Syntheses of azobenzene derivatives having fluoroalkyl chain and their monomolecular film formation at the air/water interface

The compounds, 4-(nonafluorobutyl)aniline, 4-(tridecafluorohexyl)aniline, and 4-(heptadecafluorooctyl)aniline were prepared by the reaction of corresponding perfluoroalkyl iodide with 4-iodoaniline in the presence of copper bronze. Six azobenzene derivatives (4-(4-fluorophenylazo)phenol, F(C6H4)N=N(C6H4)OH (1) (C6H4 = p-phenylene), 4-(4-trifluoromethylphenylazo)phenol, CF3(C6H4)N=N(C6H4)OH (2), 4-(4-heptafluoropropylphenylazo)phenol, C3F7(C6H4)N=N(C6H4)OH (3), 4-(4-nonafluorobutylphenylazo)phenol, C4F9(C6H4)N=N-(C6H4)OH (4), 4-(4-tridecafluorohexylphenylazo)phenol, C6F13(C6H4)N=N(C6H4)OH (5), and 4-(4-heptadecafluorooctylphenylazo)phenol, C8F17(C6H4)N=N(C6H4)OH (6)) were prepared by the usual diazo coupling reactions using 4-(perfluoroalkyl)aniline and phenol. The monomolecular film formations of the azobenzene derivatives at the air/water interface were investigated by surface pressure measurements to be dependent on the fluoroalkyl chain length (n). The compounds 5 (n = 6) and 6 (n = 8) formed stable mo...