Toward a qualitative understanding of the initial electron transfer site in Dawson-type heteropolyanions

摘要: EPR, NMR, optical spectra and electrochemistry experiments on an extended series of one-electron reduced Dawson-type heteropolyanions converge to support the conclusion that equatorial (α1) tungsten atoms are first in [P2W18O62]6−. This is reinforced, for instance, by interpretation electrochemical behaviours a [P2W18−xMoxO62]6− derivatives. In search rationale, study electronic structure such means Huckel calculations provides qualitative understanding this reduction process. It found lowest unoccupied molecular orbital (LUMO), which likely be involved initial electron transfer, essentially “belt”-centred Also, change site (α1→α2) upon substitution “cap” region (α2 site) more electronegative metal centre (Mo instance) consistent with localization LUMO substituted centre(s).