Bachelor of Science

In conjunction with the preparation of organotin adducts, a series of Schiff bases (L), 2-HOC6H3(X)CH=NR and Mannich bases (LH), 2-HOC6H3(X)CH2NHR have been synthesised. Furthermore, X-ray crystallographic study has shown that there is an intramolecular proton transfer reaction in LH5 (X=5-NO2, R=CH2CH2NMe2) and an intermolecular transfer reaction in LH9 (X=5-C1, R=CH2CH2NMe2). Hence, the aim of this project is firstly to investigate and interpret the spectroscopic data of L1-L9 and LH1-LH9 so that these data are in accordance with the results of the X-ray structural study. Secondly, attempts are made to synthesise a LH compound which will demonstrate the process of an intramolecular bonding only. Finally, a preliminary study is done to probe the possibility of using the "reaction types", of which transfer reaction is included, for the teaching of organic chemistry curriculum.

From those compounds newly synthesised (L10-16, LH10-16), it can be gathered from the IR and NMR spectroscopic studies that a six-membered intramolecular hydrogen bonding is present in the Schiff bases. In cases when the substituent is a strong electron withdrawing nitro group, an intramolecular proton transfer process is expected. For the Mannich bases, the presence of an intermolecular proton transfer process is possible in LH10 (X=5-N02, R=CH2CH2CH2NMe2) and LH11 @=5-N02, R=CH2C6H5) promoted by the acidity of the phenolic proton in them. Finally, LH13 (X=3-OCH3, R=CH2C6H5) is found to most likely exist as a monomer consisting of an intramolecular hydrogen bonding.