50th Anniversary of Electron Counting Paradigms for Polyhedral Molecules: Bonding in Clusters, Intermetallics and Intermetalloids (Structure and Bonding, 188)

The 50 Year Anniversary of the development of electron counting paradigms is celebrated in two volumes of Structure and Bonding. Volume 2 covers applications to metal and metalloid clusters of the transition and post-transition elements. Preface Contents Electron Counting Rules for Gold Clusters Which Are Stereochemically Non-rigid and Exhibit Skeletal Isomerism 1 Introduction 1.1 Are Clusters Stereochemically Rigid? 2 Gold Clusters [3, 4] 3 31P{1H} N.M.R. Studies in Solution and the Solid State 3.1 Solution Studies [34-42, 50, 51] 3.2 Solid State N.M.R. Studies [39, 71-74] 4 Hetero-Metallic Gold Clusters 5 A Flexible Bonding Model for Gold Clusters 5.1 Introduction 5.2 Bonding in Simple Gold Clusters [113, 120, 129, 130] 5.3 Introduction of Interstitial Atoms 5.4 Summary 6 Possible Skeletal Rearrangement Mechanisms 6.1 DSD Mechanism in Borane and Carborane Deltahedral Molecules 6.2 Orbital Symmetry Constraints for Gold Clusters 6.3 Polytopal Rearrangements in Other Metal Cluster Compounds 7 Conclusions References Electron Counting in Ligated High Nuclearity Late Transition Metal Clusters 1 Introduction 2 The Spherical Jellium Model 3 Ligated Group 11 Nanoclusters 3.1 Pseudo-Spherical Nanoclusters 3.1.1 Pseudo-Spherical Homometallic Clusters 3.1.2 Heterometallic Pseudo-Spherical Group 11-Rich Nanoclusters 3.2 Non-spherical Nanoclusters 3.2.1 Unconventional Electron Counts Stabilized by Lowering of Symmetry 3.2.2 Assemblies of Superatoms (Supermolecules) 4 Group 10 Ligated Clusters 4.1 Pseudo-Spherical Nanoclusters 4.2 Non-spherical Nanoclusters 5 Conclusion References Binary Zintl Anions Involving Group 13-15 (Semi-)Metal Atoms, and the Relationship of Their Structures to Electron Count 1 Introduction 1.1 General Remarks on Zintl Anions and Electron Counting Rules 1.2 Outline of This Chapter 2 Brief Overview of Structures and Bonding of Homoatomic Molecular Zintl Anions 2.1 Electron-Precise Zintl Anions and the 8 - N Rule 2.2 Electron-Deficient Anions and the Wade-Mingos Rules 2.3 Molecular Structures of Homoatomic Molecular Zintl Anions 3 Binary Zintl Anions of p-Block Atoms of Groups 13-15 3.1 Electron-Precise p-Block-p-Block Anions 3.1.1 P4-Type Anions 3.1.2 Nortricyclane-Type Anions 3.1.3 [SiO4]4--Type, [Be2Cl6]2--Type, CO2-Type and [CO3]2--Type Anions 3.2 Electron-Deficient p-Block-p-Block Anions Which Follow the Wade-Mingos Rules 3.3 Ternary Analogs 4 Binary Zintl Anions of p-Block and d-Block Atoms 4.1 Electron-Precise p-Block-d-Block Anions 4.1.1 Binary Cages Involving Group 13 Atoms 4.1.2 Anions Based on Cyclohexane-Type and S8-Type Units 4.1.3 Nortricyclane-Type Anions 4.1.4 SiS2 and CO2-Type Anions 4.2 Electron-Deficient p-Block-d-Block Anions 4.2.1 Tt-d-Block Anions 4.2.2 Hyp-Substituted Tt-d-Block Anions 4.2.3 Pn-d-Block Anions 4.2.4 Ternary Analogs and Special Cases 5 Summary, Outlook, and Concluding Remarks References Molecules Meet Solids: From Wade-Mingos Clusters to Intermetalloid Clusters 1 Introduction 2 The Wade-Mingos Rules: Homoatomic Deltahedra and the Isolobal Concept 3 Condensed and Discrete Intermetalloid Clusters in Intermetallic Compounds: From Wade-Mingos Rules to the Superatom Approach 4 Endohedral Intermetalloid Clusters 4.1 Building Principles of Intermetalloid Clusters in Solution 4.2 Endohedral Clusters Formed in Solution and as Building Blocks in Intermetallic Compounds 4.2.1 Filled Nine-Atomic Clusters 4.2.2 Filled Ten-Atomic Clusters 4.3 Intermetalloid Clusters Comprising Icosahedra 4.4 Intermetalloid Clusters Comprising Icosahedral Building Blocks 5 Summary References Structure and Bonding of Group 14 Clusters: Wade ́s Rules and Beyond 1 Introduction 2 A Brief Review of Wade ́s Rules and the Underlying Principles 3 Group 14 Clusters Which Conform to Wade ́s Rules 3.1 Bare Clusters [En]q- and Their Derivatives 3.2 Electronic Structure of [E9] Clusters and Its Deviation from Wade ́s Rules 4 Endohedral Clusters 4.1 Wadean Endohedral Clusters 4.2 Icosahedral Clusters That Do Not Conform to Wade ́s Rules 4.3 Competing Isomers of Endohedral Clusters 4.3.1 10-Vertex Clusters 4.3.2 12-Vertex Clusters 5 Cluster Assemblies 5.1 Clusters with Transition Metal Vertex 5.2 Metal-Bridged Cluster Assemblies 5.3 Directly Bonded Cluster Assemblies 6 Clusters Beyond Wade ́s Rules 7 Perspective References The 50 Year Anniversary of the development of electron counting paradigms for polyhedral molecules is celebrated in two volumes of Structure and Bonding. Volume 1 covers the historical development, theoretical models and applications to boranes and metalloboranes.