New Perspectives in Polyoxometalate Chemistry by isolation of compounds containing very large moieties as transferable building blocks: (NMe₄)₅[As₂Mo₈V₄AsO₄₀] · 3H₂O, (NH₄)₂₁[H₃Mo₅₇V₆(NO)₆O₁₈₃(H₂O)₁₈] · 65 H₂O, (NH₂Me₂)₁₈(NH₄)₆[Mo₅₇V₆(NO)₆O₁₈₃(H₂O)₁₈] · 14 H₂O, and (NH₄)₁₂[Mo₃₆(NO)₄O₁₀₈(H₂O)₁₆] · 33 H₂O

Abstract

Abstract The compounds (NMe 4 ) 5 [As 2 Mo 8 V 4 AsO 40 ] · 3 H 2 O 2a , (NH 4 ) 21 [H 3 Mo 57 V 6 (NO) 6 O 183 (H 2 O) 18 ] · 65 H 2 O 3a , (NH 2 Me 2 ) 18 (NH 4 ) 6 [Mo 57 V 6 (NO) 6 O 183 (H 2 O) 18 ] · 14 H 2 O 3b and (NH 4 ) 12 [Mo 36 (NO) 4 O 108 (H 2 O) 16 ] · 33 H 2 O 4a ( 3a and 4a were not correctly reported in the literature regarding to their composition, structures and the oxidation states of the metal centres) which contain large isolated anionic species, have been prepared (among them 3a, 3b , and 4a in rather high yield) and characterized by complete crystal structure analysis as well as IR/Raman, UV/VIS/NIR, ESR spectroscopy and magnetic susceptibility measurements, redox titrations, bond valence sum calculations, elemental analyses and thermogravimetric studies. Perspectives for polyoxometalate chemistry referring to the synthesis of “extremely” large nanoscaled species are discussed, together with the occurrence of a large transferable {Mo 17 } building block in the compounds 3a, 3b and 4a which also exists in the corresponding iron compound Na 3 (NH 4 ) 12 [H 15 Mo 57 Fe 6 (NO) 6 O 183 (H 2 O) 18 ] · 76 H 2 O 7a .