Second, recovering {HEAD ~ the metallated polymer} in {TAIL ~ the active form} allows concentration thereof for further reaction 
in
Second , recovering { HEAD ~ the metallated polymer } in { TAIL ~ the active form } allows concentration thereof for further reaction
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH