PHASE-TRANSFER CHEMISTRY OF HETEROPOLYANI ONS .1. RESEARCH ON SOLVATION BEHAVIOR OF SUBSTITUTED KEGGIN AND DAWSON ANIONS IN THE NONPOLAR-SOLVENTS

The heteropolyanions of the Keggin structure ZW(11)O(39)M(H2O)(n-)(Z = Si, Ge, P; M = Ni2+, Cu2+, Cr3+, Co2+, n = 4 similar to 6) and Dawson structure P(2)W(17)O(61)M(H2O)(n-)(M = Ni2+, Cu2+, Cr3+, Co2+, n = 7, 8) have been transferred into the non-polar solvents (benzene, toluen e), with the aid of tetraheptylammonium bromide. We found that the deh ydration reaction, which was difficult to carry out in the aqueous sol ution, could form coordinatively unsaturated site. When the polar solv ent such as acetone, pyridine etc. was added, the anhydrous heteropoly anions could rapidly recover saturated coordination state. Their elect ronic absorption spectra were similar to each other. The ESR spectra s howed activity. In the non-polar solvents, the coordination ability of pyridine is the strongest in the ligand substitution reaction. The su bstitution reaction was carried out as following: ZW(11)O(39)M(L)(n-)Py --> ZW(11)O(39)M(Py)(n-)+L (L = acetone, acetonitrile, etc.) In the mean time, we also studied how the temperature, the concentration of heteropolyanions and flow of inert gas affected the solvation behavior of heteropolyanions in the non-polar solvent. A general rule about ph ase transfer was concluded from the experiments, which will provide th e theoretical base of the catalytic research on heteropolyanions in th e non-polar solvent.