CCN1CCN(c2cc(C)c3cc(NC(S)=NCCCN4CCc5ccccc5C4)ccc3n2)CC1
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?