Abstract
The conformation and intramolecular CH/pi interaction of para-substituted aromatic ketones(p-XC6H4CHR1COCHMe2) and amines(p-XC6H4CHR1NMeCHMe2) (where, X= OMe, Me, H, Cl, NO2 : R1= H, Me) were studied by NMR and IR methods. The intramolecular CH/pi interaction of CH (isopropyl group) /pi approached conformer were expected 95% in ketones and 25% in amines by molecular mechanics (MM) calculation. 1H(2D)-chemical shift, difference NOE spectra and absorption bands in the C-D region were measured. The substituent effect on aromatic ring (CH acceptor) and effect of the electronegative substituent on CH donor (CO < NMe) support the hydrogen-bond-like nature of CH/pi interaction. In amides, stable five-membered ring CH/pi interaction can formed between NMe CH proton and aromatic ring, this conformer is also pedomintly.
