Curved Nanographenes Containing Seven-Membered Rings 1647.2.1 Incorporation of Seven-Membered Rings at an Early Stage of Synthesis 1657.2.2 Formation of Seven-Membered Rings at a Late Stage of the Synthesis 1687.3 Negatively Curved Nanographenes Containing Eight-Membered Rings 1747.3.1 Incorporation of Eight-Membered Rings at an Early Synthetic Stage 1757.3.2 Formation of Eight-Membered Rings at the Final Step of Synthesis 1797.4 Structures and Stereochemical Dynamics and Properties 1817.5 Negatively Curved Molecular Nanocarbons Beyond Nanographenes and Bottom-up Approaches to Carbon Schwarzites 1847.6 Conclusion and Outlook 186References 1888 From PAH-based Cyclophanes to Nanographenophanes 193Parinaz Salari and Graham J. Bodwell8.1 Introduction 1938.2 Synthetic Considerations 1978.3 Pentacenophanes (C22) 1998.4 Indeno[2,3-b]triphenylenophanes (C25) 2018.5 Dibenzo[c,l]chrysenophanes (C26) 2038.6 Dibenzo[f,j]picenophanes (C30) and Tetrabenz[a,c,h,j]anthracenes (c30) 2058.7 Teropyrenophanes (C36) 2078.8 A π-Extended Azacorannulenophane (C36 N) 2118.9 Hexabenzocoronenophanes (C42) 2138.10 hept-Hexabenzocoronenophanes (C43) 2178.11 Summary and Outlook 218References 2199 Bilayer and Multilayer Nanographenes: Synthesis and Properties 223Patricia Izquierdo-García, Juan Lión-Villar, Jesús M. Fernández-García, and Nazario Martín9.1 Introduction 2239.2 Van der Waals Molecular Nanographenes 2259.3 Bilayers from Fused Radicals 2309.4 Covalently Linked Bilayers 2329.5 Conclusions 238References 23910 Large π-Extended Carbon Nanorings: From Syntheses to Properties 243Jinyi Wang, Dapeng Lu, and Pingwu Du10.1 Introduction 24310.1.1 Carbon Nanorings with Inserted Six-Membered Ring-Based PAHs 24410.1.1.1 With Inserted Naphthalene(s) 24410.1.1.2 With Inserted Anthracene(s) or Phenanthrene(s) 24710.1.1.3 With Inserted Pyrene(s) or Perylene(s) 24810.1.1.4 With Inserted Other PAHs 24910.1.2 Carbon Nanorings Consisting Solely of PAHs 25210.1.2.1 Consisting Solely of Naphthalenes 25310.1.2.2 Consisting Solely of Anthracenes, Pyrenes, or Chrysenes 25410.1.2.3 Consisting Solely of Other PAHs 25510.1.3 CPP-based Oligomers and Polymers 25810.1.4 Conclusions and Outlook 261References 26211 Nanographenes with Multiple Zigzag Edges 267Ya Zou and Jishan Wu11.1 Introduction 26711.2 Peri-Acenes 26811.3 Triangular Nanographenes 27511.4 Peri-acenoacenes 27811.5 Circumarenes 27911.6 Conclusion 283References 28512 Synthesis of Graphene Nanoribbons, Nanographenes, and Fused Aromatic Networks Through the Formation of Pyrazine Rings 289Felix Hernández-Culebras and Aurelio Mateo-Alonso12.1 Introduction 28912.2 Graphene Nanoribbons and Nanographenes 28912.3 Fused Aromatic Networks 29312.4 Conclusions 300References 30013 Conjugated Nanohoops: Synthesis, Properties, and Applications 303Birgit Esser, Philipp Seitz, Andrej Weber, and Jan S. Wössner13.1 Introduction 30313.2 Synthetic Strategies to Conjugated Nanohoops 30313.2.1 Pt-, Ni-, or Au-Mediated Macrocyclizations in the Synthesis of Nanohoops 30413.2.2 Synthesis of Conjugated Nanohoops via Kinked Precursors to π-System Panels 30713.3 Properties of Conjugated Nanohoops 30913.3.1 Optoelectronic Properties 30913.3.2 Chirality 31113.3.3 Host–Guest Chemistry 31113.3.4 Solid-State Structures 31313.4 Applications of Conjugated Nanohoops 31413.4.1 Organic Electronics 31413.4.2 Bottom-up Synthesis of Carbon Nanotubes 31613.4.3 Biological Fluorophores 31713.5 Conclusions 317References 31814 Chiral Polycyclic Aromatic Compounds with Monkey Saddle Topologies 323Tobias Kirschbaum and Michael Mastalerz14.1 Introduction 32314.2 Saddle Mathematics 32714.3 Synthesis 32814.4 X-Ray Crystal Structures of Monkey Saddle PAHs 33114.5 NICS and ACID Plots 33314.6 Inversion Barriers and Chiroptical Properties 33414.7 Other Monkey Saddle PAHs and Related Systems 33714.8 Summary and Outlook 339References 34015 On-Surface Synthesis of π-Conjugated Polymers 345Nazario Martín and David Écija15.1 Introduction 34515.2 Content 34515.3 Conclusions 358References 36016 Merging Organic Chemistry with Surface Science for the Preparation of Nanographenes 363Iago Pozo, Dolores Pérez, and Diego Peña16.1 Introduction 36316.2 Scanning Probe Microscopies for the Characterization of Nanographenes Obtained by Solution-Phase Chemistry 36416.3 Combining Solution-Phase and On-Surface Chemistry for the Synthesis of Nanographenes 36616.3.1 Surface-Assisted Cyclodehydrogenation Reaction 36716.3.2 Surface-Assisted Ullmann-Type Reactions 36916.3.3 Alternative Reactions Used for the On-Surface Preparation of Nanographenes 37116.3.4 Combining On-Surface Reactions Toward the Preparation of Nanographenes 37316.4 Concluding Remarks 373References 37517 Chiral Materials from Twistacenes and Helicenes 381Si Tong Bao, Qifeng Jiang, Haoyu Jiang, Daniel Èavloviæ, and Colin Nuckolls17.1 Introduction 38117.1.1 Background 38117.1.2 The Building Block 38117.2 Twistacene-based Materials 38217.2.1 Preparation 38217.2.2 Properties 38317.2.3 Organic Photovoltaics and Photodetectors 38817.2.4 Electrochemical Storage Using hPDIs 38917.3 Helicene-Based Materials 39117.3.1 Preparation 39117.3.2 Chiral Amplification 39217.4 Future Directions 393References 39318 Nanographene Diradicals 397Fabrizia Negri and Juan Casado18.1 Introduction 39718.2 On the Origin of the Diradical State in Monocyclic Conjugated Hydrocarbons: The Case of Cyclobutadiene 40018.3 Nanographene Diradical Made from Mixtures of Quinoidal Bonding States and Nonbonding States 40318.3.1 The Zethrene Family 40418.3.2 The Bisphenalenylene Family 40618.3.3 On-Surface Diradicals 40718.3.4 Graphene Nanoribbons and Their Diradical (i.e. Polyradical Character) 40918.4 The Diradical State in All-Zig-zag Polycyclic Conjugated Hydrocarbons: On the Reversed Aromatic→Quinoidal Way to Open-Shell Nanographenes 41018.4.1 The Acenoacene Family 41118.4.2 The Oligorylene Family 41318.5 The Diradical State as a Result of Zig-zag Versus Arm-chair Structures with “Mobile” Quinoidal Rings with Quinoidal → Aromatic Transformation in the Diradical State 41518.5.1 The Peri-Acene Family 41518.5.2 The Circumacene Family 41718.5.3 The Unique Case of Rhombenes 41918.6 Conclusions 420Acknowledgments 420References 42019 Circularly Polarized Luminescence (CPL) in Nanographenes 425Carlos M. Cruz, Sandra Míguez-Lago, Daniel Salvador-Gil, and Araceli G. Campaña19.1 Introduction 42519.2 (1 × HBC)-Based Chiral Nanographenes 42819.3 (1 × HBC)-Based Heteroatom-Doped Chiral Nanographenes 43119.4 2 × HBC-Based Chiral Nanographenes 43419.5 3 × HBC-based Chiral Nanographenes 43619.6 4 × HBCs-based Chiral Nanographenes and Beyond 43819.7 Summary Table and Outlook 439Acknowledgments 445References 44520 Redox Properties of Nanographenes 449Yikun Zhu and Marina A. Petrukhina20.1 Introduction 44920.2 Planar Nanographene Fragments 45220.3 Contorted Nanographenes with Positive and Negative Curvatures 45620.3.1 Corannulene-based Nanographenes 45720.3.2 Cyclooctatetraene-based Nanographenes 46320.3.3 Bilayer Nanographene 468Acknowledgments 470References 47021 Kekulé and Non-Kekulé Nanographenes: A Magnetic Perspective 483Fupeng Wu, Muhammad Imran, Ji Ma, and Xinliang Feng21.1 Introduction 48321.2 Stable Open-Shell Kekulé NGs (S = 0) as Quantum Units 48521.3 Concealed Non-Kekulé Nanographenes (S = 0) 48621.4 Obvious Non-Kekulé Nanographenes (S > 0) 48821.4.1 Spin 1 / 2 Non-Kekulé Nanographenes (S = 1 / 2) 48921.4.2 High-Spin Non-Kekulé Nanographenes (S ≥ 1) 49221.5 Engineering of Magnetic Coupling in Non-Kekulé Nanographenes 49821.5.1 Spin 1 / 2 Dimers 49821.5.2 Triangulene (S = 1) Dimers and Trimers 50121.5.3 [3]Triangulene (S = 1) Based Spin Chains 50121.6 Summary and Outlook 504Acknowledgments 505References 505Index 511