FLUORESCENCE MICROSCOPY STUDY OF CHIRAL DISCRIMINATION IN LANGMUIR MONOLAYERS OF N-ACYLVALINE AND N-ACYLALANINE AMPHIPHILES

Monolayers of L- and of racemic N-palmitoylvaline, N-stearoylvaline, and N-palmitoylalanine have been investigated using fluorescence microscopy and surface pressure isotherm measurements. The condensed phase domains formed from the racemic films of the valine derivatives exhibited large arms curved clockwise or counterclockwise with equal probability. Very rapid compression resulted in the formation of globular domains in the racemic films of the valine derivatives. In contrast, the condensed phase domains formed from the racemic films of the alanine derivative were irregular and branched, indicating a sensitivity to the head-group size. The monolayers of the pure L enantiomers of all these compounds exhibited dendritic growth of the condensed phase.