Synthesis And Characterization Of Macrocycle Dipyridylamid Ligand

This thesis reviewed the olefin epoxidation, compared the advantagesand disadvantages of each catalysis system, then designed and synthesizedthe novel macrocycle dipyridylamid N4 Ligand.The novel ligand has the advantage of metal porphyrin that is easilyto complex with different metal ions and has not the disadvantages ofthe macrocycle porhyrin ligand that is hard to modify the substitutes.The novel ligand is prepared form coupling pyridine acid and diamine.The catalytic effects can be investigated by modifying substitutes onpyridine ring or diamine to change space effect, and electric propertyof the ligand, by introducing chiral center and by increasing solubilityin order to reach the best conversion and e.e. value. In addition, withfour nitrogen atoms, the novel ligand is easy to conjugate with differentmetals to prepare metal complexes. The introduce of pyridine ring wouldenhance the stability of complexes since 1)the pyridine ring couldenhance the antioxidant activity of ligand; 2)unpaired electronics onthe nitrogen atom of pyridine ring could directly conjugate with centremetal so that theπ-d interaction between the pelectronics of pyridinering and dorbit of centre metal to would change the charge distributionof centre metal and therefore improve the catalytic activity andselectivity; 3) the nitrogen of pyridine and amide can conjugate withthe metal to form the stable multi-tooth complexes. The complexesprepared by this kind of ligands and metals have the similar structurewith metal porhyrin, which is the stable N4 marcocycle metal complexstructure. This compounds are easy to be synthesized and have thepotential influence on chiral metal catalysis. Thus, the investigationof synthesis and characterization of catalytic properties closeN' N-bispyridiylamide macrocycle complexes have both significance inboth fundamental research and application. The author investigated nearly all kinds of the possible synthesisroutes of s-tetrazine in this thesis. It is found that s-tetrazinederivatives prepared from aldehydes, nitriles and amidines are muchconvenient than from other reagents. In particular, s-tertazinederivatives with aromatic substitutes at 3,6 positions are suitablyprepared from nitriles with catalysis of sulfur powder.The author investigated the influence of reagents, temperature,reaction duration on preparation of hydrated 3,6-dimethyl-hexahydrogen-s-tetrazines derivatives from aldehydes. Using fresh preparedacetaldehyde by decomposing trimetaldehyde received nearly two timesyield than using commercial aldehydes. The yield was increased by keepingreaction temperature at -5-0℃while tremendously decreased whentemperature was over 20℃. In addition, the yield was increased 10-20%than that of the literature by prolonging reaction duration andcontinuously filtered out white crystal produce. The author alsoinvestigated the influence of the catalyst and reaction duration onpreparation of 3, 6-dimethyl-hexahydrogen-s-tetrazines. It is found thatthe yields were low after one day reaction while greatly increased afterthree days reaction. The yields were not increased after five daysreaction and even some of them were decreased, and the color of thereaction turned to straw yellow from yellow. Thus, the best reactionduration is three days. We also found that 5% Pd/C is better than 10%Pd/C. Increasing the amount of catalyst could increase the yield whereascontinually increasing catalyst was not helpful for the yield. We foundthat the best rate of amount of substrate to amount of catalyst was 25to 1.In preparation of s-tetrazines from nitriles, it is found that3, 6-dimethyl-hexahydrogen-s-tetrazines could not be prepared fromacetonitrile reacted with hydrazine hydrate with catalysis of sulfur. However, 3, 6-diphenyl-1, 2-dihydrogen-s-tetrazines, 3, 6-dibenzyl-s-tetrazines, 3, 6-dichlorophenyl-s-tetrazines, and 3, 6-dichlorobenzyl-s-tetrazines were successfully prepared from hydrazine hydrate reactedwith corresponding nitriles. Thus, this synthesis route is a convenientway to prepare s-tertazine derivatives with aromatic substitutes at 3, 6positions, but not suitable for preparing s-tertazine derivatives withaliphatic substitutes at 3,6 positions.