Spectroscopic Investigation of some Thio Schiff Bases

Chemistry Depattment. Faculty of Science, Cairo University, Cairo, Egypt

Manuscript received 21 May 1993, revised 18 April 1994, accepted 27 May 1994

Schiff bases of 2-aminothiophenol with some benzaldehyde derivatives have been prepared. The effect of substitution at the benzal ring on the band positions of ^ʋC=N and ^𝛿CH(CH=N) is investigated; the electron-withdrawing groups lower the frequency as a result of decreased electron density on the C=N linkage while electron-donating groups exert an opposite effect. Band assignment of the proper absorption band is made and correlated with the non-coplanar structure assumed to the Schiff base molecules; the effect of substitu­ents is also studied. The chemical shifts of the different types of protons in the nmr spectra of the prepared Schiff bases are also reported.