Assembly of Polyoxometalate-Based Hybrids with Different Helical Channels upon Subtle Ligand Variation

Self-assembly
of multiple components into well-defined and predictable
structures remains one of the foremost challenges in chemistry. Here,
upon subtle ligand variation, we reported on the assembly of three
new polyoxometalate-based organic–inorganic hybrid compounds
with different helical channel, [Ag3(H2pyttz-I)2]­[PMo12O40] (1), [Ag6(H2pyttz-II)4]­[CoW12O40]·2H2O (2), and [Ag7(Hpyttz-II)3(H2pyttz-II)]­[GeW12O40]·7H2O (3) (H2pyttz-I/II
= 4-/3-pyrid-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl,
POM = polyoxometalates). X-ray diffraction analysis shows that compound 1 is constructed by “butterfly-like” Ag5(H2pyttz-I)2 subunits and POMs clusters,
which are assembled into close helical channels impregnated with the
components selves. Both compounds 2 and 3 are constructed by “paddle-wheel like” Ag4(H2pyttz-II)4 motifs and POMs clusters, which
bring into being the larger helical channels (10.5% and 12.5% of the
cell volume, respectively). Note that the only difference in compounds 2 and 3 is that the former contains 1D metal–organic
chain structure, and the latter contains 2D metal–organic layer
structure. In addition, the photocatalytic degradation of RhB by these
compounds was also investigated.