Cationic Europium-Organic Framework for Chromatographic Column Separation of Ionic Dyes and Stimuli-Responsive Chromic Properties.

A novel 3D europium-based cationic framework (Eu-CMOF) has been constructed solvothermally by employing a viologen derivative as an organic functional building unit. Notably, Eu-CMOF demonstrates its capability as a proficient aqueous-phase ion-exchange host, facilitating the remarkable rapid chromatographic column separation of new coccine and malachite green (NC3-/MG+), as well as new coccine and methylene blue (NC3-/MLB+), in mere 2 to 4 min. Adsorption thermodynamics and kinetics of anionic dyes demonstrate that Eu-CMOF exhibits a higher adsorption capacity for NC3-, as evaluated by the Langmuir model, reaching a value of 173 mg·g-1. The pseudo-second-order rate constant is determined to be 3.84 × 10-3 mg-1·g·min-1. Additionally, Eu-CMOF displays reversible photochromic and amine- and ammonia-induced vapochromic behaviors. Further mechanistic studies reveal that these chromic behaviors are primarily attributed to the generation of free viologen radical stimulated by Xe-light or electron-rich amine/ammonia. This research contributes to the development of advanced materials with applications in rapid chromatographic separation and stimuli-responsive chromic properties, showcasing the potential of Eu-CMOF as a versatile platform for practical applications.

A Multifunctional Coordination Polymer Constructed by Viologen Derivatives: Photochromism, Chemochromism, and MnO4- Sensing.

A multifunctional Cd-based coordination polymer based on a viologen derivative and a secondary carboxylic ligand, namely, {[Cd2(bcbp)(pta)2 (H2O)]·2H2O}n (1, H2bcbpCl2 = 1,1'-bis(4-carboxyphenyl)-(4,4'-bipyridinium) dichloride, H2pta = p-phthalic acid), has been solvothermally synthesized and structurally characterized. Compound 1 is a 3D framework built on {Cd2(pta)2 (H2O)}n net with square channels which intalls bcbp ligands at the diagonal position of the two adjacent square channels. Notably, compound 1 exhibits a reversible photochromic transformation between yellowish gray and dark green under xenon light irradiation, which should be attributed to the formation of free viologen radicals. Furthermore, compound 1 also displays a chemochromic phenomenon from yellowish gray to dark green after exposure to ammonia and hydrazine, which could be ascribed to the generation of viologen radicals and charge-transfer complexes triggered by nucleophilic attack of electron-rich ammonia and hydrazine molecules to the electron-deficient viologen moiety in the bcbp ligand. Moreover, compound 1 is capable of quickly and selectively detecting MnO4- with a high quenching coefficient and a low limit of detection via a luminescent quenching process caused by the competitive absorption of excitation energy.

Sodalite Cd66-Cage-Based Metal-Organic Framework Constructed by Cd9 and Cd5 Metal-Organic Clusters.

A sodalite Cd66-cage-based metal-organic framework (MOF), namely, CPM-9S, has been constructed based on Cd9 and Cd5 metal-organic clusters (MOCs), which, to the best our knowledge, represents the first Cd-cage-based MOF that contains the highest-nuclear Cd-based MOC and the largest number of Cd2+ ions in a cage. The iodine adsorption performances in terms of the iodine adsorption capacity, adsorption isotherm, and adsorption kinetics, as well as the adsorption mechanism, have been further studied.

Viologen-Based Cationic Metal-Organic Framework for Efficient Cr2O72- Adsorption and Dye Separation.

A novel cationic metal-organic framework composed of {Cu2(COO)4} paddle-wheel units and a tetracarboxylic viologen derivative, namely, {[Cu2(bdcbp)(H2O)2]·2NO3·2H2O}n (Cu-CMOF, H4bdcbpCl2 = 1,1'-bis(3,5-dicarboxyphenyl)-4,4'-bipyridinium dichloride), has been successfully synthesized and structurally characterized. In Cu-CMOF, the {Cu2(COO)4} unit and viologen derivative both act as four-connected nodes forming an ssb-type cationic network with 42.84 topology, in which the positive charges are distributed on the organic viologen moieties. Deeper insight of the structure indicates that the 3D architecture of Cu-CMOF can be seen as packing of a 26-faceted polyhedral cage and two cuboid cages. Notably, Cu-CMOF displays a highly efficient anion exchange ability for capture and removal of anionic pollutants. UV-vis absorption spectra and digital images demonstrate that Cu-CMOF is capable of adsorbing the dichromate anion and anionic dyes effectively, such as methyl orange (MO-), Congo red (CR2-), and New Coccine (NC3-). Meaningfully, anionic dyes (MO-, CR2-, and NC3-) can be efficiently and selectively removed by Cu-CMOF in the presence of cationic dye methylene blue (MLB+). Such behaviors of anionic pollutant adsorption and dye separation are mainly caused by an ion-exchange process facilitated by the large cavity and decentralized distribution of positive charge in Cu-CMOF.

A Family of Highly Efficient CuI-Based Lighting Phosphors Prepared by a Systematic, Bottom-up Synthetic Approach.

Copper(I) iodide (CuI)-based inorganic-organic hybrid materials in the general chemical formula of CuI(L) are well-known for their structural diversity and strong photoluminescence and are therefore considered promising candidates for a number of optical applications. In this work, we demonstrate a systematic, bottom-up precursor approach to developing a series of CuI(L) network structures built on CuI rhomboid dimers. These compounds combine strong luminescence due to the CuI inorganic modules and significantly enhanced thermal stability as a result of connecting individual building units into robust, extended networks. Examination of their optical properties reveals that these materials not only exhibit exceptionally high photoluminescence performance (with internal quantum yield up to 95%) but also that their emission energy and color are systematically tunable through modification of the organic component. Results from density functional theory calculations provide convincing correlations between these materials' crystal structures and chemical compositions and their optophysical properties. The advantages of cost-effective, solution-processable, easily scalable and fully controllable synthesis as well as high quantum efficiency with improved thermal stability, make this phosphor family a promising candidate for alternative, RE-free phosphors in general lighting and illumination. This solution-based precursor approach creates a new blueprint for the rational design and controlled synthesis of inorganic-organic hybrid materials.

Thiacalix[4]arene-supported kite-like heterometallic tetranuclear Zn(II)Ln(III)3 (Ln = Gd, Tb, Dy, Ho) complexes.

Four kite-like tetranuclear Zn(II)Ln(III)3 (Ln= Gd 1, Tb 2, Dy 3, Ho 4) clusters supported by p-tert-butylthiacalix[4]arene (H4BTC4A) have been prepared under solvothermal conditions and structurally characterized by single crystal X-ray diffraction and powder X-ray diffraction (PXRD). In the structures of these four complexes, each of them is capped by two tail-to-tail p-tert-butylthiacalix[4]arene molecules to form a bent sandwich-like unit. The photoluminescent analyses reveal that the H4BTC4A is an efficient sensitizer for Tb(3+) ions in 2. The magnetic properties of complexes 1-4 are also investigated, in which complex 3 exhibits slow magnetization relaxation typical for single molecule magnets.

A viologen-based Cd(II) coordination polymer as a multifunctional platform for photochromism, chemochromism and a broad range of fluorescence pH sensing.

A multi-responsive Cd(II) coordination polymer (1) has been constructed by introducing a viologen derivative as both the framework backbone and ligand side pendant. Notably, compound 1 exhibits intriguing properties, including photochromism, methanol-assisted photochromism and chemochromism to ammonia. Furthermore, compound 1 also displays fluorescence pH sensing ability in a wide pH range.

Chlorine-induced assembly of a cationic coordination cage with a µ5-carbonato-bridged Mn(II)24 core.

Chlorine caged in! The chlorine-induced assembly of six shuttlecock-like tetranuclear Mn(II) building blocks generated in situ based on p-tert-butylthiacalix[4]arene and facial anions gave rise to a novel truncated distorted octahedral cationic coordination cage with a µ(5)-carbonato-bridged Mn(II)(24) core.

A series of octanuclear-nickel(II) complexes supported by thiacalix[4]arenes.

A series of discrete complexes, [Ni(8)(BTC4A)(2)(µ(6)-CO(3))(2)(µ-CH(3)COO)(4)(dma)(4)]·H(2)O (1), [Ni(8)(BTC4A)(2)(µ(6)-CO(3))(2)(µ-Cl)(2)(µ-HCOO)(2)(dma)(4)]·2DMF·2CH(3)CN (2), [Ni(8)(PTC4A)(2) (µ(6)-CO(3))(2)(µ-CH(3)COO)(4)(dma)(4)]·DMF (3), and [Ni(8)(PTC4A)(2)(µ(6)-CO(3))(2)(µ-OH)(µ-HCOO)(3) (dma)(4)] (4) (p-tert-butylthiacalix[4]arene = H(4)BTC4A, p-phenylthiacalix[4]arene = H(4)PTC4A, dma = dimethylamine, and DMF = N,N'-dimethylformamide), have been prepared under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction analyses, powder XRD, and IR spectroscopy. These four complexes are stacked by dumbbell-like building blocks with one chairlike octanuclear-nickel(II) core, which is capped by two thiacalix[4]arene molecules and connected by two in situ generated carbonato anions and different auxiliary anions. This work implied that not only the solvent molecules but also the upper-rim groups of thiacalix[4]arenes have significant effects on the self-assembly of the dumbbell-like building blocks. The magnetic properties of complexes 1-4 were examined, indicating strong antiferromagnetic interactions between the nickel(II) ions in the temperature range of 50-300 K.

Visible and NIR photoluminescence properties of a series of novel lanthanide-organic coordination polymers based on hydroxyquinoline-carboxylate ligands.

A series of novel two-dimensional (2D) lanthanide coordination polymers with 4-hydroxyquinoline-2-carboxylate (H(2)hqc) ligands, [Ln(Hhqc)(3)(H(2)O)](n)·3nH(2)O (Ln = Eu (1), Tb (2), Sm (3), Nd (4), and Gd (5)) and [Ln(Hhqc)(ox)(H(2)O)(2)](n) (Ln = Eu (6), Tb (7), Sm (8), Tm (9), Dy (10), Nd (11), Yb (12), and Gd (13); H(2)ox = oxalic acid), have been synthesized under hydrothermal conditions. Complexes 1-5 are isomorphous, which can be described as a two-dimensional (2D) hxl/Shubnikov network based on Ln(2)(CO(2))(4) paddle-wheel units, and the isomorphous complexes 6-13 feature a 2D decker layer architecture constructed by Ln-ox infinite chains cross-linked alternatively by bridging Hhqc(-) ligands. The room-temperature photoluminescence spectra of complexes Eu(III) (1 and 6), Tb(III) (2 and 7), and Sm(III) (3 and 8) exhibit strong characteristic emissions in the visible region, whereas Nd(III) (4 and 11) and Yb(III) (12) complexes display NIR luminescence upon irradiation at the ligand band. Moreover, the triplet state of H(2)hqc matches well with the emission level of Eu(III), Tb(III), and Sm(III) ions, which allows the preparation of new optical materials with enhanced luminescence properties.

Cationic coordination polymers with thirteen-fold interpenetrating dia networks: selective coloration and ion-controlled photochromism.

A novel Cd-based cationic coordination polymer (Cd-CCP) constructed using viologen derivatives, which exhibits an unusual thirteen-fold interpenetrating diamondoid network, has been synthesized. Notably, Cd-CCP displays selective and naked-eye distinguished coloration and ion-controlled photochromism towards halide anions.

A Sm-MOF/GO nanocomposite membrane for efficient organic dye removal from wastewater.

The instability of graphene oxide (GO) membranes in aqueous solutions restricts their application in wastewater treatment through the membrane separation technology. In this work, a nanocomposite membrane (Sm-MOF/GO) composed of samarium metal-organic frameworks (Sm-MOFs) and GO nanosheets was successfully fabricated via the filtration of the corresponding Sm-MOF/GO dispersions. The in situ growth of Sm-MOF with aqueous stability on the GO sheets prevented the adjacent GO layers from expanding in aqueous solutions, thus endowing the prepared Sm-MOF/GO membrane with a stable membrane skeleton structure. Besides, the successful loading of Sm-MOF enlarged the layer space of the composite membrane, which was beneficial for higher permeance. The optimization of the Sm-MOF loading contents was also investigated to prepare M-X (where X represents the mass ratio of the MOF raw material to the total mass of the reactants). Subsequently, the fabricated M-0.31 possessed a high permeance of 26 L m-2 h-1 bar-1, which was 3 times higher than that of a pure GO membrane; moreover, high rejections (>91%) to rhodamine B and methylene blue were obtained. After continuous 5.5 h filtration, the excellent rejection was still maintained as expected, indicating the long-term stability of M-0.31.

Two novel lead-based coordination polymers for luminescence sensing of anions, cations and small organic molecules.

Two novel lead-based coordination polymers, namely [Pb(cbdcp)]·0.5H2O·0.5CH3OH (1) and [Pb(cbdcp)] (2), have been solvothermally constructed by using a zwitterionic ligand 4-carboxy-1-(3,4-dicarboxy-benzyl)-pyridinium chloride (abbreviated as H3cbdcpCl). Compound 1 has a three-dimensional framework displaying a valence-bonded SrAl2 topology with the 42·63·8 symbol, while compound 2 has a two-dimensional sheet structure that can be simplified into a three-dimensional ππ interaction-connected topology with the {44·62}2{48·615·85} symbol. Notably, compound 1 proved to be a promising potential luminescent sensor capable of selectively detecting anions, cations and small organic molecules, especially Cr2O72-, CrO42-, Fe3+ and nitrobenzene.

1D Infinite silver(i) chains reside in the big cavities built by the novel p-sulfonatocalix[4]arene-trisilver blocks.

A novel luminescent inclusion complex, {[(C4AS)(2)Ag(3)(mu-2,2'-bpy)(2)(2,2'-bpy)(2)] [Ag(5)(mu-2,2'-bpy)(4)(2,2'-bpy)(4)].20H(2)O}(n) () (2,2'-bpy = 2,2'-bipyridine, C4AS = p-sulfonatocalix[4]arene), with an unusual framework is reported: the parallel 1D infinite silver(i) chains separated by the water belts reside in the big cavities of the p-sulfonatocalix[4]arene-trisilver blocks.

A cyano-bridged Cu(i)-based organic framework coupled with the C-C bond cleavage of acetonitrile for selective and sensitive sensing of Fe3+ ions.

A cyano-bridged Cu(i) organic framework based on [Cu6(CN)6]n was synthesized, in which cyano anions were generated in situ from the C-C bond cleavage of acetonitrile. The as-synthesized compound displays orange-red luminescence and is further proven to be a promising Fe3+ luminescent sensor with high selectivity and sensitivity.

Extremely stable europium-organic framework for luminescent sensing of Cr2O72- and Fe3+ in aqueous systems.

Three novel 3D lanthanide-organic frameworks, namely [Ln2L(1,3-bdc)3]·5H2O (Ln: Eu, Sm and Dy), with a 412·63 topology based on a zwitterionic ligand, 4-bis(4-carboxylatopyridinium-1-methylene)benzene dichloride (H2LCl2), and 1,3-benzene dicarboxylic acid (1,3-H2bdc) have been synthesized hydrothermally. Notably, the Ln-MOFs are extremely stable in an aqueous system and are capable of resisting acids or bases over a wide pH range from 3 to 11. Meanwhile, an Eu-MOF is further proven to be a promising dual sensor in an aqueous system toward Cr2O72- and Fe3+.

Transcriptomic and metabolomic profiles of Chinese citrus fly, Bactrocera minax (Diptera: Tephritidae), along with pupal development provide insight into diapause program.

The Chinese citrus fly, Bactrocera minax (Enderlein), is a devastating citrus pest in Asia. This univoltine insect enters obligatory pupal diapause in each generation, while little is known about the course and the molecular mechanisms of diapause. In this study, the course of diapause was determined by measuring the respiratory rate throughout the pupal stage. In addition, the variation of transcriptomic and metabolomic profiles of pupae at five developmental stages (pre-, early-, middle-, late-, and post-diapause) were evaluated by next-generation sequencing technology and 1H nuclear magnetic resonance spectroscopy (NMR), respectively. A total of 4,808 genes were significantly altered in ten pairwise comparisons, representing major shifts in metabolism and signal transduction as well as endocrine system and digestive system. Gene expression profiles were validated by qRT-PCR analysis. In addition, 48 metabolites were identified and quantified by 1H NMR. Nine of which significantly contributed to the variation in the metabolomic profiles, especially proline and trehalose. Moreover, the samples collected within diapause maintenance (early-, middle-, and late-diapause) only exhibited marginal transcriptomic and metabolomic variation with each other. These findings greatly improve our understanding of B. minax diapause and lay the foundation for further pertinent studies.

De novo Transcriptome Analysis of Chinese Citrus Fly, Bactrocera minax (Diptera: Tephritidae), by High-Throughput Illumina Sequencing.

The Chinese citrus fly, Bactrocera minax (Enderlein), is one of the most devastating pests of citrus in the temperate areas of Asia. So far, studies involving molecular biology and physiology of B. minax are still scarce, partly because of the lack of genomic information and inability to rear this insect in laboratory. In this study, de novo assembly of a transcriptome was performed using Illumina sequencing technology. A total of 20,928,907 clean reads were obtained and assembled into 33,324 unigenes, with an average length of 908.44 bp. Unigenes were annotated by alignment against NCBI non-redundant protein (Nr), Swiss-Prot, Clusters of Orthologous Groups (COG), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes Pathway (KEGG) database. Genes potentially involved in stress tolerance, including 20 heat shock protein (Hsps) genes, 26 glutathione S-transferases (GSTs) genes, and 2 ferritin subunit genes, were identified. These genes may play roles in stress tolerance in B. minax diapause stage. It has previously been found that 20E application on B. minax pupae could avert diapause, but the underlying mechanisms remain unknown. Thus, genes encoding enzymes in 20E biosynthesis pathway, including Neverland, Spook, Phantom, Disembodied, Shadow, Shade, and Cyp18a1, and genes encoding 20E receptor proteins, ecdysone receptor (EcR) and ultraspiracle (USP), were identified. The expression patterns of 20E-related genes among developmental stages and between 20E-treated and untreated pupae demonstrated their roles in diapause program. In addition, 1,909 simple sequence repeats (SSRs) were detected, which will contribute to molecular marker development. The findings in this study greatly improve our genetic understanding of B. minax, and lay the foundation for future studies on this species.

RNA interference of a trehalose-6-phosphate synthase gene reveals its roles during larval-pupal metamorphosis in Bactrocera minax (Diptera: Tephritidae).

Trehalose is the major blood sugar in insects, which plays a crucial role as an instant source of energy and the starting substrate for chitin biosynthesis. In insects, trehalose is synthesized by catalysis of an important enzyme, trehalose-6-phosphate synthase (TPS). In the present study, a trehalose-6-phosphate synthase gene from Bactrocera minax (BmTPS) was cloned and characterized. BmTPS contained an open reading frame of 2445 nucleotides encoding a protein of 814 amino acids with a predicted molecular weight of 92.05kDa. BmTPS was detectable in all developmental stages of Bactrocera minax and expressed higher in the final- (third-) instar larvae. Tissue-specific expression patterns of BmTPS showed that it was mainly expressed in the fat body. The 20-hydroxyecdysone (20E) induced the expression of BmTPS and three genes in the chitin biosynthesis pathway. Moreover, injection of double-stranded RNA into third-instar larvae successfully silenced the transcription of BmTPS in B. minax, and thereby decreased the activity of TPS and trehalose content. Additionally, silencing of BmTPS inhibited the expression of three key genes in the chitin biosynthesis pathway and exhibited 52% death and abnormal phenotypes. The findings demonstrate that BmTPS is indispensable for larval-pupal metamorphosis. Besides, the establishment of RNAi experimental system in B. minax would lay a solid foundation for further investigation of molecular biology and physiology of this pest.

2D sheet-like architectures constructed from main-group metal ions, 4,4'-bpno and 1,2-alternate p-sulfonatothiacalix[4]arene.

Two novel 2D sheet-like complexes 1 and 2 have been prepared by reaction of p-sulfonatothiacalix[4]arene (TC4AS) with main-group metal ions (lead(II) or barium(II)) and 4,4'-bipyridine-N,N'-dioxide (4,4'-bpno). In both complexes 1 and 2, TC4AS molecules prefer 1,2-alternate conformation, forming 2D sheet-like layers in the presence of divalent ions and 4,4'-bpno ligand. The layers extend to 3D architectures via strong hydrogen bonding interactions. In addition, complexes 1 and 2 are thermally stable up to ca. 335 and 305 °C, respectively. It seems that the strong hydrogen bonds between the sheet-like layers impart the extraordinarily high degrees of stability to the structures. Further analysis indicates that complexes 1 and 2 are significantly different: (a) the divalent ions have different coordination environments due to the nature of the different ions; (b) TC4AS within complexes 1 and 2 connects to four Pb(II) or six Ba(II) ions, respectively; (c) 4,4'-bpno shows different connection modes; (d) in the solid state, complex 1 exhibits intense orange luminescence with triexponential decays, while complex 2 does not exhibit any obvious luminescence at cryogenic temperatures.