1	HF1	4-(2-hydroxy-4-fluorophenylthio)-butylphosphonic acid	1.000
2	HE1	4-(2-hydroxyphenylthio)-1-butenylphosphonic acid	0.941
3	HSP	4-(2-hydroxyphenylsulfinyl)-butylphosphonic acid	0.889
4	NHP	4-(2-aminophenylthio)-butylphosphonic acid	0.833