and wherein T3 is a timing or linking {TAIL ~ group} which functions by electron transfer down {HEAD ~ a conjugated chain} and is represented by the formula ##STR25## wherein *** denotes the point of attachment to E2 and **** denotes the point of attachment to PUG 
and wherein T3 is a timing or linking { TAIL ~ group } which functions by electron transfer down { HEAD ~ a conjugated chain } and is represented by the formula # # STR25 # # wherein * * * denotes the point of attachment to E2 and * * * * denotes the point of attachment to PUG
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD 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 OTH OTH OTH OTH OTH OTH OTH OTH