Study On The Photochemistry Of Dimethylhydantoin And Design And Synthesis Of Tripodal Host Molecule

The dissertation is composed of two parts.In the first part, the photo-reaction of 5,5'-dimethylhydantoin was investigated. Its photolysis products were charactered by GC-MS, 1H NMR,UV, IR. The photolysis mechanism was proposed as: under the irradiation of 254 nm UV, theσ-bond between C4-C5 in 5,5'-dimethylhydantoin underwent cleavage, which resulted in the formation of isocyanate as the intermediate. Then the formed isocyanate reacted with the alcohol to form ester, or with water to undergo decarboxylation to form the 1-isopropylurea. The mechanism was confirmed with the trace of GC-MS, 1H NMR by the designed experiments. The 1,1'-methylenebis-(5,5'-dimethylimidazolidine-2,4-dione) was synthesized and determined by 1H NMR. Its photo-reaction with alcohol and water was studied. The mechanism of 1,1'-methylenebis-(5,5'-dimethyl imidazolidine -2,4-dione) was different from that of 5,5'-dimethylhydantoin.In the second part, the 1,3,5-trimethyl-2,4,6-tribromomethyl benzene was employed as the starting material for the synthesis of six tripodal derivatives. The starting material favoured the desirable preorganisation of the three pendant arms towards the same face of the benzene core and was more readily prepared. The tripodal derivatives with the cage or capsule structure and three binding sites are of great importance in the recognition in multi-hydroxyl compounds, metal ions, anions. Their structures were determined by ¹H NMR, ¹³C NMR and the X-ray diffraction method. The fluorescence spectroscopic titration was conducted to study the interaction between one of the tripodal hosts and metal ion.