Evans-Showell-Type Polyoxometalates Constructing High-Dimensional Inorganic-Organic Hybrid Compounds with Copper-Organic Coordination Complexes: Synthesis and Oxidation Catalysis.

Four new hybrid architectures containing a [Co2 Mo10 H4 O38 ]6- polyoxoanion, (en)[Cu3 (ptz)4 (H2 O)4 ][Co2 Mo10 H4 O38 ]·24H2 O (1), (Hbim)2 [{Cu(bim)2 (H2 O)2 }2 {Co2 Mo10 H4 O38 }]·5H2 O (2), H2 [Cu(dpdo)3 (H2 O)4 ][{Cu2 (dpdo)3 (H2 O)4 (CH3 CN)}2 {Co2 Mo10 H4 O38 }2 ]·9H2 O (3), and (H2 bpp)4 [{Cu(H2 O)2 }{NaCo2 Mo10 H4 O38 }2 ]·10H2 O (4), where ptz = 5-(4-pyridyl)-1H-tetrazole, en = ethylenediamine, bim = benzimidazole, dpdo = 4,4'-bipyridine-N,N'-dioxide, and bpp = 1,3-bis(4-pyridyl)propane, have been prepared and characterized through elemental analysis, thermogravimetric analysis, IR spectroscopy, and powder and single-crystal X-ray diffraction. Compound 1 shows a 3D host-guest framework composed of 3D Cu-ptz as the host and Evans-Showell-type polyoxoanion [Co2 Mo10 H4 O38 ]6- as the guest. Compound 2 is constructed from [Co2 Mo10 H4 O38 ]6- polyoxoanions and Cu-bim coordination complexes to form a 2D covalent layer. Compound 3 also exhibits a 2D hybrid network based on [Co2 Mo10 H4 O38 ]6- polyoxoanions linked by Cu-dpdo coordination groups. Compound 4 is a 1D double-chain structure composed of [Co2 Mo10 H4 O38 ]6- polyoxoanions joined together by Na+ and Cu2+ cations. As far as we know, compound 1 is the first host-guest compound with an Evans-Showell-type polyoxometalate as the guest, and compounds 2 and 3 are the first 2D inorganic-organic hybrid architectures constructed from Evans-Showell-type polyoxometalates. Compounds 1-4 are redox catalysts that heterogeneously prompt sulfide and alcohol oxidation with excellent efficiency.