The method of claim 47, wherein the molecule has the formula wherein if R4 is an aryl group, then R2 is a hydrogen; heterocyclic; alkyl; aryl; or a phenyl group, the phenyl group optionally being substituted with an alkyl, halo, amino, or a thiol group; and if R2 is an aryl group, then R4 is hydrogen; heterocyclic; alkyl; aryl, or a phenyl group, the phenyl group optionally being substituted with