Synthesis and Characterization of Polyvanadium and Heteropoly-Tungsten Based Inorganic Wells Dawson Polyoxometalates Hybrids

Abstract

The two new Wells-Dawson type polyoxometalatehybrids named as [(C4H9)4N]10H2[{C7H14O4C(CH2O)3P2V3W15O59] (D.Poms@Lig1), [(C4H9)4N)]5H2[C2H4OC(CH2O)3 P2V3W15O59] (D.Poms@Lig-2) have been synthesized with good percentage yields (65 and 75%, respectively). The newly prepared hybrids were characterized successfully by FT-IR, 1H, 13C, 31P, 51V NMR and UV-Visible spectroscopic methods. Parent Dawson polyoxometalates and ligands molecules display the strong metal-oxo (V–O) vibrational bands at 700 cm–1. After interaction, there is a little fluctuations in these vibrational bands and appeared at 757 and 750 cm–1 for V–O of D. Poms@Lig-1 and D.Poms@Lig-2, respectively. The strong peaks appeared at 824, 718 and 803, 754 cm–1 are assigned for ν(W–O–W) D.Poms@Lig-1 and D.Poms@Lig-2, respectively. In 1H NMR, the chemical shift value 2.95–2.94 ppm was observed C–CH2–O for D.Poms@Lig-1 and D.Poms@Lig-2, respectively. In 13C NMR, signal appears at 62.92 and 62.75 ppm are assigned for –CH2–C–CH2– for D.Poms@Lig-1, D.Poms@Lig-2, respectively. 51V NMR spectra showed peaks at –541.00 and –541.87 ppm for D.Poms@Lig-1 and D.Poms@Lig-2, respectively. 31P NMR spectra showed two peaks at δ = [–13.44, –7.19] ppm and [–13.44, –7.25] ppm for D.Poms@Lig-1, and D.Poms@Lig-1, respectively. The UV-Visible absorption spectra showed that there is just a little bit change in the intensity of the absorption bands among the absorption spectra of the ligands, hybrid compounds and parent Dawson POM.