Behzadi Far, Mohsen (2014) Determination of stability constants of 15-crown-5 complexes with Sodium cation using electronic descriptors in QSPR method. Masters thesis, University of Zabol.
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Abstract
In this project, quantitative structure property relationship (QSPR) analysis was carried out between molecular descriptors of 65 complexes derived from 1, 4, 7, 10, 13-pen-taoxacyclopentadecane ethers (15C5) and stability constants associated with sodium cation. The structure of the crown ethers was drawn and optimized using Gaussian98 and Hayperchem software. In this study, three different sets of quantum mechanical properties including charge, dipole moment, and orbital energy were calculated for quantum variables in the vacuum state. Dependence of stability constants of crown ethers on the parameters was evaluated using multiple linear regressions. Results indicated a squared linear correlation coefficient of 0.519 for 65 crown ether molecules. In the current model, electronic charge variable has a significant contribution to the stability constant of the Aforemenhoned. Although the obtain liner model interpret the mechanism of the 1,4,7,10,13 derivative stability in an excellent manner, it suffers on low power of predict ability of stability constants. As a result, nonlinear variables tried to be modeled using neural networks in order to provide better correlations in the model. Neural network model suggests a squared linear order of 0.924 for all molecules. Developed models point out that stability mechanism of the complexes is mostly of columbic reaction type. Orbital overlapping is also observed to a limited extent. In this research, interesting results was obtained suggesting that the crown ether with sodium atoms are not involved in all electro negativity atoms of oxygen inside the ether ring but some of positive-charged carbon atoms also contribute in the stability of the complex with the mediation of solvent (water) molecules.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Stability constant; Crown ethers; Electronic descriptors; QSPR |
| Subjects: | Q Science > QD Chemistry |
| Depositing User: | admin admin1 admin2 |
| Date Deposited: | 16 Apr 2016 07:47 |
| Last Modified: | 16 Apr 2016 07:47 |
| URI: | http://eprints.uoz.ac.ir/id/eprint/314 |
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