O=C(C[n+]1ccn(CCCNP2(=O)C=C(c3ccccc3)OC(c3ccccc3)=C2)c1)c1cccs1.[Br-]
Molecules with a polar surface area of greater than 140 angstroms squared (Å2) tend to be poor at permeating cell membranes. What's the psa of this molecule?