{HEAD ~ The compounds} of this invention have the general formula ##STR2## wherein R is {TAIL ~ OH}, CO2 H, NH2, or NCS and each of x and y, independently, is an integer selected from 1 to about 10 
{ HEAD ~ The compounds } of this invention have the general formula # # STR2 # # wherein R is { TAIL ~ OH } , CO2 H , NH2 , or NCS and each of x and y , independently , is an integer selected from 1 to about 10
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH