{TAIL ~ R11} is independently selected from the group consisting of alkyl and {HEAD ~ aryl}; and 
{ TAIL ~ R11 } is independently selected from the group consisting of alkyl and { HEAD ~ aryl } ; and
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH