One aspect of the invention relates to hexafluoroleucine and congeners thereof, and methods of making the compounds. Another aspect of the invention relates to the synthesis of protein cores comprising hexafluoroleucine and congeners thereof. Certain peptides comprising hexafluoroleucine and congeners thereof have been characterized using comparative biophysical studies. In general, the fluorinated peptides show higher thermal stability and enhanced resistance to chemical denaturation. Further, mixed hydrocarbon-fluorocarbon cores self-sort into homogeneous bundles, suggesting new avenues for the design and manipulation of protein-protein interfaces.