Catalytic hydrolysis of phosphate esters by metallocomplexes of 1,10-Phenanthroline derivatives in micellar solution

Divalent metal‐ion complexes of 2,9‐bis[(methyldodecylamino)methyl]‐1,10‐phenanthroline (C₁₂Phen—M^II) in neutral Brij 35 micelles catalyse the hydrolysis of various phosphate triesters, diesters and monoesters. The catalytic activity of C₁₂Phen—M^II has been compared with that of the metal‐ion complexes of its water‐soluble counterpart 2,9‐bis[(dimethyl‐amino)methyl]‐1,10‐phenanthroline (C₁Phen—M^II). Saturation kinetics provide evidence for preliminary formation of ligand‐MII‐phosphate ester complexes, which decay to products. The hydrolysis of diphenyl 4‐nitrophenyl phosphate (1b) coordinated to C₁₂Phen—Zn^II proceeds 8700 times faster than the hydrolysis of 1b in the absence of metallocatalyst. Kinetic studies indicate that phosphate triesters containing a metal‐ion‐binding site in close proximity to the phosphoryl bond, i.e., diphenyl 5‐nitro‐2‐pyridyl phosphate (2b) and diphenyl 5‐nitro‐8‐quinolyl phosphate (3), are hydrolysed by the same mechanism as 1b.