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With the rapid development of science and technology and the trend of multidisciplinary pervasion, POM-based TM-RE heterometallic chemistry (POM = polyoxometalate, TM = transition-metal, RE = rare-earth) has become one of the most rapidly growing and challengeable areas of inorganic chemistry due to the impressive structural diversities, various chemical compositions and potential applications of these materials in magnetism, optics, electrochemistry, electrocatalysis and materials science. Over the past several years, continuous interest and persisting efforts have been dedicated to the preparation and exploration of POM-based TM-RE heterometallic derived materials (PTRHDMs), which have led to more than two hundred PTRHDMs. In this review, we summarize the structural types of reported PTRHDMs together with synthetic strategies, structural motifs and relevant functional applications. The exciting array of this emerging research theme presages continuous growth and great vitality. In the last section, some prospects of this branch are also presented and possible guidance for future work is outlined.

Engineering the band gap chemically by organic molecules is a powerful tool with which to optimize the properties of inorganic 2D materials. The obtained materials are however still limited by inhomogeneous compositions and properties at nanoscale and small adjustable band gap ranges. To overcome these problems in the traditional exfoliation and then organic modification strategy, an organic modification and then exfoliation strategy was explored in this work for preparing 2D organic metal chalcogenides (OMCs). Unlike the reported organically modified 2D materials, the inorganic layers of OMCs are fully covered by long-range ordered organic functional groups. By changing the electron-donating ability of the organic functional groups and the electronegativity of the metals, the band gaps of OMCs were varied by 0.83 eV and their conductivities were modulated by 9 orders of magnitude, which are 2 and 10 7 times higher than the highest values observed in the reported chemical methods, respectively.

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By the routine aqueous solution method, a series of transitionmetal−lanthanide heterometallic tungstoantimonates [Ln(H 2 O) 8 ] 2 -[Fe 4 (H 2 O) 8 (thr) 2 ][B-β-SbW 9 O 33 ] 2 ·22H 2 O [Ln = Pr III (1), Nd III (2), Sm III (3), Eu III (4), Gd III (5), Dy III (6), Lu III (7), thr = threonine] were prepared and structurally characterized by multiple testing techniques. The common structural characteristic of 1−7 is that they are isomorphous and all consist of a [Fe 4 (H 2 O) 8 (thr) 2 (B-β-SbW 9 O 33 ) 2 ] 6− subunit with two supporting [Ln(H 2 O) 8 ] 3+ cations on both sides. It should be pointed out that two thr ligands in the [Fe 4 (H 2 O) 8 (thr) 2 (B-β-SbW 9 O 33 ) 2 ] 6− subunit substitute for two water ligands in the classical [Fe 4 (H 2 O) 10 (B-β-SbW 9 O 33 ) 2 ] 6− polyoxoanion. As far as we know, 1−7 represents the first organic−inorganic tungstoantimonate hybrids consisting of transition metal and lanthanide cations and amino acid components. The fluorescence behavior of 4 has been measured and manifests the remarkable fluorescence feature resulting from the emission signature of Eu III cations. Furthermore, the solid-state electrochemistry and electrocatalytic performances of 1 have been measured in 0.5 mol L −1 Na 2 SO 4 +H 2 SO 4 aqueous solution, and the results show that 1 illustrates comparatively apparent catalytic activities toward the BrO 3 − and H 2 O 2 reduction. The magnetic properties of 3 and 6 have been studied. ■ INTRODUCTION Polyoxometalates (POMs) represent an special family of intriguing metal−oxygen cluster compounds formed by high oxidation state early transition metals (preferably Mo, W, V, and Nb) bearing tremendous diverse structures, seductive properties, and latent applications in catalysis, magnetism, electronics, photoluminescence, pharmaceutical, and materials science. 1−9 Highly negative charge, O-enriched lacunary POMs, can act as one kind of outstanding multidentate nucleophilic candidates to coordinate to transition-metal (TM) or lanthanoid (Ln) ions to construct neoteric TM or Ln encapsulated POM aggregates with varying metal centers, alluring topological architectures and novel properties, which can also make more magnetic or catalytic components implant to the POM cluster skeletons. Therefore, the exploration and discovery of TM-or Ln-functionalized POMs have attracted considerable interest over the past few decades. Hitherto, a vast amount of TM-or Ln-substituted POMs have been sequentially discovered. 10−19 In contrast, explorations on POM-based TM−Ln heterometallic derivatives (PTLHDs) still remain less developed, although their unmatched diversities and physicochemical properties entail them to become candidates for magnetic materials or optical sensing materials. 20−22 Less work dedicated to PTLHDs mainly lies in an inescapable competing reaction between electrophilic Ln and TM cations with nucleophilic POM precursors within a system. 23 Therefore, the search and preparation of POMbased TM−Ln heterometallic materials will remain a longstanding and persisting chall...

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