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

Chemistry. 2023 Mar 1;29(13):e202203525. doi: 10.1002/chem.202203525. Epub 2023 Jan 26.

Abstract

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 (LPO ) allows isolation of single lanthanide (Ln) metal ions as [LnIII (LPO )2 ](O3 SCF3 )3 . Here we report how by controlling the reaction conditions a new hydrolyzed phosphoryl-calix[4]arene ligand (H3 LHPO ) is formed as a result of LnIII -mediated P-OEt bond cleavage in three out of the eight possible sites in LPO . The chelating nature of H3 LHPO traps the LnIII species in the form of [LnIII (LHPO )((EtO)2 P(O)OH)]2 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 (Hx LHPO ; x=1-8) that may represent mimics of nuclease enzymes.

Keywords: calix[4]arene; hydrolysis; lanthanides; phosphate ester.