MD Simulation Of Ethene Diffusion In H[AI]ZSM-5 And QM Study On Enantioselective Reduction Of A Series Of β-Aminoketones

Two parts are included in this thesis.In the first part, concentration dependence of ethene diffusion in the lattice of H[Al]ZSM-5 has been studied by molecule dynamics (MD) simulation and the application of MD studies on molecular diffusion in zeolites was reviewed. It was found that the interactions between ethene molecules increase with the increasing of molecular concentration, while molecular total self-diffusion coefficient decreases with the concentration.In the second part, AMI and HF/STO-3G methods have been used to study the enantioselective reductions of a series of -aminoketones namely 1-(4-x-phenyl)-3-morpholin-4-yl-l-propane (x =H, Cl, Br, CH3) with borane catalyzed by (R)- or (S)-4-benzyl-5,5-diphenyl-l,3,2-oxazaborolidine. HF/STO-3G method has been used to study the enantioselective reaction mechanism, and the effect of 2 mol BH3 in the reaction has been discussed. AM1 calculations of the enantioselective reductions of a series of -aminoketones show that step 1 and 3 in the CBS mechanism are exothermic, while step 2 and 4 are endothermic, and the heats of reaction of step 4 are more than those of step 2. The product of hydrogen transfer in step 3 exhibits a B-O-B-N tetra-atomic ring. The optimized structures of R and S configurations and their thermodynamics data such as enthalpies and entropies of the transition states in step 2 have been obtained from dynamic calculations. The calculated optical activities (e.e.% values) of the final products in thisseries of enantioselective reductions are in good agreement with the experimental results.