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A multi-responsive Co-CP demonstrates turn-on ratiometric/turn-off fluorescence sensing activities.

A cutting [Na5Dy6] phosphonate cluster and a recombinant [Na4Dy8]∞ phosphonate layer are isolated using the pyrazinyl hydrazone ligand. The latter presents the first heterometal phosphonate exhibiting triple N-bridges of pyrazinyl groups.

Lanthanide-iron clusters usually display interesting structures and outstanding magnetic properties. However, due to the high reactivity (acidity) of the Fe

The reactions of (E)-quinoline-2-carbaldehyde oxime (Hqcah) with Ni(ClO4)2·6H2O and NH4SCN and with Ni(CF3SO3)2 and NaN3 led to two solitary metallacrowns (MCs) ([Ni5(qcah)7(Hqcah)(CH3OH)(SCN)(OH)]·ClO4 (1) and [Ni4(qcah)4(N3)4(Py)4] (2), respectively. Complex 1 is a pentanuclear nickel cluster that exhibits two "fused" 9-MC-3 structural units with both rings possessing Ni2–N–O–Ni1–N–O–Ni5–O–N and Ni3–N–O–Ni4–O–Ni5–O–N connectivities. Complex 2 consists of four [Ni(qcah)(N3)(Py)] units with adjacent nickel atoms linked together through N–O groups to construct a tetranuclear 12-MC-4 metallacrown. The ligands exhibit μ3:η2:η1:η1, μ2:η2:η1 and μ1:η2 coordination modes in 1 and μ2:η2:η1 coordination mode in 2. Magnetic property measurements and the fitting of various temperature magnetic susceptibilities revealed antiferromagnetic coupling between metal centers with the negative coupling parameters in both 1 and 2.

Five new mononuclear lanthanide complexes, [LnL

This paper reports two closely related heteropentanuclear manganese complexes, namely, {Na2Mn3(opch)3(μ4-O)(μ2-N3) (μ2-AcO)(μ2-MeO)}·6CH3OH·0.5H2O (1) and {Na2Mn3(opch)3(μ4-O)(μ2-N3)2(μ2-AcO)}·2.5CH3OH·2H2O (2), where H2opch is (E)-N′-(2-hydroxy-3-methoxybenzylidene)pyrazine-2-carbohydrazide. Single-crystal X-ray diffraction analysis reveals that the trigonal bipyramidal skeletons in both complexes are comparable, where a perfect triangular Mn3 motif occupies the equatorial plane. Magnetic investigations suggest that overall antiferromagnetic coupling is present within the triangles of 1 and 2. However, their dynamic magnetic properties are drastically distinct. Indeed, complexes 1 and 2 show two kinds of dual slow magnetic relaxation processes that correspond to anisotropy barriers (Δ) of 9.2 cm−1 (11.4 cm−1 for 2) and 12.8 cm−1 (30.0 cm−1 for 2) for the low- and high-frequency domains, respectively. More importantly, a further comparative study of the structure and magnetism indicates that the coordination sphere of these two model complexes with the homologous hydrazone-based coordination sites undergoes an alteration from methoxide-O to azide-N upon a subtle change of the auxiliary anion accompanied by modulating octahedron geometries, leading to a further influence on different relaxation dynamics.

{Dy16(μ6-C10H7PO3)2(μ5-C10H7PO3)8(spch)8(μ3-OH)2(μ2-OH)2(μ2-AcO)6(μ3-COO)2(DMF)2(H2O)6}·0.5CH3OH·4.5H2O (1) and {Dy16(μ5-C10H7PO3)4(μ3-C10H7PO3)12(μ2-C10H7PO3H)8(opch)4(DMF)8(MeOH)4}·2.5CH3OH·3H2O (2), where H2spch is ((E)-N'-(2-hydroxybenzylidene)pyrazine-2-carbohydrazide, C10H7PO3H2 is 1-naphthylphosphonic acid and H2opch is (E)-N'-(2-hydroxy-3-methoxybenzylidene)pyrazine-2-carbohydrazide, were successfully synthesized by varying the hydrazone ligands in the Dy-phosphonate system. It is important that the ellipsoidal core experiences a ring forming structural transformation to the supramolecular square motif upon the incorporation of an ortho-methoxy substituent into the hydrazone. Alternating-current (ac) magnetic susceptibility studies of 1 and 2 suggest that similar single molecule magnet behaviors occur for these two complexes. The result represents an effective molecular assembly tactic to develop highly complicated lanthanide coordination clusters through the multicomponent self-assembly of the coalescence of phosphonate- and hydrazone-based ligands and metal salts.

This paper reports a quasilinear hydrazone-based mononuclear dysprosium(III) compound, namely, {Dy(Hppyh)2(SCN)3}·2MeOH (I), where Hppyh is pyrazine-2-carboxylic acid pyridin-2-ylmethylene-hydrazide. Compound I behaves as a single-ion magnet (SIM) based on the optimal dc field application of 0.7 kOe, showing a complex magnetic relaxation phenomenon with a tunneling relaxation time of 6.1 ± 0.3 × 10−3 s and an effective spin reversal barrier of 22.6 ± 1.1 K for the low- and high-frequency regions, respectively. More importantly, detailed comparative experimental and theoretical investigations reveal that the complex magnetic relaxation was most likely associated with the single DyIII ion behavior as well as the short-range intermolecular magnetic dipolar interactions.

Two heterometallic metallacrown complexes, [Er{Cu4(butyrat)4}2]·Cl3·MeOH·26H2O (1) and [Yb{Cu4(butyrat)4}2]·Cl3·MeOH·26H2O (2) (H2butyrat = 3-aminobutyric hydroxamic acid), have been reported. X-ray crystallographic analysis reveals that the two complexes displayed nested-sandwich configurations with two 12-MC-4 metallacrown units capping LnIII in the centre. Magnetic studies revealed that 1–2 undergo antiferromagnetic coupling interaction. Magnetic measurements show that complex 2 displays frequency-dependent signals at a dc field of 1000 Oe, indicating field-induced single-molecule magnet behavior.

Four coordination compounds {[Cd(L)1/2(H2O)2]·2H2O}n (1), {[Ni2(L)(bpyBr)2(H2O)2]·H2O}n (2), {[Ni(H2L)(bipy)(H2O)]·H2O}n (3), and [Co(H2L)(bipy)(H2O)2]n (4) (H4L = 5,5′-(pentane-1,4-diylbis(oxy))diisophthalic acid, bpyBr = 4,4′-dibromo-2,2′-bipyridyl, bipy = 4,4′-bipyridine) were synthesized and characterized. These four compounds exhibit a 3D open framework with channels, a 2D layer, a 3D supramolecular network constructed from coordination layers and a 3D supramolecular network constructed from coordination chains, respectively. The reaction temperature can influence the coordination modes of the organic multi-carboxylate ligands and the acidity of the compounds. AC impedance spectral studies suggest that the order of proton conductivity of compounds 1–4 is 3 > 4 > 1 > 2. The result reveals that the proton conductivities of low dimensional nonporous CPs 3 and 4 are higher than that of high dimensional porous CP 1. The structure–property studies reveal that the highest proton conductivity of 3 may be explained by its acidic hydrophilic groups and highest water uptake. The dimensionality and channels of the CPs can't influence proton conductivity directly. Meanwhile the amount and orientation of hydrophilic groups can decide the water absorption ability of the CPs, which is an important factor on proton conductivity. The protonation degree of hydrophilic groups, i.e. the acidity of the CPs is the first influencing factor. So, large amounts of hydrophilic groups with high protonation degrees should be considered firstly in the design and synthesis of CPs with good proton conducting performance.

We have prepared three 3d–4f heterometallic complexes, namely[Ln3Zn3(Hvanox)3(vanox)3(NO3)6(H2O)5]·nEtOH (LnIII = Dy, n = 3 (1), LnIII = Tb, n = 5 (2), LnIII = Er, n = 5 (3)), by the reaction of o-vanillin oxime (H2L) with Zn(NO3)2·6H2O and Ln(NO3)2·6H2O salts in the presence of triethylamine. Single Crystal X-ray diffraction shows Zn ions and Ln ions are linked together to display a windmill-like framework with the dinuclear LnZn(HL)(L) as flabellum. Magnetic measurements reveal that complexes 1 and 2 exhibit field-induced frequency-dependence signals, indicating single-molecule magnetism (SMM) behaviors, while complex 3 exhibits slow magnetic relaxation.

This paper reports two closely related heteropentanuclear manganese complexes, namely, {Na

There are few studies on the genetic changes of meniscus degeneration. We used anterior cruciate ligament resection of Wuzhishan pig to prepare a meniscus degeneration model, and applied gene chip technology to detect differentially expressed genes in degenerative meniscus tissue. Then we applied GO analysis, Pathway analysis, Core gene network analysis and Relevant miRNAs analysis to discover relevant regulatory networks of meniscus degeneration. As a result, we detected 893 differentially expressed genes, mainly involving hormone, apoptosis, inflammation and other mechanisms, and obtained MUC13, Inflammatory mediator regulation of TRP channels, MDFI, mir-335-5p and so on that may play a key role. In summary, we have established a reliable animal model of meniscus degeneration and found that meniscus degeneration involves several possible molecular mechanisms, which will provide molecular targets for further research of the disease in the future.

By changing the stoichiometric ratios, the one-pot reaction of the glycinehydroxamic acid (H2glyha) ligand with copper(II) and lanthanide(III) salts in the presence of diamagnetic [Na2{Fe(CN)5(NO)}] led to two series of isostructural complexes, which can be designated as heterotrimetallic dimeric clusters [{LnCu5(glyha)5}{Fe(CN)5(NO)}(H2O)4]2·xNO3·yH2O (x = 2, y = 11 for La (1), x = 2, y = 11 for Pr (2), and x = 2, y = 11 for Nd (3)) and heterotetrametallic coordination polymers [Na{LnCu5(glyha)5}{Fe(CN)5(NO)}2(H2O)x·yH2O]n (x = 6, y = 4 for Sm (4), x = 6, y = 0 for Gd (5), x = 6, y = 4 for Tb (6), x = 5, y = 5 Dy (7), and x = 6, y = 4 for Ho (8)). Each molecular structure contains LnIII[15-metallacrown-5] nodes and diamagnetic [Fe(CN)5(NO)]2− linkers. The resulting products demonstrate diversified structural frameworks due to the radius effect of LnIII ions and different bridging fashions of diamagnetic [Fe(CN)5(NO)]2− linkers. An analysis of magnetic susceptibilities reveals that 7 exhibits ferromagnetic coupling between CuII and DyIII ions and field-induced SMM behavior.

A system of CO32–-bridged polynuclear dysprosium complexes has been complemented with the emergence of a key component, namely, [Dy6(μ4-CO3)3(μ3-OH2)(spch)6(MeOH)6(H2O)3]·4MeOH·3H2O (3), and thus four dysprosium(III) clusters (1–4) spontaneously fixing one, two, three, and four atmospheric CO2 molecules, respectively, have been successfully assembled. Compound 1 is a Dy6 single-molecular magnet (SMM) (1) based on Dy3 triangles, with one CO32– group being derived from atmospheric CO2. The incorporation of an ortho-methoxy substituent into the ligand enables access to a double-CO32– bridged Dy6 SMM (2), where two CO32– groups occupy the two bases of the triangular prism. The trapping of three CO2 molecules of the atmosphere results in the formation of compound 3, where the three CO32– groups reside on the lateral faces of a triangular prismoid. Finally, a Dy8 SMM (4) with four CO32– bridges on the four lateral faces of the square prismoid can be isolated by converting four CO2 molecules. The magnetic invest...

A decanuclear dysprosium phosphonate (I) undergoes two consecutive SC–SC transformations, associated with OFF–ON–OFF switching of its single-molecule-magnetism., {Dy5(EDDC)2(μ3-AcO)2(μ5-C15H11PO3)(μ4-C15H11PO3)(μ2-AcO)2(AcO)2(H2O)(CH3OH)2}2(μ4-C2O4)·xH2O (I), where H2EDDC is N′,N′′,E,N′,N′′,E-N′,N′′-(ethane-1,2-diylidene)dipyrazine-2-carbohydrazide and C15H11PO3H2 is 9-anthrylmethylphosphonic acid, is found to undergo two consecutive single-crystal-to-single-crystal transformations. The first is under UV irradiation (λ = 365 nm for 3 d in air) to {Dy5(EDDC)2(μ3-AcO)2(μ5-C15H11PO3)2(μ2-AcO)2(AcO)2(H2O)3}2(μ4-C2O4)·xH2O (I-UV) where the two CH3OH are replaced by two H2O and the second by annealing under N2 at 100 °C on a diffractometer or under Ar in a glovebox to {Dy5(EDDC)2(μ3-AcO)2(μ5-C15H11PO3)2(μ2-AcO)4(H2O)}2(μ4-C2O4) (I-A-N2 or I-A-Ar) where it has lost two H2O molecules. The second transformation is reversible by exposure to air at room temperature (I-A-N2-cool). While the overall structures are the same (retaining the space group P21/c), there is a considerable expansion of the unit cell from I (8171 Å3) to I-UV (8609 Å3) and I-A-N2 (8610 Å3) and the coordinations of the Dy atoms undergo major reconstructions. This is associated with switching the single-molecule-magnetism (SMM) from OFF for I to ON for I-UV and to OFF again for I-A-Ar in air. Such a switching mechanism associated with the retention of crystallinity is unique in the chemistry of dysprosium. The structure of the molecule is formed from two symmetry related pentamers joined by an oxalate. A related compound containing two isolated neutral pentamers {Dy5(EDDC)2(μ3-AcO)2(μ5-C15H11PO3)2(μ2-AcO)3(AcO)2(H2O)2}{Dy5(EDDC)2(μ3-AcO)2(μ5-C15H11PO3)(μ4-C15H11PO3)(μ2-AcO)3(AcO)2(CH3OH)2}·2CHCl3 (II) has also been isolated with closely related Dy coordination and it exhibits similar SMM behaviour in zero field.

Ultrathin cation-exchanged layered metal oxides are promising for many applications, while such substances are barely successfully synthesized to show several atomic layer thickness, owing to the strong electrostatic force between the adjacent layers. Herein, we took LiCoO2, a prototype cation-exchanged layered metal oxide, as an example to study. By developing a simple synthetic route, we synthesized LiCoO2 nanosheets with 5–6 cobalt oxide layers, which are the thinnest ever reported. Ultrathin nanosheets thus prepared showed a surprising coexistence of increased oxidation state of cobalt ions and oxygen vacancy, as demonstrated by magnetic susceptibility, X-ray photoelectron, electron paramagnetic resonance, and X-ray absorption fine spectra. This unique feature enables a higher electronic conduction and electrophilicity to the adsorbed oxygen than the bulk. Consequently ultrathin LiCoO2 nanosheets provided a current density of 10 mA cm–2 at a small overpotential of a mere 0.41 V and a small Tafel slope...

An ingenious self-assembly method has been employed to achieve noncentered cyclic metal cages by integrating single and double pyrazinyl hydrazone ligands in the presence of an organo phosphonic acid. An even-numbered hexanuclear and an odd-numbered heptanuclear dysprosium(III) cluster, namely [Dy6(spch)6(O3PC10H7)2(pyra)2(MeOH)(H2O)]·8.5H2O [1, H2spch = (E)-N′-(2-hydroxybenzylidene)pyrazine-2-carbohydrazide, pyra = pyrazine-2-carboxylate] and [Dy7(eddc)2(spch)2(O3PC10H7)4(OAc)5(MeOH)4]·4MeOH [2, H2eddc = (E,E)-N′,N′′-(ethane-1,2-diylidene)bis(pyrazine-2-carbohydrazide)] have been synthesized successfully. Single-crystal X-ray diffraction analysis revealed that compound 1 is composed of six identical [Dy2(spch)]4+ building blocks containing a single pyrazinyl hydrazone ligand of spch2– welded to each other to form a hexanuclear ring, whereas compound 2 possesses an enlarged skeleton with a heptanuclear ring made up of two [Dy3(eddc)]7+ and two [Dy2(spch)]4+ building blocks by virtue of the inclusion in the synthesis of double pyrazinyl hydrazone ligand eddc2–. Compounds 1 and 2 exhibit drastically distinct dynamic magnetic properties. Compound 1 shows a complex slow relaxation of the magnetization with two types of temperature dependence with energy barriers (Ueff) of 4.7 and 20.3 K and pre-exponential factors (τ0) of 9.1 × 10–5 and 2.6 × 10–6 s for the low- and high-temperature regimes, respectively, whereas compound 2 exhibits a two-step relaxation process (Ueff(1): 45.1 K, τ0(1): 4.4 × 10–7 s; Ueff(2): 48.7, τ0(2): 2.7 × 10–8 s) in the out-of-phase alternating current signals.

A heptanuclear and a dimer of heptanuclear dysprosium clusters (Dy7 and Dy14) have been successfully synthesized by ingenious coalescence of the single and double pyrazinyl hydrazone as well as phosphonate ligands. The complexes feature the largest odd-numbered cyclic lanthanide clusters reported thus far. Both exhibit single molecule magnet behaviors at low temperature.

A microporous Tm-MOF {[Tm2L2(ox)(H2O)2]·4H2O}n (Tm-MOF, L ​= ​2-(pyridin-4-yl)-2H-imidazole-4, 5-dicarboxylate dianion; ox ​= ​oxalate dianion) with hydrogen bonds between the guest water molecules and host framework has been obtained. The CV and AC impendence studies suggested there was remarkable proton conducting behavior within Tm-MOF crystals, which was influenced by external voltage. The proton conducting mechanism was explored through dynamic simulation calculation. It was suggested that proton transferred between L ligand and water molecules through hydrogen bonds. And L ligand can isomerize to excited state stimulated by external voltage, which was essential and ensured the continuity of proton transfer. This simulated proton conduction process was verified by the fact that the low proton conductivity at 0 ​V vs. Ag-AgCl increased dramatically while open-circuit voltage increased to 1.6 ​V vs. Ag-AgCl. The UV absorption peak red shifting under higher voltage and the Ea value of 0.22eV lower than 0.4eV also confirmed the result of dynamic simulation.

The double chloride-bridged dimer of a dinuclear dysprosium(III) single-molecule magnet (SMM) was successfully isolated by assembling centrosymmetric dinuclear Dy2 SMMs. Such structural transformation involves the generation and cleavage of chloride bridges and leads to consecutive transformations of one- and two-step slow relaxation of magnetization.

The magnetic relaxation and magnetization blocking barriers of tailor-made homo- and heterodinuclear compounds [Dy2 (opch)2 (OAc)2 (H2 O)2 ]⋅MeOH (1) and [DyMn(opch)2 (OAc)(MeOH)(H2 O)2 ] (2), where H2 opch is (E)-N'-(2-hydroxy-3-methoxybenzylidene)pyrazine-2-carbohydrazide, were systematically investigated and the change in single-molecule magnet behavior originating from targeted replacement of one dysprosium site in the Dy2 compound with manganese was elucidated through a combination of experimental and theoretical studies. A detailed comparative study on these closely related model compounds revealed remarkable changes of the crystal-field splitting and anisotropy of the Dy site and the total exchange spectrum due to the replacement of Dy by Mn. The blocking barriers of these two compounds, which explain their different relaxation behaviors, were analyzed. The two Ising doublets arising from the magnetic interaction in the case of 1 are strongly uniaxial, with tunneling splittings smaller than 10-6 cm-1 , and this leads to magnetic relaxation at temperatures exceeding the exchange energy (2.14 cm-1 ), which involves transition via the excited states corresponding to local transitions on the excited doublet at the Dy site. The third and fourth exchange doublets in 2 (located at 2.16 and 3.25 cm-1 , respectively) show much larger tunneling splittings (of 10-4 and 10-3 cm-1 , respectively), and thus open an important path for magnetic relaxation.

Ultrathin cation-exchanged layered metal oxides are promising for many applications, while such substances are barely successfully synthesized to show several atomic layer thickness, owing to the strong electrostatic force between the adjacent layers. Herein, we took LiCoO

Two cyclic lanthanide clusters based on a rationally designed double pyrazinyl hydrazone ligand EDDC2−, namely, [Dy6(EDDC)2(OAc)14(H2O)2]·MeOH·2H2O (1) and [Dy8(EDDC)4(O3PC10H7)4(OAc)8(H2O)4]·12H2O (2) are reported. The latter shows slow magnetization relaxation below 12 K.

Injectable three-dimensional (3D) scaffolds have the advantages of fluidity and moldability to fill irregular-shaped defects, simple incorporation of bioactive factors, and limited surgical invasiveness. Adipose-derived stem cells (ADSCs) are multipotent and can be differentiated toward nucleus pulposus (NP)-like cells. A hypoxic environment may be important for differentiation to NP-like cells because the intervertebral disc is an avascular tissue. Hence, we investigated the induction effects of hypoxia and an injectable 3D chitosan-alginate (C/A) gel scaffold on ADSCs.The C/A gel scaffold consisted of medical-grade chitosan and alginate. Gel porosity was calculated by liquid displacement method. Pore microstructure was analyzed by light and scanning electron microscopy. ADSCs were isolated and cultured by conventional methods. Passage 2 BrdU-labeled ADSCs were co-cultured with the C/A gel. ADSCs were divided into three groups (control, normoxia-induced, and hypoxia-induced groups). In the control group, cells were cultured in 10% FBS/DMEM. Hypoxia-induced and normoxia-induced groups were induced by adding transforming growth factor-β1, dexamethasone, vitamin C, sodium pyruvate, proline, bone morphogenetic protein-7, and 1% ITS-plus to the culture medium and maintaining in 2% and 20% O2, respectively. Histological and morphological changes were observed by light and electron microscopy. ADSCs were characterized by flow cytometry. Cell viability was investigated by BrdU incorporation. Proteoglycan and type II collagen were measured by safranin O staining and the Sircol method, respectively. mRNA expression of hypoxia-inducing factor-1α (HIF-1α), aggrecan, and Type II collagen was determined by reverse transcription-polymerase chain reaction.C/A gels had porous exterior surfaces with 80.57% porosity and 50-200 üm pore size. Flow cytometric analysis of passage 2 rabbit ADSCs showed high CD90 expression, while CD45 expression was very low. The morphology of induced ADSCs resembled that of NP cells. BrdU immunofluorescence showed that most ADSCs survived and proliferated in the C/A gel scaffold. Scanning electron microscopy showed that ADSCs grew well in the C/A gel scaffold. ADSCs in the C/A gel scaffold were positive for safranin O staining. Hypoxia-induced and normoxia-induced groups produced more proteoglycan and Type II collagen than the control group (P0.05). Proteoglycan and Type II collagen levels in the hypoxia-induced group were higher than those in the normoxia-induced group (P0.05). Compared with the control group, higher mRNA expression of HIF-1α, aggrecan, and Type II collagen was detected in hypoxia-induced and normoxiainduced groups (P0.05). Expression of these genes in the hypoxia-induced group was significantly higher than that in the normoxia-induced group (P0.05).ADSCs grow well in C/A gel scaffolds and differentiate toward NP-like cells that produce the same extracellular matrix as that of NP cells under certain induction conditions, which is promoted in a hypoxic state.

Two new butterfly-shaped pentanuclear dysprosium(III) clusters, [Dy-5((3)-OH)(3)(opch)(6)(H2O)(3)]3MeOH 9H(2)O (1) and [Dy-5((3)-OH)(3)(Hopch)(2)(opch)(4)(MeOH)(H2O)(2)](ClO4)(2) 6MeOH4H(2)O (2), which were based on the heterodonor-chelating ligand o-vanillin pyrazine acylhydrazone (H(2)opch), have been successfully synthesized by applying different reaction conditions. Single-crystal X-ray diffraction analysis revealed that the butterfly-shaped cores in both compounds were comparable. However, their magnetic properties were drastically different. Indeed, compound 1 showed dual slow-relaxation processes with a transition between them that corresponded to energy gaps () of 8.1 and 37.9K and pre-exponential factors ((0)) of 1.7x10(-5) and 9.7x10(-8)s for the low- and high-temperature domains, respectively, whilst only a single relaxation process was noted for compound 2 (=197K, (0)=3.2x10(-9)s). These significant disparities are most likely due to the versatile coordination of the H(2)opch ligands with particular keto-enol tautomerism, which alters the strength of the local crystal field and, hence, the nature or direction of the easy axes of anisotropic dysprosium ions.

A novel octanuclear dysprosium(III) compound, templated by quadruple μ(4)-CO(3)(2-) introduced via spontaneous fixation of atmospheric carbon dioxide, shows single-molecule-magnet behaviour with an obvious hysteresis loop detected by a traditional SQUID magnetometer.

A unique hexanuclear dysprosium(III) compound with a new polydentate Schiff-base ligand shows complex slow relaxation of the magnetization most likely associated with the single-ion behavior of individual Dy(III) ions as well as the possible weak coupling between them.