Two 2:2 types of monolanthanide substituted polyoxometalates [{(R-PW 11 O 39 H)Ln(H 2 O) 3 } 2 ] 6-(Ln=Nd III for 1 and Gd III for 2) and [{(R-PW 11 O 39 )Ln(H 2 O)(η 2 ,μ-1,1)-CH 3 COO} 2 ] 10-(Ln=Sm III for 3, Eu III for 4, Gd III for 5, Tb III for 6, Ho III for 7 and Er III for 8) have been synthesized in aqueous solution and characterized by elemental analyses, IR spectra, UV-vis-NIR spectra, thermogravimatric analyses and single-crystal X-ray diffraction. The common structural features are that they are constructed from monovacant Keggin-type polyoxoanions [R-PW 11 O 39 ] 7and trivalent lanthanide cations. Both 1 and 2 are essentially isomorphous, and the molecular structure is built by two symmetrically related monolanthanide substituted Keggin units [R-PW 11 O 39 Ln(H 2 O) 3 ] 4linked via two Ln-O-W bridges, representing the first monovacant Keggin polyoxotungstate dimers constituted by two [R-PW 11 O 39 ] 7polyoxoanions and two lanthanide cations in polyoxometalate chemistry. 3-8 are also isostructural and display another dimeric structure constructed from two monolanthanide substituted units [(R-PW 11 O 39 )Ln(H 2 O)(η 2 ,μ-1,1)-CH 3 COO] 5bridged by two (η 2 ,μ-1,1)-acetato ligands. The photoluminescence properties of 4 and 6 were investigated at room temperature. Magnetic susceptibility measurements of 1, 3, 4, 7 and 8 between 2 and 300 K exhibit that their magnetic behaviors mainly result from the spin-orbital coupling interactions as well as weak antiferromagnetic exchange interactions within magnetic centers. The electrochemical properties of 1, 3, 4, 5, 7 and 8 were studied by means of cyclic voltammetry in aqueous solution with 0.5 M Na 2 SO 4 as supporting electrolyte.

A series of organic–inorganic hybrid polyoxometalate derivatives {[Cu(en)2]1.5[Cu(en)(2,2′-bipy)(H2O) n ]Ce[(α-PW11O39)2]}6– [(Ln, n) = (CeIII, 0) for 1, (PrIII, 1) for 2)], {[Cu(en)2]2(H2O)[Cu(en)(2,2′-bipy)]Ln[(α-HPW11O39)2]}4– [Ln = GdIII for 3, TbIII for 4, ErIII for 5] and {[Cu(en)2]1.5[Cu(en)(2,2′-bipy)]Nd[(α-H5PW11O39)2]}3– for 6 (2,2′-bipy =2,2′-bipyridine and en = ethylenediamine) have been successfully synthesized under hydrothermal conditions and further characterized by elemental analyses, inductively coupled plasma (ICP) analyses, X-ray powder diffraction (XRPD), IR spectra, UV spectra, electron paramagnetic resonance (EPR) spectra, thermogravimetric (TG) analyses, and single-crystal X-ray diffraction. The common features of 1–6 are that they all consist of sandwich-type [Ln(α-PW11O39)2]11– polyoxoanions as the fundamental building blocks and copper coordination cations as bridges. 1 and 2 show the 1-D zigzag chains, and 3–5 exhibit the unprecedented 2-D structures built by [Ln(α-PW11O39)2]11– polyoxoanions and [Cu(en)2]2+ and [Cu(en)(2,2′-bpy)]2+ cations, whereas 6 displays the scarce 3-D framework with a (46·64) topology. As expected, 1–6 contain two types of organic ligands. Furthermore, the photocatalysis properties of rhodamine-B (RhB) upon a 500 W Hg lamp irradiation in the presence of 1, 2, 3, 4, 5, or 6 have been examined. The photoluminescence property of 4 has been investigated.

A series of organic−inorganic hybrid lacunary Keggin silicotungstate 3d-4f heterometallic derivatives, {[Cu (en) 2 ] 1.5 Ln[(α-SiW 11 O 39 ) 2 ]} 2 20− [Ln = Gd III for 1, Tb III for 2, Dy III for 3, Er III for 4, III , 2, 7) for 8, (Sm III , 3, 5) for 9] (en = ethylenediamine) have been successfully synthesized under hydrothermal conditions and further characterized by elemental analyses, inductively coupled plasma atomic emission spectrometry (ICP-AES) analyses, X-ray powder diffraction (XRPD), IR spectra, thermogravimetric (TG) analyses, and singlecrystal X-ray diffraction. The common features of 1−5 and 8−9 are that they all consist of a sandwich-type [Ln(α-SiW 11 O 39 ) 2 ] 13− polyoxoanion, whereas both 6 and 7 consist of the unusual 1:1 [Ln(α-SiW 11 O 39 )] 5− units and [Cu(en) 2 ] 2+ coordination cations. 1−5 show dimeric structures, and 6−9 display unprecedented three-dimensional (3D) frameworks, representing the first 3D 3d-4f heterometallic silicotungstates. The features of 6 and 7 are that the components are closely packed along the 2 1 screw axis to generate scarce 5-connected network structures with the Schlafli symbol of (4 8 •6 2 ), while 8 and 9 exhibit the 4-connected (6 6 ) topology and 6-connected (4 8 •5 4 •6 3 ) topology structures, respectively. Furthermore, 2, 3, and 9 manifest apparent fluorescence signals, which can be assigned to the characteristic emissions of Tb III , Dy III , and Sm III cations, respectively.

Four organic-inorganic hybrid monolacunary Keggin polyoxotungstate-based 3d-4f heterometallic derivatives [Cu(en) 2 (H 2 O)] 2 [Tb(a-HSiW 11 O 39 )(H 2 O) 3 ]?12H 2 O (1), [Cu(en) 2 (H 2 O)] 2 [Eu(a-HGeW 11 O 39 ) (H 2 O) 3 ]?12H 2 O (2), Na 2 [Cu(en) 2 (H 2 O)] 4 [Sm(a-PW 11 O 39 )(CH 3 COO)(H 2 O)] 2 ?10H 2 O (3) and [Cu(en) 2 (H 2 O)] 5 [Cu(en) 2 ][Tb(a-GeW 11 O 39 )(CH 3 COO)(H 2 O)] 2 ?14H 2 O (4) (en = ethylenediamine) have been hydrothermally prepared and characterized by elemental analyses, IR spectra, thermogravimetric (TG) analyses and X-ray single-crystal diffraction. 1 and 2 are isomorphic and exhibit the interesting one-dimensional chain arrangements built by monovacant-lanthanide substituted Keggin-type [Ln(a-HXW 11 O 39 )(H 2 O) 3 ] 42 (Ln = Tb III , Eu III ; X = Si IV , Ge IV ) units via W-O-Ln-O-W bridges whereas 3 and 4 display typical organicinorganic hybrid dimeric structures consisting of [(a-XW 11 O 39 )Ln(H 2 O)(g 2 ,m-1,1)-CH 3 COO] 2 10/122 units modified by [Cu(en) 2 (H 2 O)] 2+ fragments. To the best of our knowledge, 1 and 2 represent the rare 1Dchain-like monovacant Keggin-type 3d-4f heterometallic polyoxotungstates containing both unusual 1 : 1[Ln(a-XW 11 O 39 )] 4/52 units and en ligands, whereas 3 and 4 represent the first monovacant Keggin-type phosphotungstates or germanotungstates containing both 3d-4f heterometals and mixed ligands of en and acetate. Furthermore, the variable-temperature magnetic susceptibilities of 1 and 3 have been investigated.

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Two new copper-phosphotungstate complexes [Cu II (1,3-dap) 2 ] 2 [Cu II (1,3-dap)] 2 H[-PW 10.5 Cu II 1:5 O 40 ] (1) and [Cu I (phen) 2 ] 3 [-PW 12 O 40 ](2) (1,3-dap ¼ 1,3-diaminopropane, phen ¼ 1,10-phenanthroline) have been synthesized and characterized by elemental analyses, IR spectroscopy, UV spectroscopy, thermogravimetric analyses, fluorescence spectroscopy, X-ray photoelectron spectroscopy, and single-crystal X-ray diffraction. Single-crystal diffraction analyses indicate that both 1 and 2 consist of a saturated -Keggin phosphotungstate fundamental building unit as polyoxoanions and several metal-organic moieties as countercations. In 1, two [Cu(1,3-dap)] 2þ complex cations are capped on the polyoxoanion [PW 10.5 Cu II 1:5 O 40 ] 9À through four bridging oxygens and the other two [Cu(1,3-dap) 2 ] 2þ coordination cations are grafted on the terminal oxygens of the polyoxoanion, whereas in 2, three [Cu(phen) 2 ] 2þ complex cations are discrete. Fluorescence reveals that 2 exhibits a broad emission band at 437 nm upon excitation at 380 nm.

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