CCCCC(=O)Nc1ccc2c(C)cc(-c3ccc(-c4cc(-c5ccc(C)cc5)cc(-c5ccc(-c6cc(C)c7ccc(NC(=O)CCCC)nc7n6)cc5)n4)cc3)nc2n1
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?