Oc1ccc2ccccc2c1NCn1nc(CCCCCCCCc2nn(CNc3c(O)ccc4ccccc34)c(=S)o2)oc1=S
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?