Interaction of Prolin, Leucine and methylurea with inorganic cluster [(PO۴)M۱۲O۳۶].nH۲O; (M= Mo, W)

Three new inorganic-organic hybrid materials based on heteropolyoxometalates, [L-C۶H۱۴NO۲]۳[(PO۴)Mo۱۲O۳۶].۳H۲O (۱), [LC۵H۱۰NO۲]۳[(PO۴)W۱۲O۳۶].H۲O (۲), and [C۲H۷N۲O]۳[(PO۴)W۱۲O۳۶].۴H۲O (۳), where C۶H۱۴NO۲, C۵H۱۰NO۲, and C۲H۷N۲O are protonatedL-leucine, L-proline, and methylurea, respectively, have been synthesized and structurally characterized by some physico-chemicalmethods. Elemental analyses, IR, Raman, mass, UV, and ۱H NMR spectroscopies of the title hybrid materials indicate that there are vander Waals interactions between O atoms of the heteropolyoxometalates and water molecules, as well as the N and O atoms of the aminoacids and methyl urea moieties. The molecular structures of synthesized hybrid materials contain discrete entities of L-leucinium,L-prolinium or methyluronium and water molecules that surround every [(PO۴)M۱۲O۳۶]۳- anion, over the extended crystalline network.The observed bands in Raman spectra of ۲ and ۳ demonstrate that [(PO۴)W۱۲O۳۶]۳- anion retains its “Keggin structure”. Between pH =۷and pH =۴ the characteristic bands of the Keggin anion [(PO۴)M۱۲O۳۶]۳−(M = Mo, W) appear at ۲۱۰ and ۲۶۰ nm in the UV spectra,respectively.

Keywords:

Polyoxometalate , L-leucine , L-proline , Methylurea , Inorganic-organic hybrid , IR , Raman , UV , ICP