Bioinorganic systems, theoretical

As the preceding discussion of nitrogenase metal-sulfur clusters indicate, analysis of complex bioinorganic systems requires the use of multiple analytical techniques and the cooperative exchange of data and ideas of many researchers. The descriptions in this chapter have attempted to give students some idea of the scope and complexity of instrumental techniques available to the bioinorganic chemist. It has not been intended to be either comprehensive or theoretical in presentation. Students are encouraged to acquaint themselves further with the theory and practice of instrumental techniques, especially those that are important to their particular research interests. 

Electron transfer reactions and theory have been highlighted in this Conference. It is apparent that detailed characterization of the electron tranfer process both in the ground and excited states will be continued. The empirical and theoretical correlations of redox rate parameters with known properties of the donor and acceptor centers, the intersite distance for electron travel, and the nature of the medium (51) will continue to be amassed. Such results have been, and promise to be, important ingredients for success with bioinorganic systems (52-55). 

Theoretical Investigation of Solvent Effects and Complex Systems Toward the calculations of bioinorganic systems from ab initio molecular dynamics simulations and static quantum chemistry... 

Considerable work has already been carried out using ab initio calculations to predict the photodissociation dynamics of gas-phase metal carbonyls (45). This is a fertile area for computational work, given the extensive experimental results available, which include the use of ultrafast methods to characterize the short time behavior in photoexcited states. There is considerable evidence that surface crossings, especially of a spin-forbidden nature, play a considerable part in the dynamics. Much of the theoretical work so far has focused on reduced-dimensionality models of the PESs, which have been used in quantum mechanical smdies of the nonadiabatic nuclear dynamics, in which spin-forbidden transitions are frequently observed (45). Here, too, the potential benefits to be derived from a proper understanding of the spin-state chemistry are considerable, due to the importance of light-induced processes in organometallic and bioinorganic systems. 

Interest in metal-dithiolene complexes has increased since their initial synthesis to the present, because of their potential application as molecular materials with conducting, magnetic and opticaP properties and their involvement in bioinorganic processes at the active site of Mo and W metalloenzymes. These applications have stimulated a multidisciplinary approach to these systems which includes theoretical smdies and use of sophisticated characterization methods, furnishing a deep understanding of the struc-ture/property relationship. This allows chemists to tailor metal-dithiolene complexes... 

---