Lanthanide-Sensitized Upconversion Iridium Complex via Triplet Energy Transfer.

Cyclometalated iridium (Ir) complexes demonstrate impressive capabilities across a range of fields, including biology and photocatalysis, due to their tunable optical characteristics and structure flexibility. However, generating upconversion luminescence of Ir complexes under near-infrared light excitation is challenging. Herein, by employing lanthanide-doped upconversion nanoparticles (UCNPs) as the sensitizer, a new strategy is demonstrated to gain upconversion luminescence of Ir complexes via triplet energy transfer. This design relies on a rationally designed hybrid of core-shell structured NaYbF4:Tb@NaTbF4 UCNPs and new Ir phosphonate complexes, in which UCNPs can migrate upconverted energy to the surface of nanoparticles through Tb3+-mediated energy migration and then sensitize the upconversion luminescence of Ir complexes upon 980 nm excitation. Both experimental and theoretical investigations highlight the significance of triplet energy transfer from excited Tb3+ ions to the triplet state of Ir complexes in the sensitization of upconversion luminescence of Ir complexes. These findings may open exciting avenues for fabricating hybrid Ir materials with new functions and driving the development of UCNP-based nanomaterials.

Solvent modulation of the morphology of homochiral gadolinium coordination polymers and its impact on circularly polarized luminescence.

Studying the effect of morphology on the circularly polarized luminescence (CPL) of chiral molecular materials is important for the development of CPL-active materials for applications. Herein, we report that the morphology of Gd(NO3)3/R-,S-AnempH2 [AnempH2 = (1-anthrylethylamino)methylphosphonic acid] assemblies can be controlled by solvent modulation to form spiral bundles Gd(R-,S-AnempH)3·2H2O (R-,S-1), crystals Gd(R-,S-AnempH)3·2H2O (R-,S-2) and spindle-shaped particles Gd(R-,S-AnempH)3·3H2O·0.5DMF (R-,S-3) with similar chain structures. Interestingly, R-,S-1 are CPL active and show the highest value of dissymmetric factor among the three pairs of enantiomers (|glum| = 2.1 × 10-3), which is 2.8 times larger than that of R-,S-2, while R-,S-3 are CPL inactive with |glum| ≈ 0. This work provides a new route to control the morphology of chiral coordination polymers and improve their CPL performance.

Enhancing the Circularly Polarized Luminescence of Europium Coordination Polymers by Doping a Chromophore Ligand into Superhelices.

Lanthanide-based molecular materials showing efficient circularly polarized luminescence (CPL) activity with a high quantum yield are attractive due to their potential applications in data storage, optical sensors, and 3D displays. Herein we present an innovative method to achieve enhanced CPL activity and a high quantum yield by doping a chromophore ligand into a coordination polymer superhelix. A series of homochiral europium(III) phosphonates with a helical morphology were prepared with the molecular formula S-, R-[Eu(cyampH)3-3n(nempH)3n]·3H2O (S/R-Eu-n, n = 0-5%). The doping of chromophore ligand S- or R-nempH2 into superhelices of S/R-Eu-0% not only turned on the CPL activity with the dissymmetry factor |glum| on the order of 10-3 but also increased the quantum yield by about 14-fold. This work may shed light on the development of efficient CPL-active lanthanide-based coordination polymers for applications.

Macroscopic Helical Assembly of One-Dimensional Coordination Polymers: Helicity Inversion Triggered by Solvent Isomerism.

Assembling macroscopic helices with controllable chirality and understanding their formation mechanism are highly desirable but challenging tasks for artificial systems, especially coordination polymers. Here, we utilize solvents as an effective tool to induce the formation of macroscopic helices of chiral coordination polymers (CPs) and manipulate their helical sense. We chose the Ni/R-,S-BrpempH2 system with a one-dimensional tubular structure, where R-,S-BrpempH2 stands for R-,S-(1-(4-bromophenyl)ethylaminomethylphosphonic acid). The morphology of the self-assemblies can be controlled by varying the cosolvent in water, resulting in the formation of twisted ribbons of R-,S-Ni(Brpemp)(H2O)·H2O (R-,S-2T) in pure H2O; needle-like crystals of R-,S-Ni(Brpemp)(H2O)2·1/3CH3CN (R-,S-1C) in 20 vol % CH3CN/H2O; nanofibers of R-,S-Ni(Brpemp)(H2O)·H2O (R-,S-3F) in 20-40 vol % methanol/H2O or ethanol/H2O; and superhelices of R-,S-Ni(Brpemp)(H2O)·H2O (R-,S-4H or 5H) in 40 vol % propanol/H2O. Interestingly, the helicity of the superhelix can be controlled by using a propanol isomer in water. For the Ni/R-BrpempH2 system, a left-handed superhelix of R-4H(M) was obtained in 40 vol % NPA/H2O, while a right-handed superhelix of R-5H(P) was isolated in 40 vol % IPA/H2O. These results were rationalized by theoretical calculations. Adsorption studies revealed the chiral recognition behavior of these compounds. This work may contribute to the development of chiral CPs with a macroscopic helical morphology and interesting functionalities.

Macroscopic handedness inversion of terbium coordination polymers achieved by doping homochiral ligand analogues.

Inspired by natural biological systems, chiral or handedness inversion by altering external and internal conditions to influence intermolecular interactions is an attractive topic for regulating chiral self-assembled materials. For coordination polymers, the regulation of their helical handedness remains little reported compared to polymers and supramolecules. In this work, we choose the chiral ligands R-pempH2 (pempH2 = (1-phenylethylamino)methylphosphonic acid) and R-XpempH2 (X = F, Cl, Br) as the second ligand, which can introduce C-H⋯π and C-H⋯X interactions, doped into the reaction system of the Tb(R-cyampH)3·3H2O (cyampH2 = (1-cyclohexylethylamino)methylphosphonic acid) coordination polymer, which itself can form a right-handed superhelix by van der Waals forces, and a series of superhelices R-1H-x, R-2F-x, R-3Cl-x, and R-4Br-x with different doping ratios x were obtained, whose handedness is related to the second ligand and its doping ratio, indicating the decisive role of interchain interactions of different strengths in the helical handedness. This study could provide a new pathway for the design and self-assembly of chiral materials with controllable handedness and help the further understanding of the mechanism of self-assembly of coordination polymers forming macroscopic helical systems.

Layered lanthanide phosphonates Ln(2-qpH)(SO4)(H2O)2 (Ln = La, Ce, Pr, Nd, Sm): polymorphism and magnetic properties.

Polymorphic layered lanthanide coordination polymers provide opportunities to study the effect of intralayer and interlayer interactions on their magnetic dynamics. Herein we report a series of layered lanthanide phosphonates, namely, α-Ln(2-qpH)(SO4)(H2O)2 (Ln = Sm) (α-Ln), ß-Ln(2-qpH)(SO4)(H2O)2 (Ln = Pr, Nd, Sm) (ß-Ln) and γ-Ln(2-qpH)(SO4)(H2O)2 (Ln = La, Ce, Pr, Nd, Sm) (γ-Ln) (2-qpH2 = 2-quinolinephosphonic acid), which crystallize in monoclinic P21/c (α-Ln), triclinic P1̄ (ß-Ln) and orthorhombic Pbca (γ-Ln) space groups, respectively. The structural differences between the ß- and γ-phases lie not only in the intralayer but also in the interlayer. Within the layers, the Ln2O2 dimers are aligned parallel in the ß-phase, but are non-parallel in the γ-phase. In the interlayer, there are π-π interactions between the quinoline groups in the α- and ß-phases but not in the γ-phase. Magnetic studies reveal a field-induced slow relaxation of the magnetisation at low temperatures for compounds γ-Ce, ß-Nd, and γ-Nd, and the impact of polymorphism on the magnetic dynamics of Nd(III) compounds is discussed.

Octahedral lanthanide clusters containing a central PO43- anion: structural, luminescent, magnetic and relaxometric properties.

Lanthanide clusters with good stability and intriguing physical properties are attractive in many fields. By reacting 9-anthracenylphosphonic acid (AnPO3H2) and lanthanide nitrates under solvothermal conditions, we obtained a series of hexanuclear lanthanide phosphonate cages [H3O][Ln6(PO4)(AnPO3)8(DMF)6]·2DMF·H2O (Ln6, Ln = NdIII, EuIII, GdIII, DyIII, HoIII, ErIII, YbIII). Within the cluster, the six Ln atoms form an octahedron and its eight faces are covered by phosphonate groups. The in situ generated phosphate anion resides inside the cage and binds to the six Ln atoms via its four oxygen atoms. Photoluminescence studies show that Nd6, Er6 and Yb6 can emit near-infrared (NIR) luminescence due to the energy transfer from the anthracene ligand to the lanthanide ions. Magnetic studies reveal the magnetocaloric effect of Gd6 with an entropy change (-ΔSm) of 25.92 J kg-1 K-1 at 2.5 K and ΔH = 0-7 T. The possibility of using Gd6 as a contrast agent for magnetic resonance imaging was also explored with longitudinal (r1) and transverse (r2) relaxivities of 5.68 mM-1 s-1 per Gd and 158.11 mM-1 s-1 per Gd, respectively.

Co-infection of TYLCV and ToCV increases cathepsin B and promotes ToCV transmission by Bemisia tabaci MED.

Tomato disease is an important disease affecting agricultural production, and the combined infection of tomato chlorosis virus (ToCV) and tomato yellow leaf curl virus (TYLCV) has gradually expanded in recent years, but no effective control method has been developed to date. Both viruses are transmitted by Bemisia tabaci Mediteranean (MED). Previously, we found that after B. tabaci MED was fed on ToCV-and TYLCV-infected plants, the transmission efficiency of ToCV was significantly higher than that on plants infected only with ToCV. Therefore, we hypothesize that co-infection could enhance the transmission rates of the virus. In this study, transcriptome sequencing was performed to compare the changes of related transcription factors in B. tabaci MED co-infected with ToCV and TYLCV and infected only with ToCV. Hence, transmission experiments were carried out using B. tabaci MED to clarify the role of cathepsin in virus transmission. The gene expression level and enzyme activity of cathepsin B (Cath B) in B. tabaci MED co-infected with ToCV and TYLCV increased compared with those under ToCV infection alone. After the decrease in cathepsin activity in B. tabaci MED or cathepsin B was silenced, its ability to acquire and transmit ToCV was significantly reduced. We verified the hypothesis that the relative expression of cathepsin B was reduced, which helped reduce ToCV transmission by B. tabaci MED. Therefore, it was speculated that cathepsin has profound research significance in the control of B. tabaci MED and the spread of viral diseases.

Photo-responsive Single-Molecule Magnet Showing 0D to 1D Single-Crystal-to-Single-Crystal Structural Transition and Hysteresis Modulation.

Photo-responsive lanthanide-based single-molecule magnets (SMM) hold great promise for future switching and memory devices. Herein, we report a dysprosium phosphonate [DyIII (SCN)2 (NO3 )(depma)2 (4-hpy)2 ] (1Dy), which features a supramolecular framework containing layers of hydrogen-bonding network and pillars of π-π interacted anthracene units. The photocycloaddition reaction of anthracene pairs led to a rapid and reversible single-crystal-to-single-crystal (SC-SC) structural transition to form the 1D coordination polymer [DyIII (SCN)2 (NO3 )(depma2 )(4-hpy)2 ]n (2Dy), accompanied by photoswitchable SMM properties with the reduction of effective energy barrier by half and the narrowing of the butterfly-like hysteresis loop. The diluted sample showed a photo-induced switch of the blocking temperature (TB ) from 3.8 K for 1Dy@Y to 2.6 K for 2Dy@Y. This work may inspire the construction of lanthanide-based molecular materials with targeted photo-responsive magnetic properties.

Photo-controllable heterostructured crystals of metal-organic frameworks via reversible photocycloaddition.

Metal-organic framework (MOF)-based heterostructures are attractive because they can provide versatile platforms for various applications but are limited by complex liquid epitaxial growth methods. Here, we employ photolithography to fabricate and control MOF-based heterostructured crystals via [4 + 4] photocycloaddition. A layered dysprosium-dianthracene framework, [Dy(NO3)3(depma2)1.5]·(depma2)0.5 (2) [depma2 = pre-photodimerized 9-diethylphosphonomethylanthracene (depma)] underwent a single-crystal-to-single-crystal transition at 140 °C to form [Dy(NO3)3(depma)(depma2)]·(depma2)0.5 (3). The dissociated anthracene moieties are face-to-face π-π interacted allowing a reversible photocycloaddition between 2 and 3. This structural transformation causes a luminescence switch between blue and yellow-green and thus can be used to fabricate erasable 2 + 3 heterostructured crystals for rewritable photonic barcodes. The internal strain at the heterostructure interface leads to photobending and straightening of the crystal, a photomechanical response that is fast, reversible and durable, even operating at 140 °C, making it promising for photoactuation. This work may inspire the development of intelligent MOF-based heterostructures for photonic applications.

Gene Expression Network and Circ_0008012 Promote Progression in MLL/AF4 Positive Acute Lymphoblastic Leukemia.

BACKGROUND: Acute lymphoblastic leukemia with MLL/AF4 rearrangement remains a major hurdle to improving outcomes. Gene network and circRNAs have been found to participate in tumorigenesis, while their roles in leukemia still need to be explored. Recent patents have shown that circRNAs exhibit the markers for the children ALL, although the target and related mechanism remain to be elucidated. OBJECTIVE: This study aims to explore the possible targets and mechanisms of ALL with MLLAF4 rearrangement. METHODS: We first generated a gene network focusing on MLL-AF4 rearrangement. Cell viability was determined with Cell Counting Kit-8 assay. The cell apoptosis was tested by the Annexin V/PI assay. The RNA-protein complexes were analyzed by qRT-PCR, and the pathway proteins were analyzed by western blot. RESULTS: This gene network was associated with biological processes, such as nucleic acid metabolism and immunity, indicating its key role in inflammation. We found that circ_0008012 was upregulated in MLL/AF4 ALL cells and regulated cell proliferation and apoptosis. Further computed simulation and RIP showed that IKKß was the strongest protein in the NF-κB pathway binding with circ_0008012. As a result, possible regulation of circ_0008012 is suggested by binding IKKß in the IKKα:IKKß:IKKγ compound, which then phosphorylates IκB and activates NF- κB:p65:p300 compound in cell nucleus, thereby leading to leukemia. CONCLUSION: We identified a gene network for MLL/AF4 ALL. Moreover, circ_0008012 may be a therapeutic target for this subtype of ALL.

X-Ray Triggered Coordination-Bond Breakage in Dysprosium-Organic Framework and its Impact on Magnetic Properties.

Photosensitive lanthanide-based single-molecule magnets (Ln-SMM) are very attractive for their potential applications in information storage, switching, and sensors. However, the light-driven structural transformation in Ln-SMMs hardly changes the coordination number of the lanthanide ion. Herein, for the first time it is reported that X-ray (λ=0.71073 Å) irradiation can break the coordination bond of Dy-OH2 in the three-dimensional (3D) metal-organic framework Dy2 (amp2 H2 )3 (H2 O)6 ⋅ 4H2 O (MDAF-5), in which the {Dy2 (OPO)2 } dimers are cross-linked by dianthracene-phosphonate ligands. The structural transformation proceeds in a single-crystal-to-single-crystal (SC-SC) fashion, forming the new phase Dy2 (amp2 H2 )3 (H2 O)4 ⋅ 4H2 O (MDAF-5-X). The phase transition is accompanied by a significant change in magnetic properties due to the alteration in coordination geometry of the DyIII ion from a distorted pentagonal bipyramid in MDAF-5 to a distorted octahedron in MDAF-5-X.

Photocontrollable Magnetism and Photoluminescence in a Binuclear Dysprosium Anthracene Complex.

By incorporating photoreactive anthracene moieties into binuclear Dy2O2 motifs, we obtain two new compounds with the formulas [Dy2(SCN)4(L)2(dmpma)4] (1) and [Dy2(SCN)4(L)2(dmpma)2(CH3CN)2] (2), where HL is 4-methyl-2,6-dimethoxyphenol and dmpma is dimethylphosphonomethylanthracene. Compound 1 contains face-to-face π-π interacted anthracene groups that meet the Schmidt rule for a [4 + 4] photocycloaddition reaction, while stacking of the anthracene groups in compound 2 does not meet the Schmidt rule. Compound 1 undergoes a reversible single-crystal-to-single-crystal structural transformation upon UV-light irradiation and thermal annealing, forming a one-dimensional coordination polymer of [Dy2(SCN)4(L)2(dmpma)2(dmpma2)]n (1UV). The process is concomitant with changes in the magnetic dynamics and photoluminescent properties. The spin-reversal energy barrier is significantly increased from 1 (55.9 K) to 1UV (116 K), and the emission color is changed from bright yellow for 1 to weak blue for 1UV. This is the first binuclear lanthanide complex that exhibits synergistic photocontrollable magnetic dynamics and photoluminescence. Ab initio calculations are conducted to understand the magnetostructural relationships of compounds 1, 1UV, and 2.

Metagenomic analysis of the dynamical conversion of photosynthetic bacterial communities in different crop fields over different growth periods.

Photosynthetic bacteria are beneficial to plants, but knowledge of photosynthetic bacterial community dynamics in field crops during different growth stages is scarce. The factors controlling the changes in the photosynthetic bacterial community during plant growth require further investigation. In this study, 35 microbial community samples were collected from the seedling, flowering, and mature stages of tomato, cucumber, and soybean plants. 35 microbial community samples were assessed using Illumina sequencing of the photosynthetic reaction center subunit M (pufM) gene. The results revealed significant alpha diversity and community structure differences among the three crops at the different growth stages. Proteobacteria was the dominant bacterial phylum, and Methylobacterium, Roseateles, and Thiorhodococcus were the dominant genera at all growth stages. PCoA revealed clear differences in the structure of the microbial populations isolated from leaf samples collected from different crops at different growth stages. In addition, a dissimilarity test revealed significant differences in the photosynthetic bacterial community among crops and growth stages (P<0.05). The photosynthetic bacterial communities changed during crop growth. OTUs assigned to Methylobacterium were present in varying abundances among different sample types, which we speculated was related to the function of different Methylobacterium species in promoting plant growth development and enhancing plant photosynthetic efficiency. In conclusion, the dynamics observed in this study provide new research ideas for the detailed assessments of the relationship between photosynthetic bacteria and different growth stages of plants.

Photoresponsive proton conduction in Zr-based metal-organic frameworks using the photothermal effect.

A highly stable and porous MOF [Zr2(H4TPPP)(OH/F)2]·xH2O (1) containing a metal-free porphyrin-phosphonate ligand is reported. It shows high proton conductivity of 1.2 × 10-3 S·cm-1 at 25 °C and 95% RH, a photothermal effect over a wide spectral range from UV-vis to NIR, and photo-enhanced and switchable proton conductivity.

Polymorphism modulates photoluminescence and magnetic dynamics of mononuclear dysprosium-anthracene complexes.

Complexes α-Dy(depma)3Cl3 (α-DyCl), ß-Dy(depma)3Cl3 (ß-DyCl) and ß-Dy(depma)3Br3 (ß-DyBr) (depma = 9-diethylphosphono-methylanthracene) are reported. α-DyCl and ß-DyCl are polymorphs showing distinct magnetic dynamics with energy barriers of 32.3 K and 66.6 K. They also show distinct luminescence properties with emission peaks at 487 nm and 530 nm, respectively.

Layered Uranyl Phosphonates Encapsulating Co(II)/Mn(II)/Zn(II) Ions: Exfoliation into Nanosheets and Its Impact on Magnetic and Luminescent Properties.

Layered heterometallic 5f-3d uranyl phosphonates can exhibit unique luminescent and/or magnetic properties, but the fabrication and properties of their 2D counterparts have not been investigated. Herein we report three heterobimetallic uranyl phosphonates, namely, [(UO2 )3 M(2-pmbH)4 (H2 O)4 ] ⋅ 2H2 O [MU, M=Co(II), CoU; Mn(II), MnU; Zn(II), ZnU; 2-pmbH3 =2-(phosphonomethyl)benzoic acid]. They are isostructural and display two-dimensional layered structures where the M(II) centers are encapsulated inside the windows generated by the diamagnetic uranyl phosphonate layer. Each M(II) has an octahedral geometry filled with four water molecules in the equatorial positions and two phosphonate oxygen atoms in the axial positions. The uranium atoms adopt UO7 pentagonal bipyramidal and UO6 square bipyramidal geometries. The lattice and coordination water molecules can be released by thermal treatment and reabsorbed in a reversible manner, accompanied with changes of magnetic dynamics. Interestingly, the bulk samples of MU can be exfoliated in acetone via freezing and thawing processes forming nanosheets with single-layer or two-layer thickness (MU-ns). Magnetic studies revealed that the CoU and MnU systems exhibited field-induced slow magnetization relaxation at low temperature. Compared with crystalline CoU, the magnetic relaxation of the CoU-ns aggregates is significantly accelerated. Moreover, photoluminescence measured at 77 K showed slight red-shift of the five characteristic uranyl emission bands for ZnU-ns in comparison with those of the crystalline ZnU. This work gives the first examples of 2D materials based on 5f-3d heterometallic uranyl phosphonates and illustrates the impact of dimension reduction on their magnetic/optical properties.

pH and Salt-Assisted Macroscopic Chirality Inversion of Gadolinium Coordination Polymer.

The precise adjustment of handedness of helical architectures is important to regulate their functions. Macroscopic chirality inversion has been achieved in organic supramolecular systems by pH, metal ions, solvents, chiral and non-chiral additives, temperature, and light, but rarely in coordination polymers (CPs). In particular, salt-assisted macroscopic chirality inversion has not been reported. In this work, we carried out a systematic investigation on the role of pH and salt in regulating the morphology of CPs based on Gd(NO3)3 and R-(1-phenylethylamino)methylphosphonic acid (R-pempH2). Without extra NO3-, the chirality inversion from the left-handed superhelix R-M to the right-handed superhelix R-P can be achieved by pH modulation from 3.2 to 3.8. The addition of NaNO3 (2.0 eq) at pH 3.8 results in an inversion of chiral sense from R-P to R-M as a pure phase. To our knowledge, this is the first example of salt-assisted macroscopic helical inversion in artificial systems.

Uranyl phosphonates: crystalline materials and nanosheets for temperature sensing.

Ultrathin nanosheets of luminescent metal-organic frameworks or coordination polymers have been widely used for sensing ions, solvents and biomolecules but, as far as we are aware, not yet used for temperature sensing. Herein we report two luminescent uranyl phosphonates based on 2-(phosphonomethyl)benzoic acid (2-pmbH3), namely (UO2)(2-pmbH2)2 (1) and (H3O)[(UO2)2(2-pmb)(2-pmbH)] (2). The former has a supramolecular layer structure, composed of chains of corner-sharing {UO6} octahedra and {PO3C} tetrahedra which are connected by hydrogen bonds between phosphonate and carboxylic groups. Compound 2 possesses a unique 2D anionic framework structure, where the inorganic uranyl phosphonate chains made up of {UO7} and {PO3C} polyhedra are cross-linked by 2-pmb3- ligands. The carboxylic groups of 2-pmbH2- ligands are pendant on the two sides of the layers and form hydrogen bonds between the layers. Both compounds can be exfoliated in acetone via a top-down freeze-thaw method, resulting in nanosheets of two-layer thickness. Interestingly, the photoluminescence (PL) of 1 and 2 is highly temperature sensitive. Variable temperature PL studies revealed that compounds 1 and 2 can be used as thermometers in the temperature ranges 120-300 K and 100-280 K, respectively. By doping the nanosheets into polymer matrix, 1-ns@PMMA and 2-ns@PMMA were prepared. The PL intensity of 1-ns@PMMA is insensitive to temperature, unlike that of the bulk sample. While 2-ns@PMMA exhibits similar temperature-dependent luminescence behaviour to its bulk counterpart, thereby enabling its potential application as a thermometer in the temperature range 100-280 K.