A Family of Binuclear Dysprosium(III) Radical Compounds with Magnetic Relaxation in ON and OFF States

Four binuclear dysprosium compounds incorporating the radical ligand 2-(4-oxidopyridyl)-4,4,5,5-tetramethylimidazolin-1-oxyl-3-oxide (PyNONIT) have been successfully synthesized under appropriate conditions. Centrosymmetric bimetallic Dy₂O₂ cores in all of the compounds through double-μ₂-oxygen atoms of the <i>N</i>-oxide groups are realized in a metal–radical approach for the first time. Dimers <b>1</b> and <b>2</b>, of the same formula {[Dy­(hfac)₃(PyNONIT)]₂}₂ (hfac = hexafluoroacetylacetonate) but obtained by different methods, which contain almost identical local symmetry of <i>D</i>_4<i>d</i> and Dy–(O)₂–Dy bridging fashion, however, display no out-of-phase alternating-current (ac) signal for <b>1</b> and slow relaxation of the magnetization for <b>2</b> corresponding to the difference of the crystal packing mode. The adduct ([Dy­(hfac)₃(PyNONIT)]₂[Dy_0.5(hfac)_1.5(H₂O)]₂) (<b>3</b>) consists of two items, the dimer [Dy­(hfac)₃(PyNONIT)]₂ and the monomer [Dy­(hfac)₃(H₂O)₂], where the symmetry of Dy^III ion in Dy₂O₂ decreases to <i>D</i>_2<i>d</i>, showing slow relaxation of the magnetization at lower temperature. Interestingly, a moisture-mediated reversible solid transformation between <b>1</b> and ([Dy­(hfac)₃(H₂O)­(PyNONIT)]₂) (<b>4</b>) has been investigated. Spongelike <b>1</b> can undergo a transition from eight to nine coordination at room temperature through hydration. A different coordination field is mostly responsible for no ac signal noticed for <b>4</b>. The structural diversity of the Dy₂ family provides an opportunity to expand the investigation on 4f single-molecule magnets. Approaches that the relaxation of the supramolecular dimer can be tuned to ON and OFF states modulated by the packing mode and ligand field are presented

A Family of Binuclear Dysprosium(III) Radical Compounds with Magnetic Relaxation in ON and OFF States

Four binuclear dysprosium compounds incorporating the radical ligand 2-(4-oxidopyridyl)-4,4,5,5-tetramethylimidazolin-1-oxyl-3-oxide (PyNONIT) have been successfully synthesized under appropriate conditions. Centrosymmetric bimetallic Dy₂O₂ cores in all of the compounds through double-μ₂-oxygen atoms of the <i>N</i>-oxide groups are realized in a metal–radical approach for the first time. Dimers <b>1</b> and <b>2</b>, of the same formula {[Dy­(hfac)₃(PyNONIT)]₂}₂ (hfac = hexafluoroacetylacetonate) but obtained by different methods, which contain almost identical local symmetry of <i>D</i>_4<i>d</i> and Dy–(O)₂–Dy bridging fashion, however, display no out-of-phase alternating-current (ac) signal for <b>1</b> and slow relaxation of the magnetization for <b>2</b> corresponding to the difference of the crystal packing mode. The adduct ([Dy­(hfac)₃(PyNONIT)]₂[Dy_0.5(hfac)_1.5(H₂O)]₂) (<b>3</b>) consists of two items, the dimer [Dy­(hfac)₃(PyNONIT)]₂ and the monomer [Dy­(hfac)₃(H₂O)₂], where the symmetry of Dy^III ion in Dy₂O₂ decreases to <i>D</i>_2<i>d</i>, showing slow relaxation of the magnetization at lower temperature. Interestingly, a moisture-mediated reversible solid transformation between <b>1</b> and ([Dy­(hfac)₃(H₂O)­(PyNONIT)]₂) (<b>4</b>) has been investigated. Spongelike <b>1</b> can undergo a transition from eight to nine coordination at room temperature through hydration. A different coordination field is mostly responsible for no ac signal noticed for <b>4</b>. The structural diversity of the Dy₂ family provides an opportunity to expand the investigation on 4f single-molecule magnets. Approaches that the relaxation of the supramolecular dimer can be tuned to ON and OFF states modulated by the packing mode and ligand field are presented

MoS₂/CdS Nanosheets-on-Nanorod Heterostructure for Highly Efficient Photocatalytic H₂ Generation under Visible Light Irradiation

Semiconductor-based photocatalytic H₂ generation as a direct approach of converting solar energy to fuel is attractive for tackling the global energy and environmental issues but still suffers from low efficiency. Here, we report a MoS₂/CdS nanohybrid as a noble-metal-free efficient visible-light driven photocatalyst, which has the unique nanosheets-on-nanorod heterostructure with partially crystalline MoS₂ nanosheets intimately but discretely growing on single-crystalline CdS nanorod. This heterostructure not only facilitates the charge separation and transfer owing to the formed heterojunction, shorter radial transfer path, and fewer defects in single-crystalline nanorod, thus effectively reducing the charge recombination, but also provides plenty of active sites for hydrogen evolution reaction due to partially crystalline structure of MoS₂ as well as enough room for hole extraction. As a result, the MoS₂/CdS nanosheets-on-nanorod exhibits a state-of-the-art H₂ evolution rate of 49.80 mmol g^–1 h^–1 and an apparent quantum yield of 41.37% at 420 nm, which is the advanced performance among all MoS₂/CdS composites and CdS/noble metal photocatalysts. These findings will open opportunities for developing low-cost efficient photocatalysts for water splitting

Lanthanide Germanate Cluster Organic Frameworks Based on {Ln₈Ge₁₂} Clusters: From One-Dimensional Chains to Two-Dimensional Layers and Three-Dimensional Frameworks

Under hydrothermal conditions, six series of novel lanthanide (Ln) organogermanates (LnGs) [Ln₈Ge₁₂(μ₃-O)₂₄E₁₂­(H₂O)₁₆]­·14H₂O (Ln³⁺ = Pr³⁺, <b>1</b>; Nd³⁺, <b>2</b>; Sm³⁺, <b>3</b>; Eu³⁺, <b>4</b>; Gd³⁺, <b>5</b>; one-dimensional (1-D) LnG cluster organic chain (LnGCOC)), {[Nd₈Ge₁₂­(μ₃-O)₂₄­E₁₂(H₂O)₁₀]­(μ₂-H₂O)₂­[Nd₈Ge₁₂­(μ₃-O)₂₄­E₁₂(H₂O)₁₆]}­·18H₂O (<b>6</b>, two-dimensional (2-D) planar LnG cluster organic layer (LnGCOL)), {[Ln₂GeE­(HO)₂O­(H₂O)­(CH₃COO)₂­(CO₃)]₂­[Ln₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₁₀]}­·6H₂O (Ln³⁺ = Pr³⁺, <b>7</b>; Nd³⁺, <b>8</b>; 2-D wave-shaped LnGCOL), [TbGeE­(HO)₂O­(H₂O)­(pca)]₂­[Tb₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₈]·10H₂O (<b>9</b>, three-dimensional (3-D) LnG cluster organic framework (LnGCOF)), {([Nd­(pza)₂­(H₂O)₂]₂­[Nd₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₁₂])­([Nd­(pza)₂]₂­[Nd₈Ge₁₂E₁₂­(Hpza)₂­(μ₃-O)₂₄­(H₂O)₁₀])}­·4OH­·14H₂O (<b>10</b>, 3-D LnGCOF), {[Nd₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₁₀]­[Nd­(pca)­(pda)­(H₂O)]₂}­·12H₂O (<b>11</b>, 3-D LnGCOF) and {[Nd₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₁₀]­[Nd­(pza)­(pda)­(H₂O)]₂}­·12H₂O (<b>12</b>, 3-D LnGCOF) (Hpca = 2-picolinic acid, H₂pda = 2,6-pyridinedicarboxylic acid, Hpza = 2-pyrazinecarboxylic acid) were prepared by introducing the second auxiliary ligands into the organogermanate–lanthanide–oxide reaction system. The obtainment of these LnGs realized the utilization of the second auxiliary ligands inducing the assembly from 1-D LnGCOCs to 2-D LnGCOLs and 3-D LnGCOFs based on LnG cluster (LnGC) {Ln₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₁₆}­({Ln₈Ge₁₂}) units and Ln–organic complexes or organic ligand connectors. It should be noted that the well-organized structural constructions of <b>1</b>–<b>12</b> can be visualized as the gradual replacement of active water sites located at equatorial and polar positions on the hypothetical [Ln₈Ge₁₂­(μ₃-O)₂₄­E₁₂(H₂O)₁₈] LnGC core with oxygen or nitrogen atoms from organic ligands. The solid-state luminescent properties of <b>2</b>, <b>3</b>, <b>4</b>, <b>6</b>, and <b>8</b>–<b>12</b> have been investigated at room temperature

Lanthanide Germanate Cluster Organic Frameworks Based on {Ln₈Ge₁₂} Clusters: From One-Dimensional Chains to Two-Dimensional Layers and Three-Dimensional Frameworks

Under hydrothermal conditions, six series of novel lanthanide (Ln) organogermanates (LnGs) [Ln₈Ge₁₂(μ₃-O)₂₄E₁₂­(H₂O)₁₆]­·14H₂O (Ln³⁺ = Pr³⁺, <b>1</b>; Nd³⁺, <b>2</b>; Sm³⁺, <b>3</b>; Eu³⁺, <b>4</b>; Gd³⁺, <b>5</b>; one-dimensional (1-D) LnG cluster organic chain (LnGCOC)), {[Nd₈Ge₁₂­(μ₃-O)₂₄­E₁₂(H₂O)₁₀]­(μ₂-H₂O)₂­[Nd₈Ge₁₂­(μ₃-O)₂₄­E₁₂(H₂O)₁₆]}­·18H₂O (<b>6</b>, two-dimensional (2-D) planar LnG cluster organic layer (LnGCOL)), {[Ln₂GeE­(HO)₂O­(H₂O)­(CH₃COO)₂­(CO₃)]₂­[Ln₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₁₀]}­·6H₂O (Ln³⁺ = Pr³⁺, <b>7</b>; Nd³⁺, <b>8</b>; 2-D wave-shaped LnGCOL), [TbGeE­(HO)₂O­(H₂O)­(pca)]₂­[Tb₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₈]·10H₂O (<b>9</b>, three-dimensional (3-D) LnG cluster organic framework (LnGCOF)), {([Nd­(pza)₂­(H₂O)₂]₂­[Nd₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₁₂])­([Nd­(pza)₂]₂­[Nd₈Ge₁₂E₁₂­(Hpza)₂­(μ₃-O)₂₄­(H₂O)₁₀])}­·4OH­·14H₂O (<b>10</b>, 3-D LnGCOF), {[Nd₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₁₀]­[Nd­(pca)­(pda)­(H₂O)]₂}­·12H₂O (<b>11</b>, 3-D LnGCOF) and {[Nd₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₁₀]­[Nd­(pza)­(pda)­(H₂O)]₂}­·12H₂O (<b>12</b>, 3-D LnGCOF) (Hpca = 2-picolinic acid, H₂pda = 2,6-pyridinedicarboxylic acid, Hpza = 2-pyrazinecarboxylic acid) were prepared by introducing the second auxiliary ligands into the organogermanate–lanthanide–oxide reaction system. The obtainment of these LnGs realized the utilization of the second auxiliary ligands inducing the assembly from 1-D LnGCOCs to 2-D LnGCOLs and 3-D LnGCOFs based on LnG cluster (LnGC) {Ln₈Ge₁₂E₁₂­(μ₃-O)₂₄­(H₂O)₁₆}­({Ln₈Ge₁₂}) units and Ln–organic complexes or organic ligand connectors. It should be noted that the well-organized structural constructions of <b>1</b>–<b>12</b> can be visualized as the gradual replacement of active water sites located at equatorial and polar positions on the hypothetical [Ln₈Ge₁₂­(μ₃-O)₂₄­E₁₂(H₂O)₁₈] LnGC core with oxygen or nitrogen atoms from organic ligands. The solid-state luminescent properties of <b>2</b>, <b>3</b>, <b>4</b>, <b>6</b>, and <b>8</b>–<b>12</b> have been investigated at room temperature

Additional file 2: of A practical community-based response strategy to interrupt Ebola transmission in sierra Leone, 2014–2015

Technical supplementary for practical community-based response strategy to interrupt Ebola transmission in Sierra Leone, 2014-2015. (DOC 721 kb

Additional file 1: of A practical community-based response strategy to interrupt Ebola transmission in sierra Leone, 2014–2015

Multilingual abstracts in the six official working languages of the United Nations. (PDF 299 kb