Investigation of molecular and radical structures of ethylene glycol

摘要

In this study, the conformational variety of ethylene glycol molecule was theoretically searched via energy minimization calculations carried out by using the Merck Molecular Force Field (MMFF) and eight stable conformers were determined for the free molecule. For each of the found conformers, a geometry optimization calculation was performed by using the DFT/B3LYP method and 6-311++G(d,p) basis set. From these calculations some structural data of the conformers, such as optimized geometry, relative energy and dipol moment, were obtained and then they were used in evaluation of the stabilities of the investigated conformers. In the next step of the study, theoretically possible forteen radicals were derived from the most stable conformer of free ethylene glycol and geometry optimization was also performed for each of them. Afterwards, the "Electron Paramagnetic Resonance (EPR)" parameters of these radicals were calculated using DFT/B3LYP method and TZVP basis set and then the obtained values were compared to the corresponding experimental data reported in the literature. The results have demonstrated that the experimentally observed EPR parameters match the theoretical EPR values obtained for the model radical called here "Rad 5" (COHCH2OH). The model "Rad 5" is an anion radical formed by abstraction of an hydrogen atom from the neutral free molecule.