Secondary spacer modulated assembly of polyoxometalate based metal-organic frameworks

To investigate the influence of a secondary spacer on the resulting structures of POMOFs containing pytz, five new compounds with different dimensionalities, [Cu-5(2-pytz)(6)(H2O)(4)][SiMo12O40]center dot 3H(2)O (1), [Cu-3(2-pytz)(4)bipy][H2SiMo12O40]center dot bipy (2), [Cu-3(2-pytz)(2)(bipy)(4)(H2O)(6)][H4SiW12O40](2)center dot 6H(2)O (3), [Cu-2(2-pytz)(phen)(OH)](2)[SiW12O40]center dot H2O (4), [Cu-3(4-pytz)(4)(H2O)(4)][H2SiW12O40]center dot 2H(2)O (5), were synthesized. When only 2-pytz was employed, compound 1 with a 3D framework was obtained, whereas when the secondary spacers (4,4'-bipy, phen and 4-pytz) were introduced into the reaction system of 1, compounds 2-5 were obtained and exhibit a broad range of structures, including 0D, 1D, 2D and 3D frameworks. It can be observed from the architectures of compounds 1-5 that the secondary spacers have a great effect on the structures of the MOFs, which results in the formation of various dimensional POMOF compounds. Additionally, photocatalytic experiments of 1-5 for the photocatalytic degradation of RhB under UV irradiation were also investigated.