An inorganic-organic hybrid MnIII{Mn}2 cluster consisting of rare Lindqvist-like Mn6 subunits with high proton conductivity

A Heniconuclear {Mn21} Cluster-Based Coordination Polymer with Manganese(II) Linkers Showing High Proton Conductivity

An unprecedented metal-linked cluster-based coordination polymer, composed of heniconuclear {Mn₂₁} clusters and Mn(II) ions as the nodes and linkers, respectively, was self-assembled from a facile aqueous synthesis. The structural analysis reveals that the compound possesses a rare 3D 8-connected hex framework topology. Significantly, the compound demonstrates a high proton conductivity of 1.06 mS cm^-1 at 373 K and 98% RH and exhibits a magnetocaloric effect with a magnetic entropy change of -9.94 J kg^-1 K^-1 at H = 80 kOe and T = 6.0 K.

Proton transfer in polyamine-P2Mo5 model adducts: exploring the effect of polyamine cations on their proton conductivity

Constructing acid-base pairs is one of the efficient strategies for the design of proton conductors with high conductivity, due to the ultrafast proton-hopping with a low energy barrier between a proton donor (acid group) and an acceptor (base group). In this study, an acid-base adduct polyamine-P₂Mo₅ model system was established, including adducts [C₆N₄H₂₂][H₂P₂Mo₅O₂₃]·H₂O (P₂Mo₅-TETA), [C₄N₃H₁₆]₂[P₂Mo₅O₂₃]·H₂O (P₂Mo₅-DETA), and [C₂N₂H₁₀]₂[H₂P₂Mo₅O₂₃] (P₂Mo₅-EN), (TETA = triethylenetetramine, DETA = diethylenetriamine, EN = ethanediamine). Proton conductivity analyses showed that adduct P₂Mo₅-EN exhibited the highest proton conductivity 1.13 × 10^-2 S cm^-1 at 65 °C and 95% RH, which was one and three orders of magnitude greater than those of P₂Mo₅-DETA and P₂Mo₅-TETA under the same conditions. E_a values of all three adducts are lower than 0.4 eV, which indicates that their proton transfer is attributed to the Grotthuss mechanism. Combined with visual structure analysis, the proton transport pathways of three adducts are highlighted. Moreover, we use this model system to discuss in detail the effect of pK_a, proton density and size of polyamine molecules on the proton conductivity of organic amine-POM adducts.

Two 3D Mn-based coordination polymers: synthesis, structure and magnetocaloric effect

Two three-dimensional (3D) coordination polymers, namely MnII 6(CH3COO)2(HCOO)2(IN)8(C4H8O)2(H2O) and MnIII 6MnII 12(μ3-O)6(CH3COO)12(IN)18(H2O)7.5 (abbreviated as Mn II 6 and Mn II 12 Mn III 6 respectively; HIN = isonicotinic acid), were synthesized by the reaction of Mn(CH3COO)2·4H2O and isonicotinic acid under solvothermal conditions. Magnetic studies revealed that antiferromagnetic interactions may be present in compounds Mn II 6 and Mn II 12 Mn III 6 . Moreover, the values of -ΔS m (26.27 (Mn II 6 ) and 37.69 (Mn II 12 Mn III 6 ) J kg-1 K-1 at ΔH = 7 T) are relatively larger than those of the reported Mn-based coordination polymers. This work provides a great scope in the magnetocaloric effect (MCE) of pure 3d-type systems.

{VMo9O31[RC(CH2O)3]}6−: the first class of triol ligand covalently-decorated Keggin-type polyoxomolybdates

The first class of triol-ligand covalently-decorated Keggin-type polyoxomolybdates through C–O–Mo bonds were obtained and characterized.