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We report here a new two-dimensional bimetallic double perovskite with reversible thermochromism, enhanced electrical conductivity and outstanding stability.

Liquid − liquid equilibrium (LLE) data for the water + 2,3-butanediol (2,3-BD) + solvent (n-hexanol or iso-pentanol) ternary systems were obtained at different temperatures (298.2, 308.2, and 318.2...

A new family of isostructural 3d-4f polymetallic complexes, formulated as [Cu(6)Ln(5)(mu(3)-OH)(9) (C4H8O2N)(6)(C5H4ON)(6)(H2O)(9)].(ClO4)(6).(H2O)(22) (Ln = Pr, 1; Nd, 2; Sm, 3; Eu, 4; Gd, 5), was successfully isolated through the simple hydrolysis reaction of 2-aminoisobutyric acid, 2-hydroxypyridine, Cu(CH3COO)(2).H2O, and Ln(ClO4)(3).6H(2)O. Notably, the [Cu(6)Ln(5)] clusters with high molecular symmetry of D3h are rare examples of 2-aminoisobutyric acid-based 3d-4f clusters. The successful theoretical modeling of 5 yielded that the Gd-Gd exchange is of order 0.2 K, whereas the Gd-Cu exchange is an order of magnitude larger. Magnetization data collected for complex 5 yield a magnetic entropy change (-Delta S-m) of 19.6 J kg(-1) K-1 at 3 K and 7 T, which may be attributed to the weak magnetic interactions between the component metal ions. (C) 2020 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Three six-coordinate DyIII single-molecule magnets (SMMs) [Dy(Ot Bu)2 (L)4 ]+ with local D4h symmetry are obtained by optimizing the equatorial ligands. One of the compounds with L=4-phenylpyridine shows an energy barrier (Ueff ) of 2075(11) K, which is the third largest Ueff , and the first Ueff >2000 K for SMMs with axial-type symmetry so far. Ab initio analysis indicates that the exceptional uniaxial magnetic anisotropy is deeply related to the axially compressed octahedral geometry. This work provides a new insight into the local D4h symmetry for high-performance SMMs.

By using a photosensitizer [Ru(bpy)3]2+ as a template, a rare example of a three-dimensional Sn–Se type anionic framework, formulated as {Ru(bpy)3@[Sn4Se9]}n1 (bpy = 2,2′-bipyridine), has been synthesized, and shows evident photocurrent response in the visible light region and related semiconducting behavior.

Here we report two highly emissive perylene diimide (PDI)-based metallacages and explore their complexation with polycyclic aromatic hydrocarbons, such as pyrene, triphenylene, and perylene. The fluorescence quantum yields of metallacages exceed 90% and their binding constants with perylene can reach as high as 2.41 × 104 M-1 in acetonitrile. These features enable further tuning of the emission of the host-guest complexes to obtain white-light emission based on the complementary orange emission of the metallacages and the blue emission of perylene. Moreover, owing to the huge differences of their quantum yields in solution and in the solid state, the host-guest complexes are successfully employed for information encryption. This study offers a general approach for the construction of emissive metallacages and explores their application for information encryption.

Gigantic coordination molecules assembled from a large number of metal ions and organic ligands are structurally and functionally challenging to characterize. Here we show that a heterometallic clu...

Eight-coordinated DyIII centres with D6h symmetry are expected to act as high-performance single-molecule magnets (SMMs) due to the simultaneous fulfilment of magnetic axiality and a high coordination number (a requisite for air stability). But the experimental realization is challenging due to the requirement of six coordinating atoms in the equatorial plane of the hexagonal bipyramid; this is usually too crowded for the central DyIII ion. Here a hexaaza macrocyclic Schiff base ligand and finetuned axial alkoxide/phenol-type ligands are used to show that a family of hexagonal bipyramidal DyIII complexes can be isolated. Among them, three complexes possess nearly perfect D6h local symmetry. The highest effective magnetic reversal barrier is found at 1338(3) K and an open hysteresis temperature of 6 K at the field sweeping rate of 1.2 mT s-1 ; this represents a new record for D6h SMMs.

We report here that energy migration during luminescence can be extremely minimized by caging the fluorescent centers in a molecular cluster of [Tb6(μ3-F)8(piv)10(Hpiv)4DMF]·xDMF·yH2O 1. Experimental and theoretical simulations reveal that bonding terbium with fluoride is the key to reducing the non-radiative multi-phonon relaxation processes, which is disparate to the common hydroxy-based lanthanide clusters.

The detailed analysis of magnetic interactions in a giant molecule is difficult both because the synthesis of such compounds is challenging and the number of energy levels increases exponentially with the magnitude and number of spins. Here, we isolated a {Ni21Gd20} nanocage with a large number of energy levels (≈5 × 1030) and used quantum Monte Carlo (QMC) simulations to perform a detailed analysis of magnetic interactions. Based on magnetization measurements above 2 K, the QMC simulations predicted very weak ferromagnetic interactions that would give a record S = 91 spin ground state. Low-temperature measurements confirm the spin ground state but suggest a more complex picture due to the single ion anisotropy; this has also been modeled using the QMC approach. The high spin and large number of low-lying states lead to a large low-field magnetic entropy (14.1 J kg-1 K-1 for ΔH = 1 T at 1.1 K) for this material., This work was supported by the Natural Science Foundation of China (nos. 21473129, 21620102002, and 21773130), “National Young-1000-Plan” program, State Key Laboratory for Mechanical Behavior of Materials and the Cyrus Chung Ying Tang Foundation.

Nanosized aggregations of metal ions shielded by organic ligands possessing both exquisite structural aesthetics and intriguing properties are fundamentally interesting. Three isostructural gigantic transition-metal-rare-earth heterometallic coordination cages are reported, abbreviated as {Ni64 RE96 } (RE=Gd, Dy, and Y) and obtained by a mixed-ligand approach, each possessing a cuboidal framework made of 160 metal ions and a nanosized spherical cavity in the center. Along with the structural novelty, these hollow cages show highly selective adsorptions for CO2 over CH4 or N2 at ambient temperatures. Moreover, the gadolinium analogue exhibits large magnetocaloric effect at ultralow temperatures.

Fiber-reinforced polymer (FRP) jacketing/wrapping has become an attractive strengthening technique for concrete columns. Wrapping an existing concrete column with continuous FRP jackets with the fiber in the jacket being oriented in the hoop direction is referred to as FRP full wrapping strengthening technique. In practice, however, strengthening concrete columns with vertically discontinuous FRP strips is also favored and this technique is referred to as FRP partial wrapping strengthening technique. Existing research has demonstrated that FRP partial wrapping strengthening technique is a promising and economical alternative to the FRP full wrapping strengthening technique. Although extensive experimental investigations have hitherto been conducted on partially FRP-confined concrete columns, the confinement mechanics of confined concrete in partially FRP-confined circular columns remains unclear. In this paper, an experimental program consisting of fifteen column specimens was conducted and the test results were presented. A reliable three-dimensional (3D) finite element (FE) approach for modeling of partially FRP-confined circular columns was established. In the proposed FE approach, an accurate plastic-damage model for concrete under multiaxial compression is employed. The accuracy of the proposed FE approach was verified by comparisons between the numerical results and the test results. Numerical results from the verified FE approach were then presented to gain an improved understanding of the behavior of confined concrete in partially FRP-confined concrete columns.

Chromium lanthanide heterometallic wheel complexes {Cr8Ln8} (Ln=Gd, Dy and Y) with alternating metal centres are presented. Quantum Monte Carlo simulations reveal antiferromagnetic exchange-coupling constants with an average of 2.1 K within the {Cr8Gd8} wheel, which leads to a large ground spin state (ST=16) that is confirmed by magnetization studies up to 20 Tesla. The {Cr8Dy8} wheel is a single-molecule magnet.