Highly Efficient Phosphodiester Hydrolysis Promoted by a Dinuclear Copper(II) Complex

The interaction of CuII with the ligand tdci (1,3,5-trideoxy-1,3,5-tris(dimethylamino)-cis-inositol) was studied both in the solid state and in solution. The complexes that were formed were also tested for phosphoesterase activity. The pentanuclear complex [Cu5(tdciH-2)(tdci)2(OH)2(NO3)2](NO3)4·6H2O consists of two dinuclear units and one trinuclear unit, having two shared copper(II) ions. The metal centers within the pentanuclear structure have three distinct coordination environments. All five copper(II) ions are linked by hydroxo/alkoxo bridges forming a Cu5O6 cage. The Cu−Cu separations of the bridged centers are between 2.916 and 3.782 A, while those of the nonbridged metal ions are 5.455−5.712 A. The solution equilibria in the CuII−tdci system proved to be extremely complicated. Depending on the pH and metal-to-ligand ratio, several differently deprotonated mono-, di-, and trinuclear complexes are formed. Their presence in solution was supported by mass, CW, and pulse EPR spectroscopic study, too. I...