Abstract: Solvent effect on the conformations of α,ω-bis(4-nitrophenoxy)-alkanes with different chain lengths(N_n) was studied by UV spectra. In poor solvents such as EG-H_2O and THF-H_2O, with the increase of water content, the K-bands of N_4, N_5, N_6 and N_(10) in the UV absorption spectra shifted to longer wavelengths as compared with 4-nitrophenoxyethane(N_0). It is suggested that in poor solvents the two aromatic groups are close in parallel to each other, forming ground state complexes. The K-band of N_4 showed a blue shift from that of N_0 when the water content was around 5% this may probably be attributable to a conformation with the nitro group of one benzene ring siting on the plane of the other benzene ring.

Key words: Solvent effect, Conformation, Hydrophobic-lipophilic interaction, Ultraviblet spectra