COc1cccc(-c2[nH]c(C(=O)NCCCN3CCOCC3)cc3c4ccccc4nc2-3)c1
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?