NS(=O)(=O)c1ccc(CCNc2ccn3nc(-c4ccc(OCCN5CCOCC5)cc4)cc3n2)cc1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?