Molecular Growth of Polyoxometalate Architectures Based on [−Ag{Mo₈}Ag−] Synthons: Toward Designed Cluster Assemblies

The interaction of silver(I) cations with octamolybdate [Mo8O26]4− has been investigated by applying the principles of the building-block concept to the well established silver−octamolybdate reaction system. The self-assembly of dimeric {Ag2} linkers allows the formation and isolation of chains and networks where [Mo8O26]4− clusters are cross-linked by silver(I) cations. The influence of the solvent on the overall topology has been studied, and the role of the counterion on the resulting structure has been highlighted in each assembly. Fine-tuning of the metal−metal distances of the dimeric {Ag2} linking units has been achieved by using different coordinating solvents which act as bridges. Five compounds based on silver octamolybdate building blocks have been isolated, including an uncommon intermediate ((Ph4P)2[Ag2(CH3CN)2(Mo8O26)]), three one-dimensional polymeric chains ([Ag(C7H12O2N)(CH3CN)]2n[Ag2(CH3CN)2(Mo8O26)]n·2CH3CN, (Ph4P)2n[Ag2(DMF)2(Mo8O26)]n·2DMF, and (H2NMe2)2n[Ag2(DMF)2(Mo8O26)]n·2DMF), and a two-dimensional cross-linked network ([(Ag(DMF))2(Ag(DMF)2)2Mo8O26]n). Each compound has been characterized by single-crystal X-ray diffraction, elemental analysis, and FT-IR.