Effect of Substituent Location on the Thermodynamic Properties of Cholesteryl Halobenzoates and Halocinnamates

A series of substituted aromatic esters of cholesterol has been examined by DSC. Temperatures and heats of transition were measured. A special modification of the cholesteric mesophase was noted in the 3-chloro and 4-bromo benzoate esters by microscopy. A series of statements has been formulated from these observations which permit the prediction of transition temperatures as well as entropies as a function of the modification of a parent compound whose properties are known within the cholesteryl ester series.