(Mo2O42+)-O-v directs the formation and subsequent linking of potential building blocks under different boundary conditions: A related set of novel cyclic polyoxomolybdates

dThe synthesis and structural characterization of a novel series of deep-re d mixed-valence (Mo-VI/Mo-V) compounds with nano-sized spherically shaped c luster anions containing 18, 40, or 54 Mo atoms, respectively, is reported: Na-10-[H4Mo18O56(CH3COO)(2)] x ca. 36 H2O x 3 CH3COOH (1), (NH4)(12)Na-12[ Mo40O128] x ca. 70 H2O (2), (NH4)(12)Na-20[H-4-Mo54O168(CH3COO)(4)] x ca. 6 4 H2O (3), Na-32[H4Mo54O168(CH3COO)(4)] x ca. 128 H2O (4), and Na-32[H4Mo54 O168(CH3COO)(4)] x ca. 98 H2O (S). Clusters 3, 4, and 5 differ in the packi ng of the rings in the lattice. The anions are easily formed by reduction o f an acidified aqueous molybdate solution while the deliberately generated (MO2O42+)-O-V group - abundant in all clusters - has a directing influence on the formation of the preliminary building blocks. Furthermore, it is pos sible to control the ratio of the {Mo-2(V)} units to the Mo-VI centres by a djusting the specific concentration of the employed reducing agent.