MoV2O42+ Directs the Formation and Subsequent Linking of Potential Building Blocks under Different Boundary Conditions: A Related Set of Novel Cyclic Polyoxomolybdates

Abstract

The synthesis and structural characterization of a novel series of deep-red mixed-valence (MoVI/MoV) compounds with nano-sized spherically shaped cluster anions containing 18, 40, or 54 Mo atoms, respectively, is reported: Na10[H4Mo18O56(CH3COO)2] × ca. 36 H2O × 3 CH3COOH (1), (NH4)12Na12[Mo40O128] × ca. 70 H2O (2), (NH4)12Na20[H4Mo54O168(CH3COO)4] × ca. 64 H2O (3), Na32[H4Mo54O168(CH3COO)4] × ca. 128 H2O (4), and Na32[H4Mo54O168(CH3COO)4] × ca. 98 H2O (5). Clusters 3, 4, and 5 differ in the packing of the rings in the lattice. The anions are easily formed by reduction of an acidified aqueous molybdate solution while the deliberately generated MoV2O42+ group − abundant in all clusters − has a directing influence on the formation of the preliminary building blocks. Furthermore, it is possible to control the ratio of the {MoV2} units to the MoVI centres by adjusting the specific concentration of the employed reducing agent.