Synergy between experiment and theory

Computational studies of the properties and reactivity of transition metal complexes is an ever increasing component of many projects in inorganic and organometallic chemistry. With the advent of easy to use software and the development of accurate density functional methods, calculations on the actual experimental systems under study are no longer a daunting task. However, the complexity of the experimental systems introduces difficulties that any computational study should address. Inclusion of non-covalent dispersive interactions between the various substituents on ligands can be made at low computational cost. Even though the global influence of the solvent is now efficiently modelled with continuum approaches, the specific interactions of the solvent molecules with the system of interest are still difficult to apprehend. Nevertheless, computational strategies have now reached a level of accuracy, where, when performed in synergy with experimental work, valuable insight can be gained, leading to significant improvements.

This themed issue offers various contributions where this synergy between experience and theory has led to deeper understanding. Some of the contributions are the result of long-standing collaborations between experimental and computational chemists, where both types of studies are conducted simultaneously, nourishing each other. Some other contributions are computational studies of already published experimental work and the insight gained is aimed at improving the performance of the system.

Even though the chemical situations covered by the papers in this issue span a wide spectrum, they can be divided in three broad areas. DFT calculations of transition metal catalyzed chemical transformations form a very active field. Several papers in this issue nicely illustrate the various information that can be gained and help to delineate how a metal’s surroundings (ligands, solvent, etc.) alter the reactivity and allow for some transformations to be performed. Photophysical and magnetic properties of transition metal complexes is also a very active field where calculations play a major role. In the quest for more efficient devices, computational approaches offer the possibility to screen the influence of various substitution patterns on the optical or conducting properties. Finally, there is still room also for computational studies of the structure of transition metal complexes, as experimental means may sometimes fail to provide the basic geometrical information. In this aspect, for compounds too reactive to characterize, geometry optimization is a very powerful technique to securely locate elusive structures. In addition, molecular dynamic studies offer an alternative method to study the evolution of the coordination sphere around a transition metal cation.

The ability of computational modelling to complement and rationalize empirical data and ultimately to predict behaviour remains one of the great strengths of our discipline. I would like to thank all those authors who have contributed to this issue and whose work has contributed to make such an effective advert for the importance of computational chemistry in modern inorganic and organometallic chemistry.

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