COC(=O)[C@H](Cc1ccccc1)NP(=O)(O)OCC1OC(n2cc(C)c(=O)[nH]c2=O)CC1N=[N+]=[N-].N
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?