NONLINEAR-OPTICAL CHARACTERIZATION OF LANGMUIR AND LANGMUIR-BLODGETT-FILMS OF AN AMPHIPHILIC COORDINATION COMPOUND

Pentacyano(4-octadecylaminopyridine)ferrate(III) salts (POF) were synt hesized and were shown to produce a stable Langmuir monolayer on a pur e water subphase when the counter cation is chosen so as to enhance th e hydrophobic character of this amphiphilic coordination compound. Sec ond-harmonic generation measurements carried out on the monolayer indi cated that POF molecules are very tilted and present a large second-or der molecular hyperpolarizability. Langmuir-Blodgett (LB) films up to 60 layers were fabricated by means of the horizontal lifting method; h owever, X-ray diffraction experiments revealed an unexpected Y-type bi layer structure. The centrosymmetric character of these LB films was c onfirmed by the absence of a second harmonic generation property.