Monolayer formation, LB film fabrication of bilirubin(l), its two kinds of
amphiphilic derivatives, bilirubin dioctadecyl ester [B(COOC18H37)(2), 2] a
nd dioctadecyl bilirubinamide [B(CONHC18H37)(2), 3] at an air-water interfa
ce on subphases with different pH values and subphases containing different
metal ions were investigated and compared with 1. Some information regardi
ng the packing density in monolayers, molecular orientation and complexatio
n by metal ions has been obtained by means of many physical measurements su
ch as the pi -A isotherms, X-ray photoelectron spectroscopy, UV-visible spe
ctroscopy and low-angle X-ray diffraction. At the air-water interface the a
mphiphilic ligands with their complexing head groups in contact with the aq
ueous phase can form metal complexes with many metal ions present in the aq
ueous phase. The formation of ligand-metal complexes leads to changes in th
e area per molecule and in the collapse pressure, as well as to changes in
the XPS and UV-visible absorption spectra of the monolayer assemblies. Low-
angle X-ray diffraction indicates that the LB films of 1, 2 and 3 were Y-ty
pe with bilayer spacing of ca. 2, 50, 5, 60 and 5, 65 nm. The coordination
in ordered molecular films are much different from that in bulk solution. I
t can help us to understand the formation and prevent and cure of gallstone
s.