| title: | Determination of the averaged values of the substituent constants proceeding from the as possible large and variable sets of the data series |
|---|---|
| reg no: | ETF6476 |
| project type: | Estonian Science Foundation research grant |
| status: | accepted |
| institution: | University of Tartu |
| head of project: | Natalia Palm |
| duration: | 01.01.2005 - 31.12.2008 |
| description: | During the years of the development of the method of the correlation equations in chemistry, different sets of the substituent constants for quantitative description of the substituent effect are suggested. This is true for the inductive effect, as well for scales reflecting the influence of the different resonance and steric effects. Different authors use different approaches and standard processes for the determination of these scales. Scarce attempts to calculate the sets of averaged values of substituent constants use not fully correct and universal techniques. The problem of the real universality of substituent constants is not correctly proved till now. At the Department of Chemistry of Tartu University during several decades the modified methodic of the application of multiparameter correlation equations has been developed. The corresponding software package has been created. The approximate orthogonalization of the sets of descriptors has been introduced. This is based on the "purification" of the descriptors from the contributions related to their mutual interdependence. The program enables the iterative calculation of the averaged values of the descriptor scales (for instance, substituent constants). In this procedure, it is possible to use only the data series described precisely enough. Additionally, the computerized database of the rate and equilibrium constants of chemical reactions has been created. This one enables the automatic compilation of the sets of data series using preliminarily defined rules for their selection. Therefore, the required preliminary conditions are created for the correct wholesale processing of corresponding data on the structural effects on the reactivity and other processes. For properly selected data series, the parameters characterizing these processes as well as the averaged values of substituent constants could be calculated and generalized. The aim of this project is to accomplish such general data processing making use of all available data. It is worth to notice that the technique created enables to involve to treatment the practically unlimited number of parallel values of data for the same substituent. These parallel data could be subjected to different kinds of separate processing in the combination with the treatment of the whole set of data. The final goal of the project is, on the one hand, the creation of system for the broad prognostification of the data. On the other hand, the recalculated averaged substituent constants enable to draw more informative picture on the field of their physical and chemical meaning. The real required number of the residual ("purified") substituent constants could be determined, too. |
| project group | ||||
|---|---|---|---|---|
| no | name | institution | position | |
| 1. | Natalia Palm | University of Tartu | research associate | |
| 2. | Viktor Palm | University of Tartu | Professor emeritus | |
| 3. | Maire Tamme | University of Tartu | chemist | |
| 4. | Tiina Tenno | University of Tartu | research associate | |