Polyoxometalate-Induced New Self-Assemblies Based on Copper Ions and Bichelate-Bridging Ligands

The
introduction of polyoxometalates (POMs) into the metal–organic
complex synthetic system containing copper ions and bichelate-bridging
ligands (bis­(3-(2-pyridyl)­pyrazole-1-ylmethyl)­benzene, bppmb) led
to the isolation of three new organic–inorganic hybrid compounds
[CuIILo]2H­[BW12O40]·4H2O (1), [CuILo]4[SiW12O40]·5H2O (2), and [CuLp]3H2[BW12O40]·5H2O
(3) (Lo = 1,2-bppmb and Lp = 1,4-bppmb). All three compounds were hydrothermally synthesized
and characterized by elemental analyses, IR spectra, TG analyses,
powder X-ray diffraction, and single-crystal X-ray diffraction analyses.
In these compounds, the use of Keggin-type POMs induces the formation
of a series of new metal–organic secondary building units based
on the copper ions and bppmb ligands such as helical chain and chiral
Möbius Strip, which further form interesting supramolecular
self-assemblies with the polyoxoanions. The degradation of Rhodamine-B
(RhB) under UV irradiation with compounds 1–3 as the heterogeneous photocatalysts was investigated, and
these compounds show good photocatalytic properties for RhB degradation.