A unique look at some of the hottest topics in photophysics and photochemistry today The study of molecules in excited states has exploded over the past decade, providing new insights into conformational changes in organic molecules and opening up research opportunities for scientists and professionals in chemistry, physics, biology, medicine, and materials engineering. Using conformational analysis as a unifying concept, this important new work provides readers with a cohesive and cutting-edge overview of this fascinating and challenging field. From conformational changes accompanying photoinduced electron transfer to elementary photophysical and photochemical processes in living systems, the most representative and challenging topics are carefully gleaned from the vast literature, highlighting major conceptual problems along with the relevant experimental techniques. Authoritative, detailed contributions from both experimentalists and theoreticians include coverage of: * Conformational changes in intramolecular excited state electron transfer * Conformational aspects of excited state proton transfer * The novel topic of solute-solvent friction in chemical reactions * Mechanisms and structural aspects of exciplex formations * Conformational aspects of organic photochemistry * Calculations of excited state conformational properties

Unter Zirkulardichroismus (CD) versteht man die spezifisch unterschiedliche Absorption von links- und rechtszirkular polarisiertem Licht durch bestimmte Moleküle. CD-Effekte lassen sich in Abhängigkeit von der Wellenlänge messen und spektroskopisch auswerten; sie geben beispielsweise Auskunft über die Konformation organischer Verbindungen. Dieses Buch richtet sich an den organischen Chemiker, der mit den Grundprinzipien der Stereochemie vertraut ist, und erläutert die Anwendung der CD-Spektroskopie zur Konformationsanalyse ausführlich und verständlich. (06/00)

Fluorescence reporter is the key element of any sensing or imaging technology. Its optimal choice and implementation is very important for increasing the sensitivity, precision, multiplexing power, and also the spectral, temporal, and spatial reso- tion in different methods of research and practical analysis. Therefore, design of ?uorescence reporters with advanced properties is one of the most important problems. In this volume, top experts in this ?eld provide advanced knowledge on the design and properties of ?uorescent dyes. Organic dyes were the ?rst ?uorescent materials used for analytical purposes, and we observe that they retain their leading positions against strong competition of new materials – conjugated polymers, semiconductor nanocrystals, and metal chelating complexes. Recently, molecular and cellular biology got a valuable tool of organic ?uorophores synt- sized by cell machinery and incorporated into green ?uorescent protein and its analogs. Demands of various ?uorescence techniques operating in spectral, anisotropy, and time domains require focused design of ?uorescence reporters well adapted to these techniques. Near-IR spectral range becomes more and more attractive for various applications, and new dyes emitting in this range are strongly requested. Two-photonic ?uorescence has become one of the major tools in bioimaging, and ?uorescence reporters well adapted to this technique are in urgent need. These problems cannot be solved without the knowledge of fundamental principles of dye design and of physical phenomena behind their ?uorescence response.

During Recent Years, Stereochemistry Has Undergone A Phenomenal Growth Both In Theory And Practice, With A Concomitant Increase Of Interest Among The Organic Chemists, Biological Chemists, Medicinal Chemists, And Pharmacologists. The Present Text Provides An Up-To-Date, Coherent; And Comprehensive Account Of The Subject Starting From The Fundamentals And Leading Up To The Latest Development As Far As Practicable. Emphasis Has Been Placed On Symmetry-Based Approach To Molecular Chirality, Stereochemical Terminologies (Modern Stereochemistry Is Replete, With Them), Topicity And Prostereoisomerism, Conformational Analysis, Dynamic Stereochemistry, Chiroptical Properties, And Assignment Of Absolute Configuration To Chiral Molecules.Dynamic Stereochemistry Has Been Discussed With Reference To Conformation-Reactivity Correlation, Stereoselective Syntheses, And Pericyclic Reactions. A Large Cross Section Of Organic Reactions With Stereochemical Implication Has Been Incorporated. Attempts Have Been Made To Familiarise The Readers With Modem Instrumental Techniques, Nuclear Magnetic Resonance In Particular, Used For Stereochemical Investigation. Each Chapter Is Provided With A Summary Which Highlights The Main Points Of The Text. Selective References, Mostly Of Textbooks, Monographs, Review Articles, And Significant Original Papers Have Been Given Extending Sometimes To Early 1991.The Book Is Expected To Fulfil The Long-Felt Need For A Comprehensive Text On Modern Organic Stereochemistry Which Is Conspicuously Absent Since The Publication Of Professor Eliels Book In 1962. The Text May Be Adopted At Any Stage Of The University Teaching And At The Same Time Be Useful To The Practising Organic Chemists.

From the beginnings of modern chemistry, molecular structure has been a lively area of research and speculation. For more than half a century spectroscopy and other methods have been available to characterize the structures and shapes of molecules, particularly those that are rigid. However, most molecules are at least to some degree non-rigid and this non-rigidity plays an important role in such diverse areas as biological activity, energy transfer, and chemical reactivity. In addition, the large-amplitude vibrations present in non-rigid molecules give rise to unusual low-energy vibrational level patterns which have a dramatic effect on the thermodynamic properties of these systems. Only in recent years has a coherent picture of the energetics and dynamics of the conformational changes inherent in non-rigid (and semi-rigid) molecules begun to emerge. Advances have been made in a number of different experimental areas: vibrational (infrared and Raman) spectroscopy, rotational (microwave) spectroscopy, electron diffraction, and, most recently, laser techniques probing both the ground and excited electronic states. Theoretically, the proliferation of powerful computers coupled with scientific insight has allowed both empirical and ab initio methods to increase our understanding of the forces responsible for the structures and energies of non-rigid systems. The development of theory (group theoretical methods and potential energy surfaces) to understand the unique characteristics of the spectra of these floppy molecules has also been necessary to reach our present level of understanding. The thirty chapters in this volume contributed by the key speakers at the Workshop are divided over the various areas. Both vibrational and rotational spectroscopy have been effective at determining the potential energy surfaces for non-rigid molecules, often in a complementary manner. Recent laser fluorescence work has extended these types of studies to electronic excited states. Electronic diffraction methods provide radial distribution functions from which both molecular structures and compositions of conformational mixtures can be found. Ab initio calculations have progressed substantially over the past few years, and, when carried out at a sufficiently high level, can accurately reproduce (or predict ahead of time) experimental findings. Much of the controversy of the ARW related to the question of when an ab initio is reliable. Since the computer programs are readily available, many poor calculations have been carried out. However, excellent results can be obtained from computations when properly done. A similar situation exists for experimental analyses. The complexities of non-rigid molecules are many, but major strides have been taken to understand their structures and conformational processes.