provided that at least one of R3, {HEAD ~ R6} or {TAIL ~ R8} is SO3 X; and 
provided that at least one of R3 , { HEAD ~ R6 } or { TAIL ~ R8 } is SO3 X ; and
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH