Conformations

Among the materials found in Nature’s many diverse living organisms or produced by human industry, those made from polymers are dominant. In Nature, they are not only dominant, but they are, as well, uniquely necessary to life. Conformations: Connecting the Chemical Structures and Material Behaviors of Polymers explores how the detailed chemical structures of polymers can be characterized, how their microstructural-dependent conformational preferences can be evaluated, and how these conformational preferences can be connected to the behaviors and properties of their materials. The authors examine the connections between the microstructures of polymers and the rich variety of physical properties they evidence. Detailed polymer architectures, including the molecular bonding and geometries of backbone and side-chain groups, monomer stereo- and regiosequences, comonomer sequences, and branching, are explicitly considered in the analysis of the conformational characteristics of polymers. This valuable reference provides practicing materials engineers as well as polymer and materials science students a means of understanding the differences in behaviors and properties of materials made from chemically distinct polymers. This knowledge can assist the reader design polymers with chemical structures that lead to their desired material behaviors and properties.

The idea of conformation, or orientation of molecular shapes in space, is a fundamental concept in organic chemistry. Are you gauche enough to admit that you can’t tell a chair from a boat? This workbook, written by two award-winning instructors from the University of British Columbia, will help you identify and, more importantly, draw critical views and shapes such as the Newman projection, the anti and gauche conformations of alkanes and cyclohexane ring-flipping between one chair form and another. This workbook can be used in conjunction with any textbook.

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.

Instant Notes in Medicinal Chemistry provides concise coverage for undergraduates studying medicinal chemistry as part of a science, pharmacy or medical course. It is a truly multidisciplinary subject involving such subject specialities as organic chemistry, pharmacology, biochemistry, physiology, microbiology, toxicology, genetics and computer mod

This series presents critical reviews of the present position and future trends in modern chemical research. It contains short and concise reports on chemistry, each written by the world renowned experts. The volume is still valid and useful after five or ten years. More information, as well as the electronic version of the whole content, is available at: springerlink.com.

Molecular similarity searching is fast becoming a key tool in organic chemistry. In this book, the editor has brought together an international team of authors, each working at the forefront of this technology, providing a timely and concise overview of current research. The chapters focus principally on those methods which have reached sufficient maturity to be of immediate practical use in molecular design.

Despite remarkable progress in genome science, we are still far from a clear understanding of how genomic DNA is packaged without entanglement into a nucleus, how genes are wrapped up in chromatin, how chromatin structure is faithfully inherited from mother to daughter cells, and how the differential expression of genes is enabled in a given cell type. Exploring and answering these questions constitutes one of the next frontiers in the 21st century. We are just beginning to appreciate how Multifarious DNA structures provide additional structural and functional dimensions to chromatin organization and gene expression. DNA Conformation and Transcription is the first book that compiles the fruits of the studies that have been performed to date to solve the riddle ‘written’ in DNA conformation ("conformation code"). This book provides a comprehensive overview of the field by covering history of the field, up-to-date topics, clarifications of present day research, and future perspective of what is still to be discovered. Thus, it serves as an invaluable source of information on the "conformation code".