21st Century Challenges in Chemical Crystallography II: Structural Correlations and Data Interpretation

This volume summarises recent developments and highlights new techniques which will define possible future directions for small molecule X-ray crystallography. It provides an insight into how specific aspects of crystallography are developing and shows how they may interact or integrate with other areas of science.

The development of more sophisticated equipment and the massive rise in computing power has made it possible to solve the three-dimensional structure of an organic molecule within hours if not minutes. This successful trajectory has resulted in the ability to study ever more complex molecules and use smaller and smaller crystals. The structural parameters for over a million organic and organometallic compounds are now archived in the most commonly used database and this wealth of information creates a new set of problems for future generations of scientists. The volume provides some insight into how users of crystallographic structural data banks can navigatetheir way through a world where ＂big data＂ has become the norm. The coupling of crystallography to quantum chemical calculations provides detailed information about electron distributions in crystals affording a much more detailed analysis of bonding than has been possible previously. In quantum crystallography, quantum mechanical wavefunctions are used to extract information about bonding and properties from the measured X-ray structure factors. The advent of quantum crystallography has resulted in form and structure factors derived from quantum mechanics which have been used in advanced refinement and wavefunction fitting. This volume describes how quantum mechanically derived atomic form factors and structure factors are constructed to allow the improved description of the diffraction experiment. It further discusses recent developments in this field and illustrates their applications with a wide range of examples.

This volume will be of interest to chemists and crystallographers with an interest in the synthesis, characterisation and physical and catalytic properties of solid-state materials. It will also be relevant for the community of computational chemists who study chemical systems. Postgraduate students entering the field will benefit from a historical introduction to the way in which scientists have used the data derived from crystallography to develop new structural and bonding models.

Michael Mingos was born in Basra, Iraq in 1944 and was educated in England (B.Sc. in Chemistry 1965) and University of Sussex (D.Phil, 1968). He has held academic posts at QMC, Oxford (Keble College), Imperial College, St Edmund Hall (Principal,1999-2009). His theoretical research has resulted in generalisations which have greatly influenced the development and teaching of modern inorganic chemistry. Specifically the Wade-Mingos Rules which rationalise the structures of polyhedral inorganic molecules and the Green-Davies-Mingos Rules, which account for some of the nucleophilic reactions of organometallic compounds. His group has experimentally verified some of his theoretical predictions, for example an icosahedral molecule containing gold atoms -which is relevant for understanding the metal’s nano-technological possibilities. He has also contributed to the understanding of the bonding properties of nitric oxide, an important cellular signalling molecule involved in many physiological processes and pioneered the acceleration of chemical reactions using microwave energy. He was elected the Royal Society in 1992 and the European Academy of Sciences in 2017. He holds honorary doctorates from Sussex and Manchester Universities and received many prizes - the most recent was the Blaise Pascal Medal in 2017.

Paul Raithby has been Professor of Inorganic and Structural Chemistry at the University of Bath since 2000. Prior to that he spent 25 years as a Faculty member in the Department of Chemistry at the University of Cambridge. He is a Fellow of the European Academy of Sciences (EURASC) and of the Royal Society of Chemistry. He has published over 860 refereed research papers and has given over 100 lectures at national and international meetings during his career. His current research focusses on coordination chemistry, the development of the chemistry of platinum poly-ynes as sensor materials, and he has pioneered the development of time-resolved crystallographic techniques for determining the three-dimensional structures of crystalline, excited state complexes with millisecond lifetimes.