Computational organometallic chemistry

Chemists have increasingly used computational chemistry to study aspects of organometallic chemistry. Although Chapter 2 and subsequent chapters make good use of qualitative molecular orbital theory, the ready availability of easy-to-use computational chemistry software and the powerful capability of modem desktop computers allow chemists to effectively model complex systems to obtain minimum energy geometry of molecules, determine transition state energies, and predict the course of chemical reactions, particularly if two or more isomeric products could form. Researchers have modeled entire catalytic cycles, which 

Different MM methods are available to chemists and abbreviations reminiscent of the approach used to develop them are associated with each of them. Some of the methods suitable for use in organometallic chemistry are known as augmented MM2 and MM3, as well as UFF, which stand for molecular mechanics version 2 or 3 and tmiversal/orce /ield, respectively. The force fields for each of these methods are parameterized for the transition metals as well as the ligands attached. 

The MO approach to molecular energy and other properties is fundamentally different than that of MM. In MM we assume that nuclei move and electrons are essentially stationary, that is, they are not explicitly considered in the force field calculations. Most MO approaches use the Bom-Oppenheimer approximation, which considers nuclei relatively stationary compared with fast-moving electrons. Thus, the MO approach must somehow address electron motion and energy. Because the motion of electrons is governed by the Heisenberg Uncertainty Principle, quantum mechanical rather than classical physical calculations must be used. 

An MO calculation is a many-body problem that cannot be solved exactly. Thus, various levels of approximation must be applied to determine MO energy levels and contours, molecular energy, and other characteristics of molecules. We will consider briefly these levels of approximation, which manifest themselves as MO methods that have acronyms associated with them, and also discuss how these methods can be applied to organometallic chemistry. 

Before the ready availability of high-speed computers, theoreticians realized that for them to perform MO calculations on anything but the very smallest molecules, they would need to reduce the mathematical intensity of the computation. They did this not only by making approximations that greatly reduced the size of the basis set (typically only the outer atomic orbitals are included in the calculation), but they also ignored the interaction of some of these basis set orbitals, which often turned out to be small and thus could be neglected. To make the computation yield results that were close to experimental values, numerical parameters were added that were derived empirically by experiment, hence the term semi-empirical.  

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Computational Organometallic Chemistry, Cundari, T., Ed., Marcel Dekker New York, 2001. 

M. Diedenhofen, T. Wagener, and G. Frenking, Computational Organometallic Chemistry Marcell Dekker, New York, in print. 

Maseras F (2001) In Cundari TR (ed) Computational organometallic chemistry. Marcel Dekker, New York... 

Yates, B. Computational organometallic chemistry. Chem. Austr. 2001, 68,16-18. 

Cundari, Thomas R. Computational Organometallic Chemistry. New York Marcel Dckkcr, 2001. 

Computational Organometallic Chemistry, T. R. Cundari, Ed., Dekker New York, 2001. W. Koch and M. C. Holthausen, A Chemist s Guide to Density Functional Theory, Wiley-VCH Weinheim, Germany, 2000. 

Computational Organometallic Chemistry has been written to be accessible to a general scientific audience. These pages will provide upper-division undergraduate students and graduate students with useful lessons that can be employed in their future scientific endeavors, while the applications chapters will spark future research contributions. Similarly, senior researchers, academic and industrial, who may wish to bring their energies to bear on this field will find bofh... 

M. S. Newman (Ed.), Steric Effects in Organic Chemistry, John Wiley Sons, Ltd, New York, 1956. Forarecent review classifying the components of steric effects, see D. P. White, in Computational Organometallic Chemistry, Ed. T. R. Cundari, Dekker, New York, 2001, Ch. 3. 

T. R. Cundari (Ed.), Computational Organometallic Chemistry, Marcel Dekker,... 

Stereoselective synthesis of natural products, new methods in synthetic organic chemistry, and computational organometallic chemistry in organic synthesis 5-8 highlighted reactions per month, and short reviews of organic, bioorganic, organometallic and microwave chemistry, total synthesis of natural products and multi-component reactions. 

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