Preface

This second edition of the Handbook of Chalcogen Chemistry appears only six years after the first edition. The need to prepare a new edition so soon has two causes: first, some important topics of the chemistry of chalcogen elements were not included in the first edition for various reasons and secondly, chalcogen chemistry continues to grow rapidly. The graph referred to in Chapter 11.3, illustrating the remarkable increase of interest in dichalcogenolene chemistry, shows that the number of papers published in the last decade has been greater than that of all papers on the same topic published up to 2000. At the same time, the chemistry of selenium and tellurium is becoming increasingly important with respect to that of sulfur in some particular fields such as semiconductors or nanoparticles and quantum dots based on polychalcogenides. In the preface to the first edition, we indicated the main factors that had led to a marked increase of interest in the chemistry of selenium and tellurium. Here, we confirm that two main factors, closely connected with each other, have contributed further to this development: (1) the considerable progress in crystallographic techniques and (2) the great variety of technological applications that have been found for many compounds of these elements. As our knowledge of the structural features of particular aggregates and of their functional mechanisms increases, new chalcogen compounds are being designed and organized in the solid state to improve their performance. The continuous demand for new compounds has stimulated the search for new sophisticated synthetic methodologies, that, particularly for the selenium and tellurium compounds, utilize the elements in their elemental state and thus avoid the use of noxious reagents.

This second edition is organized in a similar way to the first. Maintaining the periodic table as a guideline, the chapters of the first part have been substantially updated to the end of 2011. The systematic overview of chalcogen compounds in combination with the main group elements of the periodic table, from boron to the halogens, including the chalcogens themselves, offers a complete account of all the relevant chalcogen compounds. The overview is completed by the two chapters on metal chalcogenides and polychalcogenides. The second part has been extended with respect to the first edition by some important chapters in the fields of biological chemistry and material chemistry, and by a new chapter on the theoretical calculations and NMR spectroscopy. All these chapters have been included not only to improve the balance between the two parts of the handbook, but also to consider important aspects of the chemistry of the chalcogen elements that are increasing the scope for their potential applications. We can maintain that, while the first part can be considered to contain mainly aspects of fundamental research, the second part emphasizes the ambitious purpose of the handbook in pointing out the increasing role of chalcogen chemistry in satisfying the continuous need for new materials for specific applications in many fields. However, the apparent separation between the two parts is simply one of convenience since they are intimately connected; the chapters in the second part represent further developments of those in the first part. Furthermore, fundamental research often opens up new and unexpected developments, thus proving once more, if proof were necessary, that the separation between fundamental and applied research is arbitrary and irrelevant. The recent discovery that the ring‐opening polymerization of S₂N₂ to form a conducting material has potential application in forensic science (rapid imaging of latent fingerprints) represents a surprising development in chalcogen/nitrogen chemistry and underlines yet again the importance of fundamental research. Instead of an artificial separation between fundamental and applied research, we hope the Handbook clearly demonstrates the necessity of a multidisciplinary approach to tackle any research problem. As a unique example, we point out that in the explosive development of nanoscience and nanotechnology over the last few years, metal chalcogenide quantum dots have proved to be interesting materials in terms of their peculiar optical, magnetic, electronic, and catalytic properties. Their characteristics as light‐emitting diodes, or as solar cells, or in biomedicine, will stimulate synthetic chemists to develop new compounds with improved efficiency. Though not exhaustive, the book includes mainly the results from the last decade and illustrates the trends of the most striking research work. Particular attention has been paid by the authors to updating the literature as completely as possible to the end of 2011.

It is our hope that the book will serve as a reference work for years to come. The multidisciplinary approach, with chapters devoted to biological, materials, and supramolecular chemistry, renders the book an important source of information not only for chemists but also for physicists, biochemists, and other researchers who deal with chalcogen compounds. We hope the book may induce sufficient curiosity in readers to attract them towards this branch of chemistry.

We are greatly indebted to all the authors for their commitment.

Francesco Antonio Devillanova

Complesso Universitario di Monserrato, Italy

Wolf‐Walther du Mont

Technische Universität Braunschweig, Germany