The fluorine atom is electronegative and reduces the basicity of adjacent amines, however, it is relatively small: only about 20% larger than hydrogen and significantly smaller that chlorine resulting in unique and useful properties. In many cases incorporation of fluorine results in improved DMPK properties. Below you will find examples of mono-fluoro, di-fluoro and trifluoromethyl substituted amines, many with a hydroxyl substituent or an ether linkage.