Selective synthesis and self-organization at the air/water interface of long chain fluorinated unsaturated ethyl esters and alcohols

Different methods for the selective synthesis of diastereomeric ethyl 2-fluoroalk-2-enoates 1 and 2 and 2-fluoroalk-2-en-1-ols 3 and 4, derived from the esters by reduction, with 16 and 18 carbon atoms were developed. The phase behavior of the synthesized compounds at the air/water interface was investigated by Langmuir film balance measurements and Brewster angle microscopy (BAM) and compared to that of the corresponding non-fluorinated parent compounds. While the phase behavior of the esters is dominated by the influence of the ethyl moiety in the head group and the configuration of the double bond, in the allylic alcohols the presence or absence of a vinylic fluorine substituent is crucial for the morphology and the stability of the monolayers. In addition, in the case of alcohols the fluorine prevents the crystallization.