THE NATURE OF BIOMIMETICALLY RELEVANT RATE ENHANCEMENT OF HYDROLYSIS IN A COORDINATION SPHERE OF SQUARE-PLANAR METAL-COMPLEXES SUGGESTED BYAN X-RAY STRUCTURAL STUDY OF A,B-H,G-[PT(O-C6H4C(ME)=NOC(=O)ME)(MU-CL)](2)

X-Ray structural data for a,b-h,g-[Pt(o-C6H4C(Me)=NOC(=O)Me)(mu-Cl)](2 ) and ab initio quantum chemical calculations were used to show that t he biomimetic hydrolysis of esters and amides within the coordination sphere of a square-planar complex, in general, and the deacylation of cyclometallated aryl oxime esters, in particular, is due to the stereo chemical control which arises from the close proximity of the coordina ted OH or H2O ligand and the carbonyl carbon (O ... C separation 3.47 Angstrom) in the reactive complex [Pt{o-C6H4C(Me)=NOC(=O)Me}py(OH)] ge nerated in aqueous solution.