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