Synthesis, Characterization, and Investigation of Cobalt(II) Complexes as Mimics of Phosphoesterases

Drawing inspiration from biological systems, the development of a catalyst that can perform the hydrolysis of phosphoesters at a rate similar to that of phosphatases in nature has been pursued for decades. Although many catalysts containing various metals have been reported in literature, none have come close to replicating the rates of the natural enzymes, particularly in aqueous media. In an attempt to further expand the array of model catalyst, the ligands N-[2-carboxybenzomethyl]-N-[carboxymethyl]-β-alanine, H3camb, and N,N'-Bis[2-carboxybenzomethyl]-N,N'-Bis[carboxymethyl]-1,3-diaminopropan-2-ol, H5ccdp, have been employed in the synthesis and crystallization of three and full characterization of two novel cobalt(II) complexes. The complexes [Co(H2O)4Co2(camb)2(H2O)2]∙3H2O and (NMe4)2[Co2(ccdp)(µ-OAc)]·CH3CN have been studied for their activity towards catalyzing the hydrolysis of phosphoesters under Michaelis-Menten conditions in basic aqueous solutions. Lineweaver-Burke linearization was then used to determine the kinetic parameters Vmax, Km, and kcat for the two cobalt complexes.