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