where {HEAD ~ R1} is {TAIL ~ the linker} and the C3 group is the triphos part 
where { HEAD ~ R1 } is { TAIL ~ the linker } and the C3 group is the triphos part
OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH