Polymorphism in Molecular Crystals
Polymorphism in Molecular Crystals

Author: Joel Bernstein

Publisher: Oxford University Press

Published: 2002

Total Pages: 429

ISBN-13: 0198506058

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Polymorphism - the multiplicity of structures or forms - is a term that is used in many disciplines. In chemistry it refers to the existence of more than one crystal structure for a particular chemical substance. The properties of a substance are determined by its composition and by its structure. In the last two decades, there has been a sharp rise in the interest in polymorphic systems, as an intrinsically interesting phenomenon and as an increasingly important component in the development and marketing of a variety of materials based on organic molecules (e.g. pharmaceuticals, dyes and pigments, explosives, etc.). This book summarizes and brings up to date the current knowledge and understanding of polymorphism of molecular crystals, and concentrates it in one comprehensive source. The book will be an invaluable reference for students, researchers, and professionals in the field.

Molecular Networks
Molecular Networks

Author: Mir Wais Hosseini

Publisher: Springer Science & Business Media

Published: 2009-06-29

Total Pages: 173

ISBN-13: 364201366X

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In the future, many modern materials will be increasingly based on the assembly of preformed molecular entities. Their structural characteristics and functional prop- ties will be programmed at the molecular level and their formation as a completed entity will be achieved by self-assembly processes. This in essence is a bottom-up approach and its success will require a deep understanding not only of the chemistry of intermolecular interactions and associations but also of self-assembly processes in the condensed phase. Among various interesting innovations brought about by the development of supramolecular chemistry, supramolecular synthesis is a part- ularly powerful approach for the design and generation of molecular architectures displaying both structural and functional complexity. The combination of mol- ular synthesis (which allows chemists to design and prepare extremely sophis- cated biotic and abiotic molecules through the interconnection of atoms or group of atoms by strong covalent bonds) and supramolecular synthesis (which orch- trates the association of molecules by recognition processes through the use of weak and reversible interactions) opens up endless structural and functional possibilities. Following the perceptive observation by Dunitz that "A crystal is, in a sense, the supramolecule par excellence", molecular crystals may be seen as in'nite periodic architectures resulting from the interconnection of building blocks or tectons ca- ble of self-assembling through speci'c recognising events.

Control and Prediction of Solid-State of Pharmaceuticals
Control and Prediction of Solid-State of Pharmaceuticals

Author: Rajni Miglani Bhardwaj

Publisher: Springer

Published: 2016-02-02

Total Pages: 267

ISBN-13: 3319275550

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This thesis investigates a range of experimental and computational approaches for the discovery of solid forms. Furthermore, we gain, as readers, a better understanding of the key factors underpinning solid-structure and diversity. A major part of this thesis highlights experimental work carried out on two structurally very similar compounds. Another important section involves looking at the influence of small changes in structure and substituents on solid-structure and diversity using computational tools including crystal structure prediction, PIXEL calculations, Xpac, Mercury and statistical modeling tools. In addition, the author presents a fast validated method for solid-state form screening using Raman microscopy on multi-well plates to explore the experimental crystallization space. This thesis illustrates an inexpensive, practical and accurate way to predict the crystallizability of organic compounds based on molecular structure alone, and additionally highlights the molecular factors that inhibit or promote crystallization.

Design of Organic Solids
Design of Organic Solids

Author: Edwin Weber

Publisher: Springer

Published: 2003-09-05

Total Pages: 230

ISBN-13: 3540691782

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Considering the high level of our knowledge concerning covalent bond formation in the organic chemistry of molecules, our understanding of the principles involved in organic solid design is almost in its infancy. While chemists today are able to synthesize organic molecules of very high complexity using sophisticated methods of preparation, they lack general approaches enabling them to reliably predict organic crystalline or solid structures from molecular descriptors - no matter how simple they are. On the other hand, nearly all the organic matter surrounding us is not in the single-molecule state but aggregated and condensed to form liquid or solid molecular assemblages and structural arrays giving rise to the appearances and properties of organic compounds we usually observe. Obviously, the electrical, optical or magnetic properties of solid organic materials that are important requirements for future technologies and high-tech applications, as well as the stability and solubility behavior of a medicament depend on the structure of the molecule and the intramolecular forces, but even more decisively on the intermolecular forces, i. e. the packing structure of the molecules to which a general approach is lacking. This situation concerned ]. Maddox some years ago to such a degree that he described it as "one of the continuing scandals in the physical sciences" [see (1998) Nature 335:201; see also Ball, P. (1996) Nature 381:648]. The problem of predicting organic solid and crystal structures is very dif- cult.

Organic Solid State Chemistry
Organic Solid State Chemistry

Author: Gautam R. Desiraju

Publisher: Elsevier Publishing Company

Published: 1987

Total Pages: 580

ISBN-13:

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With the growing recognition that many organic reactions may be conducted easily in the solid state and that organic solids may have unique optical/electronic properties, there has been much interest - in both academia and industry - in the subject of organic solid state chemistry. This book provides, for the first time, a coherent, unified view of the subject. It describes the packing of molecular crystals and how this packing influences chemical reactions in the solid state. It is concerned with various means of studying the chemistry and physics of molecules in constrained environments. Both experimental and theoretical approaches are discussed. Finally, it tackles the question of prediction of crystal packing, or crystal engineering'. The strength of the book lies in the twin approach adopted, namely that both conceptual and comprehensive chapters are present, in almost equal numbers.