Three additional advantages flow from the ease of separating {HEAD ~ excess metallating reagents} from {TAIL ~ the metallated crystalline polymer} 
from
Three additional advantages flow from the ease of separating { HEAD ~ excess metallating reagents } from { TAIL ~ the metallated crystalline polymer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL