Controllable growth of chains and grids from polyoxomolybdate building blocks linked by silver(I) dimers

Molecular growth processes utilizing a beta-octamolybdate synthon and {Ag-2} dimers are described and the directing influence of "encapsulating" cations and coordinating solvent is also demonstrated. The growth of two ID chains, (nBu(4)N)(2n)[Ag2Mo8O26], (1) and (nBu(4)N)(2n)[Ag2Mo8O26(CH3CN)(2)](n) (2), is achieved when nBu(4)N(+) ions are used, and the diameter of the chains can be expanded by the coordination of CH3CN solvent (2). The formation of a type of gridlike structure in which ID chains are crossed-over each other in alternatively packed layers is achieved in DMSO as the solvent; DMSO acts as a linking group to give (nBu(4)N)(2n)[Ag2Mo8O26(dmso)(2)](n) (3), which, similar to I and 2, still incorporates the BU4N+ ions that exert an "encapsulating" influence. However, in (HDMF)(n)[Ag-3(Mo8O26)(dmf)(4)](n) (4) the relatively bulky Bu4N+ ions are exchanged for protonated DMF cations, thereby allowing the chains to condense to a 2D array. The building block concept is further enforced by the isolation of a "monomeric" unit (Ph4P)(2)[Ag2Mo8O26(dmso)(4)] (5), which is isolated when the Ph4P+ ions are so "encapsulating" as to prevent aggregation of the {Ag-Mo-8-Ag} building blocks. The nature of the (AgAg)-Ag-... dimers in each of the compounds 1-4 is examined by DFT calculations and the interplay between these Ag-Ag interactions and the structure types is described.