O-Acylation of Heteropolyanions Containing Two Adjacent Vanadium Atoms

摘要

Reaction of Keggin- or Dawson-type heteropolyanions containing two adjacent vanadium atoms with acetic anhydride in the presence of acid produced acylated anions. Heteropolyanions with one or no vanadium atom do not react under the same conditions, indicating that the acyl group is attached to the bridging oxygen atom between the two vanadium atoms. A characteristic infrared band at 1760 cm-1 was observed for the acylated anions. The 8-line EPR spectrum shows that one of the vanadium atoms is reduced to ゴ(コ ). The acylated heteropolyanions are easily hydrolyzed, and its acyl group can also be transferred to aniline.