Aminobenzylphosphonate functionalized polyoxometalates

The phosphonic acid H2O3PCH2C6H4(NH3)2 has been obtained by acidic hydrolysis of the corresponding ester, and the functionalized (NH4)2[Mo5O21(PCH2C6H4NH3)2] (1) POM was prepared by reaction of the phosphonic acid with a solution of molybdate. (1) was characterized by IR, 31P NMR and single-crystal X-ray diffraction analysis. Five MoO6 octahedra are linked by edges and corners to form the {Mo5O21} ring from which two monoaminobenzylphosphonates are dangling. The phenyl groups of the organic branches orientate in the solid state to form p–p stacking. The molecular structure is stable in dmso solution on the basis of 31P NMR. Similarly, (NH4)2 [Mo5O21(PCH2C6H3(NH3)2)2] 2 was obtained by reaction of diaminobenzylphosphonate with the {Mo5O21} inorganic core. IR, 31P NMR spectra confirm the structure of 2 is identical to that of 1. q 2004 Elsevier B.V. All rights reserved.