COc1ccc(-n2nnnc2C(c2cccs2)N2CCC3(CC2)C(=O)NCN3c2ccccc2)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?