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