Application strategies rules

To find out applications and rules of the metala-logy principle, we systematically investigated the influence of HOMO/LUMO- or LUMO/HOMO-perturbations (dual model) as well as relative donor/acceptor- or acceptor/donor-interactions (double-dual model) in metal-complexesin their model-reactions and in metal catalysis The strategy we followed is depicted in Scheme 2.2-2. For our purposes, we separated the studied catalytic system into two r-systems (substrates S Case I),... 

The dotted lines in the diagram indicate the various feedback paths that exist to enable the individual to identify if a particular stage of the processing chain was executed correctly. Thus, if the operating team had planned a strategy to handle a complex plant problem, they would eventually obtain feedback with regard to whether or not the plan was successful. Similar feedback loops exist at the rule and skill-based levels, and indicate opportunities for error correction. The application of the stepladder model to a process industry example is given in Appendix 2A at the end of this chapter. 

To build a QSPR model, one should carefully select available experimental data, and choose the initial pool descriptors (from which the program selects the most appropriate ones) as well as a mathematical approach linking those descriptors with a given property. Then, a suitable strategy of model validation should be applied in order to obtain a quantitative assessment of the quality of predictions. Finally, some rules should be established in order to prevent the application of the models to compounds too different from those used for obtaining the models. 

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