Theoretical Study On The Structures And Synthesis Mechanism Of Partial Organic Germanium Compounds

Carboxyethylgermanium sesquioxide has potential antitumor activities and a low level of toxicity, which is beyond compared with other pharmaceuticals. In recent years, there is a growing interest in the organic germanium for its biologic activity. As a result, the organicgermanium chemistry has became the foreland of science and technology, and now it has attracted attention of many researchers who want to develop the more prominent antitumor pharmaceuticals. Therefore, the systematic theoretical elucidations of its synthetic mechanism will have not only high academic values but also broadly applied foreground, especially, the compounds ofβ-carboxyethyl organogermanium quioxide (R-Ge-1) and bis-β-carbamylethyl organogermanium ioxide (R-Ge-2).In this thesis, many important reactions involved in the synthesis processes of R-Ge-1 and R-Ge-2 have been studied using ab initio electronic calculations and density function theory. The content of this paper is divided into two main section.1. In the section of theoretical study on the reaction mechanism ofβ-carboxyethyl organogermanium quioxide (R-Ge-1), we have systematicly studied the following reaction steps: GeHCl₃+CH₂=CHCOOH→GeCl₃CH₂CH₂COOH (1) GeCl₃CH₂CH₂COOH+H₂O→GeCl₂OHCH₂CH₂COOH+HCl (2) GeCl₂OHCH₂CH₂COOH +H₂O→GeCl(OH)2CH₂CH₂COOH+HCl (3) GeCl(OH)2CH₂CH₂COOH+H₂O→GeCl(OH)3CH₂CH₂COOH+HCl (4)2. In the section of theoretical study on the reaction mechanism of bis-β-carbamylethyl organogermanium ioxide (R-Ge-2), we have systematicly studied the following reaction steps: GeCl₃CH₂CH₂COOH+SOCl₂→GeCl₃CH₂CH₂COCl+SOClOH (5-1) GeCl₃CH₂CH₂COOH+SOClOH→GeCl₃CH₂CH₂COCl+SO(OH)2 (5-2) GeCl₃CH₂CH₂COCl+H₂O→GeCl₂OHCH₂CH₂COCl+HCl (6) GeCl₂OHCH₂CH₂COCl+H₂O→GeCl(OH)2CH₂CH₂COCl+HCl (7) GeCl(OH)2CH₂CH₂COCl+H₂O→Ge(OH)3CH₂CH₂COCl+HCl (8)The important and value results in this thesis can be summarized as follow:The reactants, products and transition states of the reactions have been optimized using Density Function Theory, and all of the transition states have been verified to connect with the designated reactants and products by performing intrinsic reaction coordinate (IRC) analysis at the same level. In the reaction of (1), Geometries of reactants, transition states, and products have been optimized respectively at the B3LYP/6-311++G (3df, 3pd) level, and the relativistic effective core potentials of Ge atom are considered using the LANL2DZ basis (ExtraBasis). In gas phase, we obtain five stable equilibrium structures (three reactans and two products), and five kinds of TSs which have rather early character. This reaction has five possible reaction channels. Solvent effects (in gas phase and in the solvents of THF, acetone, and DMSO) are taken into account with PCM model, the preliminary study shows that the complex formation is favored by the use of polar solvent. The preliminary study shows that the complex formation is favored by the use of polar solvent, and also shows the dominating reaction pathway both in the gas and in the solvents.In the reaction of (2), we have thoroughly explored it by DFT method at B3LYP/6-31++G(2d, 2p) level and by the method of the canonical variational transition-state theory with the small-curvature tunneling effect. Both the reaction mechanism and the rate constants are reported over the temperature range of 200-2000K. The dynamic calculations and the solvent effect calculates show that the leading pathway proceeds differently over the whole temperature range in gas phase and in the solvent of water.In the reaction of (3), the mechanism and dynamical properties have been investigated theoretically. Three reaction channels are found. Geometries, vibrational frequencies, IR intensities and relative energies for various stationary points in the three reaction channels have been determined respectively at the B3LYP /6-311G (d, p) level. Every transition state was verified to connect the designated reactants and products by performing an intrinsic reaction coordinate (IRC) analysis. The corresponding thermodynamics and kinetics for the three reaction channels have been deduced over a wide temperature range of 300-1000 K by using transition-state theory (TST).In the reaction of (4), the mechanism and dynamical properties have been investigated at the B3LYP /6-311G (d, p) level, the transition state of chlorin atom parallelling the C=O bond is located and also is performed by an intrinsic reaction coordinate (IRC) analysis.In the reaction of (5), we have thoroughly explored it by DFT method at B3LYP /6-311G (d, p) level, five possible reaction channels are found in the two steps of crylic acid chlorizating reaction. We obtain the dominating reaction pathway in each step.In the reaction of (6), (7), (8), we have located the transition states and analysed the dominating reaction pathway.We make great efforts to get the systemic and accurate results during the study. Actually, many valuable results are obtained. This will guide promise the development of theoretical and practical study on the carboxyethylgermanium sesquioxide.