CCCCCNC(=O)c1ccc2c(=O)n(CCCN3CCCC3=O)c(=S)[nH]c2c1
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?