Although the research actIvItIes of dyestuff chemists worldwide have been influenced to a great extent, in recent years, by the need to respond to a variety of environmental issues associated with the manufacture and application of synthetic dyes and pigments, a significant level of targeted research continues to be devoted to new chemistry aimed at enhancing the technical properties of dyes in commerce. This book is a presentation of various aspects of basic research conducted during the past decade but not reported in the recent review literature. The coverage herein is unique in that it emphasizes systematic approaches commonly utilized in the design and synthesis of dyes and pigments and the required intermediates. While it is well known that certain transition metals are important in the synthesis of technically viable metallized dyes for polyamide and protein fibers, these metals are demonstrated in Chapter 1 also to be effective agents in the regiospecific placement of substituents into azo compounds. The scope and limitations of this chemistry are presented. In other synthetic work, a description of the different processes employed to produce the major families of reactive dyes is presented. In Chapter 4, special attention is given to reactive dyes containing more than one reactive group, and to the more recent developments in the field. The two chapters which follow provide a review of the recent literature pertaining to novel chromophores and dyes for the D2T2 process, respectively.

More than one and a half decades have passed since the last book was published describing developments in the analytical chemistry of synthetic colorants. In the intervening period, the scope and technical capabilities of instrumentation for analysing dyes and pigments has significantly expanded. It is now possible to rapidly resolve a number of problems whose solutions were previously either unattainable or very difficult to achieve. For instance, the unambiguous assignment of all the signals in the proton NMR spectrum of a trisazo direct dye, and the confirmation of the molecular weight of involatile, and, in particular, sulphonated dyes, without derivatisation, are now routine analytical techniques in many laboratories today. In addition, it is now possible to record the NMR spectrum of a dye molecule on less than 1 mg of material, and we are no longer limited to solution spectra, since solid samples can now be routinely analysed in NMR experiments. Whilst not attempting to be all encompassing, this volume is intended to bridge the gap between what was covered in the earlier work edited by Professor Venkataraman and the developments which have since ensued in some key areas. It provides important updates in X-ray crystallography, proton NMR, IR spectroscopy and mass spectrometry, and additionally covers topics such as ESR, micro spectrophotometry and emission spectroscopy.

At the beginning of this series of volumes on Color Chemistry, the editors pointed to a number of events that have served as stimuli for techno logical advances in the field, thus preventing dyestuff manufacturing from becoming what might otherwise be viewed by now as a 'sunset industry'. The volumes which followed have provided ample evidence for our belief that the field of colour chemistry is very much alive, though arguably in need of further stimulus. For instance, a viable approach to the design of new chromophores and to the design of metal-free acid, direct, and reactive dyes having fastness properties comparable to their metallized counterparts represent the kind of breakthroughs that would help ensure the continued success of this important field. While it must be acknowledged that serendipity 'smiled' on our discipline at its inception and has repeated the favor from time to time since then, few would argue against the proposition that most of the significant advances in the technology associated with any scientific discipline result from research designed to enhance our understanding of the fundamental causes for experimental observations, many of which are pursued because they are unexpected, intriguing and intellectually stimulating. Little reflection is required for one who knows the history of the dyestuff industry to realize that this is certainly true in the colour chemistry arena, as it was basic research that led to fiber-reactive dyes, dyes for high technology, and modern synthetic organic pigments."

Although the research actIvItIes of dyestuff chemists worldwide have been influenced to a great extent, in recent years, by the need to respond to a variety of environmental issues associated with the manufacture and application of synthetic dyes and pigments, a significant level of targeted research continues to be devoted to new chemistry aimed at enhancing the technical properties of dyes in commerce. This book is a presentation of various aspects of basic research conducted during the past decade but not reported in the recent review literature. The coverage herein is unique in that it emphasizes systematic approaches commonly utilized in the design and synthesis of dyes and pigments and the required intermediates. While it is well known that certain transition metals are important in the synthesis of technically viable metallized dyes for polyamide and protein fibers, these metals are demonstrated in Chapter 1 also to be effective agents in the regiospecific placement of substituents into azo compounds. The scope and limitations of this chemistry are presented. In other synthetic work, a description of the different processes employed to produce the major families of reactive dyes is presented. In Chapter 4, special attention is given to reactive dyes containing more than one reactive group, and to the more recent developments in the field. The two chapters which follow provide a review of the recent literature pertaining to novel chromophores and dyes for the D2T2 process, respectively.

More than one and a half decades have passed since the last book was published describing developments in the analytical chemistry of synthetic colorants. In the intervening period, the scope and technical capabilities of instrumentation for analysing dyes and pigments has significantly expanded. It is now possible to rapidly resolve a number of problems whose solutions were previously either unattainable or very difficult to achieve. For instance, the unambiguous assignment of all the signals in the proton NMR spectrum of a trisazo direct dye, and the confirmation of the molecular weight of involatile, and, in particular, sulphonated dyes, without derivatisation, are now routine analytical techniques in many laboratories today. In addition, it is now possible to record the NMR spectrum of a dye molecule on less than 1 mg of material, and we are no longer limited to solution spectra, since solid samples can now be routinely analysed in NMR experiments. Whilst not attempting to be all encompassing, this volume is intended to bridge the gap between what was covered in the earlier work edited by Professor Venkataraman and the developments which have since ensued in some key areas. It provides important updates in X-ray crystallography, proton NMR, IR spectroscopy and mass spectrometry, and additionally covers topics such as ESR, micro spectrophotometry and emission spectroscopy.

This volume examines the chemistry of natural and synthetic dyes produced for non-textile markets, where much new basic research in color chemistry is now taking place.
The first group of chapters covers the design, synthesis, properties and application technology pertaining to dyes for digital printing and photography. The reader will be pleased with the breadth and depth of information presented in each case. Of particular interest is the discussion of strategies for the design of dyes in these categories, with emphasis on enhancing technical properties. In view of certain new developments, the ink-jet chapter includes results from studies pertaining to dyes for textiles.
The three chapters comprising Section II of this volume cover the broad subject of dyes for food, drug and cosmetic applications and then provide an in-depth look at dyes for biomedical applications and molecular recognition. The chapter on dyes for molecular recognition places emphasis on applications in the biological sciences, including sensory materials and artificial receptors. While the former two topics have been covered elsewhere in the past, the present chapters are unequalled in scope.
Section III provides an in-depth review of the design of laser dyes and dye-based functional materials. In the first of the two chapters, the major principles of laser operation are summarized. This is followed by a discussion of spectroscopic properties, such as activation and deactivation of absorbed light by laser dyes. Approaches to the development of new laser dyes are presented. The second chapter pertains to the synthesis of dicyanopyrazine-based multifunctional dyes. The visible and fluorescence spectra of these dyes in solution and the solid state are correlated with their three-dimensional molecular structures. Molecular stacking behavior and solid state properties of these "multifunctional" dye materials are presented.
The final group of chapters pertains to natural dyes and dyes for natural substrates. In recent years, the impression among certain consumers that "natural" is better/safer has generated much interest in the use of natural dyes rather than synthetics. This has led to a few short discussion papers in which the environmental advantages to using natural dyes have been questioned. The initial chapter in this group provides both a historical look at natural dyes and a comprehensive compilation of natural dye structures and their sources. Though natural dyes are of interest as colorants for textiles, selected ones are used primarily in food and cosmetics.
Chapter ten provides an update on the author's previous reviews of structure-color-relationships among precursors employed in the coloration of hair. Chemical constitutions characterizing hair dye structures are presented, along with a summary of available precursors and their environmental properties. Similarly, the chapter on leather dyes covers constitutions and nomenclature, in addition to providing interesting perspectives on the origin and use of leather, the dyeing of leather, and key environmental issues.
This volume is concluded with another look at colors in nature. In this case, rather than revisiting colors in plant life, an interesting chapter dealing with color in the "absence of colorants" is presented. Chapter twelve covers basic concepts of color science and illustrates how 3-D assemblies leading to a plethora of colors are handled in nature. It is our hope that this atypical "color chemistry" chapter will invoke ideas that lead to the design of useful colorants.
The chapters presented in this volume demonstrate that color chemistry still has much to offer individuals with inquiring minds who are searching for a career path. This work highlights the creativity of today's color chemists and the wide variety of interesting non-textile areas from which a career can be launched.

At the beginning of this series of volumes on Color Chemistry, the editors pointed to a number of events that have served as stimuli for techno­ logical advances in the field, thus preventing dyestuff manufacturing from becoming what might otherwise be viewed by now as a 'sunset industry'. The volumes which followed have provided ample evidence for our belief that the field of colour chemistry is very much alive, though arguably in need of further stimulus. For instance, a viable approach to the design of new chromophores and to the design of metal-free acid, direct, and reactive dyes having fastness properties comparable to their metallized counterparts represent the kind of breakthroughs that would help ensure the continued success of this important field. While it must be acknowledged that serendipity 'smiled' on our discipline at its inception and has repeated the favor from time to time since then, few would argue against the proposition that most of the significant advances in the technology associated with any scientific discipline result from research designed to enhance our understanding of the fundamental causes for experimental observations, many of which are pursued because they are unexpected, intriguing and intellectually stimulating. Little reflection is required for one who knows the history of the dyestuff industry to realize that this is certainly true in the colour chemistry arena, as it was basic research that led to fiber-reactive dyes, dyes for high technology, and modern synthetic organic pigments.