Investigation of dioctadecyl bilirubinamide in monolayers and Langmuir–Blodgett films

A new amphiphilic ligand, dioctadecyl bilirubinamide [B(CONHR)2, R=C18H37] form stable monolayers at the air–water interface on neutral, acidic and basic subphases as well as on subphases containing metal ions. Changes in the pH of the subphase do not produce remarkable effects on monomolecular films. The interactions between metal ions and B(CONHR)2 molecules were investigated by means of various techniques in monolayers and Langmuir–Blodgett (LB) films. B(CONHR)2 with its complexing head group in contact with the aqueous phase can form metal complexes with many metal ions present in the aqueous phase. The formation of B(CONHR)2–metal complexes leads to large changes in the area per B(CONHR)2 molecule. LB films transferred from pure water and metal ions containing subphases were characterized by XPS and low-angle X-ray diffraction.