R14 and {HEAD ~ R15} are each, independently, hydrogen, {TAIL ~ alkyl} of 1 12 carbon atoms, n Ar, p NR16 R17, or p N+R16 R17 R18 Y  
R14 and { HEAD ~ R15 } are each , independently , hydrogen , { TAIL ~ alkyl } of 1 12 carbon atoms , n Ar , p NR16 R17 , or p N+R16 R17 R18 Y
OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH