Two Unprecedented POM-Based Inorganic–Organic Hybrids with Concomitant Heteropolytungstate and Molybdate

Two
novel POM-based inorganic–organic hybrids, [Cu6II(2,2′-bipy)6(Mo6O22)­(SiW12O40)]n (1), and {[Cu6II(ppz)6(H2O)5(MoO4)­(SiW12O40)]·4H2O}n (2) (2,2′-bipy = 2,2′-bipyridine, Hppz = 3-(pyrid-2-yl)­pyrazole),
have been constructed from heteropolytungstates and molybdates. Two
compounds have been identified by single crystal X-ray diffraction,
elemental analysis, and FT-IR. Compound 1 shows a 1D
(one-dimensional) chain structure constructed from classical Keggin
heteropolytungstate [SiW12O40]4– clusters and [Cu6(2,2′-bipy)6] modified
isopolymolybdates [Mo6O22]8–. Compound 2 also represents a 1D chain-like motif built
from classical Keggin heteropolytungstate [SiW12O40]4– clusters and [Cu8(ppz)6(H2O)5] modified molybdates MoO42–. Compound 1 represents the first
example of POM-based inorganic–organic hybrid with mixed heteropolytungstates
and isopolymolybdates. ESI-MS (electrospray ionization mass spectrometry)
technique was employed to reveal the species and their evolutions
in the hydrothermal reaction, whereby trivacant [SiW9]
building block gradually transforms to classical Keggin [SiW12] during assembly process. Furthermore, the electrocatalytic and
magnetic properties were discussed in details.