CN(C)CCNC(=O)c1cccc2c(NC(CCCNC(=N)N)C(=O)O)c3ccccc3[n+](C)c12.COS(=O)(=O)[O-]
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?