wherein {HEAD ~ the tertiary ligand} comprises {TAIL ~ a formula} of X2 X3 X4 X5 X6 wherein 
wherein { HEAD ~ the tertiary ligand } comprises { TAIL ~ a formula } of X2 X3 X4 X5 X6 wherein
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH