Controlled Hydrolysis of Phosphate Esters: A Route to Calixarene-Supported Rare-Earth Clusters.

Phosphate ester bonds are widely present in nature (e. g. DNA/RNA) and can be extremely stable against hydrolysis without the help of catalysts. Previously, we showed how the combination of phosphoryl and calix[4]arene moieties in the same organic framework (L ) allows isolation of single lanthanide (Ln) metal ions as [Ln (L ) ](O SCF ) . Here we report how by controlling the reaction conditions a new hydrolyzed phosphoryl-calix[4]arene ligand (H L ) is formed as a result of Ln -mediated P-OEt bond cleavage in three out of the eight possible sites in L . The chelating nature of H L traps the Ln species in the form of [Ln (L )((EtO) P(O)OH)] dimers (Ln=La, Dy, Tb, Gd), where the Dy derivative shows slow magnetization relaxation. The strategy presented herein could be extended to access a broader library of hydrolyzed platforms (H L ; x=1-8) that may represent mimics of nuclease enzymes.