Solvent Effect on The Absorption Spectra of Acetylpyridines And Their N-Oxides

The electronic absorption spectra of acetylpyridines and acetylpyridine N-oxides were in- vestigated in some organic solvents of varying polarities. The spectra indicate the presence of two absorption bands (A) and (B), the first is assigned to the local TT —> transition and the se- cond is assigned to TC -> "* transition influenced by charge transfer (C.T.) interaction. The n was observed as a shoulder in non-polar solvents and disappeared completely in polar solvents. The C.T. nature of the band (B) is asscertained and its position is discussed in relation to mole- cular structure and solvent effect.