Supramolecular polymer based on hydrogen bonding Essay

Supramolecular polymer based on hydrogen bonding - Essay Example This will lead to the development of inexpensive procedure affording urea based monomers acting the terminals of the chains. According to H1 NMR both 2-(4-(3-(3,5-bis(trifluoromethyl)phenyl)ureido) phenyl)acetic acid and 4-(4-(3-(3,5-bis(trifluoromethyl)phenyl)ureido)phenyl)butanoic acid were impossible to purify using recrystallization. However, the same method of purification was successful in case of using 4-(3-(3,5-bis(trifluoromethyl)phenyl)ureido)benzoic acid as a substrate for purificalion. This purified product was taken on to the next step where the transformation from benzoic acid derivative into two electron acceptor group was conducted introducing tetrabutylammonium hydroxide. Subsequent polymer formation was achieved through self-assembly process between two electron donating group of urea and two electron accepting group of the previously synthesized benzoic acid salt. 2) Conclusions The research provided an account on the supramolecular chemistry of a set of 1-(3,5-bis (trifluoromethyl)phenyl)-3-phenylurea derivatives. It was motivated by the extraordinary chemistry manifested by supramolecular polymers based on hydrogen bonding. The work pointed out to the substantial differences between the obtained substrates. First of all, 2-(4-(3-(3,5-bis(trifluoromethyl)phenyl)ureido)phenyl)acetic acid and 4-(4-(3-(3,5-bis (trifluoromethyl)phenyl)ureido)phenyl)butanoic acid contained impurities which were impossible to remove using recrystallization. In both cases two purification attempts were made, both unsuccessful. On the other hand the same technique was applicable in purifying 4-(3-(3,5-bis(trifluoromethyl)phenyl)ureido)benzoic acid. This fact leads to the conclusion that purification method should be changed in case of the first two derivatives should the synthesis be repeated. For example, flash column chromatography would be an attractive alternative. To conclude, an inexpensive and efficient method that allowed the production of urea based monomers was developed. The reaction affords excellent yields and the process is easy to carry out. Because tetrabutylammonium hydroxide and inorganic bases can be compared in their basic properties, it was possible to obtain the salt of the required monomer in an excellent 70% yield. The work is partly successful and due to time limits it was not possible to repeat each step again. It raised important question which will form the bases of the future work. 3) Future work First of all, in future, it is important to find efficient methods of purification products achieved in experiment one and two. By doing that it will be possible, comparing the yield, draw conclusions about formation of the intermediates. The produced intermediates will be transformed into supramolecular polymer substrates chain-stopping properties of which will be investigated. As it is seen from the first three experiments the only difference between substrates is the number of carbon atoms in the chain next to the benzen e ring. For this reason it will be possible to draw conclusions between viscosity of the formed suprapolymer and the number of carbon atoms. Solutions of the mentioned polymers are known to have high viscosity and their rheological behaviour is different in case of different polymers. For example, it was established that polymers containing ureidopyrimidinone units are different from those