NEW PERSPECTIVES IN POLYOXOMETALATE CHEMISTRY BY ISOLATION OF COMPOUNDS CONTAINING VERY LARGE MOIETIES AS TRANSFERABLE BUILDING-BLOCKS - (NME4)5[AS2MO8V4ASO40]CENTER-DOT-3H2O, (NH4)21[H3MO57V6(NO)6O183(H2O)18]CENTER-DOT-65H2O, )18(NH4)6[MO57V6(NO)6O183(H2O)18]CENTER-DOT-14H2O, AND (NH4)12[MO36(NO)4O108(H2O)16]CENTER-DOT-33H2O

The compounds (NMe4)5[As2Mo8V4AsO40] . 3 H2O 2a, (NH4)21[H3Mo57V6(NO)6 O183(H2O)18] . 65 H2O 3a, (NH2Me2)18(NH4)6[Mo57V6(NO)6O183(H2O)18] . 1 4 H2O 3b and (NH4)12[Mo36(NO)4O108(H2O)16] . 33 H2O 4a (3a and 4a were not correctly reported in the literature regarding to their compositi on, structures and the oxidation states of the metal centres) which co ntain large isolated anionic species, have been prepared (among them 3 a, 3 b, and 4 a in rather high yield) and characterized by complete c rystal structure analysis as well as IR/Raman, UV/VIS/NIR, ESR spectro scopy and magnetic susceptibility measurements, redox titrations, bond valence sum calculations, elemental analyses and thermogravimetric st udies. Perspectives for polyoxometalate chemistry referring to the syn thesis of ''extremely'' large nanoscaled species are discussed, togeth er with the occurrence of a large transferable {Mo17} building block i n the compounds 3a, 3b and 4a which also exists in the corresponding i ron compound Na3(NH4)12[H15Mo57Fe6(NO)6O183(H2O)18] . 76H2O 7a.