Advances towards Cell-Specific Gene Transfection: A Small-Molecule Approach Allows Order-of-Magnitude Selectivity

A transfection vector that can home in on tumors is reported. Whereas previous vectors that allow moderately cell selective gene transfection used larger systems, this small-molecule approach paved the way for precise structure-activity relationship optimization. For this, biotin, which mediates cell selectivity, was combined with the potent DNA-binding motif tetralysine-guanidinocarbonypyrrol via a hydrophilic linker, thus enabling SAR-based optimization. The new vector mediated biotin receptor (BR)-selective transfection of cell lines with different BR expression levels. Computer-based analyses of microscopy images revealed a preference of one order of magnitude for the BR-positive cell lines over the BR-negative controls.     

Efficient Gating of Ion Transport in Three‐Dimensional Metal–Organic Framework Sub‐Nanochannels with Confined Light‐Responsive Azobenzene Molecules

1D nanochannels modified with responsive molecules are fabricated to replicate gating functionalities of biological ion channels, but gating effects are usually weak because small molecular gates cannot efficiently block the large channels in the closed states. Now, 3D metal–organic framework (MOF) sub‐nanochannels (SNCs) confined with azobenzene (AZO) molecules achieve efficient light‐gating functionalities. The 3D MOFSNCs consisting of a MOF UiO66 with ca. 9–12 Å cavities connected by ca. 6 Å triangular windows work as angstrom‐scale ion channels, while confined AZO within the MOF cavities function as light‐driven molecular gates to efficiently regulate the ion flux. The AZO‐MOFSNCs show good cyclic gating performance and high on–off ratios up to 17.8, an order of magnitude higher than ratios observed in conventional 1D AZO‐modified nanochannels (1.3–1.5). This work provides a strategy to develop highly efficient switchable ion channels based on 3D porous MOFs and small responsive molecules.     

旋涂法制备WO3薄膜电致变色性能

"智能窗"大规模推广顺应可持续发展潮流,三氧化钨(WO_3)是生产"智能窗"的一种重要电致变色材料,但调控WO_3薄膜电致变色性能机制仍待进一步研究。采用旋涂法制备WO_3薄膜,重点研究了溶液浓度和旋涂次数对调控WO_3薄膜电致变色性能的影响。通过表面轮廓仪测量薄膜厚度,X射线衍射(XRD)测量薄膜结晶情况,原子力显微镜(AFM)和扫描电子显微镜(SEM)分析薄膜表面形貌,光谱仪测量薄膜初始态、着色态和褪色态的透射率。实验结果表明,随着溶液浓度增加(0. 2～1. 0 mol/L),薄膜厚度从9. 7 nm增加到33. 3 nm,透射率调制能力从0%提升到37. 0%;多次旋涂薄膜厚度线性增长,线性拟合优度(R~2)达0. 98,5次旋涂后透射率调制能力达51. 3%。改变溶液浓度和旋涂次数都是调控薄膜透射率调制能力的有效手段,精准调控薄膜透射率调制能力对设计不同应用场景的电致变色器件具有重大意义。     

Rational Design of a Uranyl Metal–Organic Framework for the Capture and Colorimetric Detection of Organic Dyes

A new uranyl containing metal–organic framework, RPL-1 : [(UO₂)₂(C₂₈H₁₈O₈)] ^. H₂O (RPL for Radiochemical Processing Laboratory), was prepared, structurally characterized, and the solid-state photoluminescence properties explored. Single crystal X-ray diffraction data reveals the structure of RPL - 1 consists of two crystallographically unique three dimensional, interpenetrating nets with a 4,3-connected tbo topology. Each net contains large pores with an average width of 22.8 Å and is formed from monomeric, hexagonal bipyramidal uranyl nodes that are linked via 1,2,4,5-tetrakis(4-carboxyphenyl)benzene (TCPB) ligands. The thermal and photophysical properties of RPL-1 were investigated using thermogravimetric analysis and absorbance, fluorescence, and lifetime spectroscopies. The material displays excellent thermal stability and temperature dependent uranyl and TCPB luminescence. The framework is stable in aqueous media and due to the large void space (constituting 76 % of the unit cell by volume) can sequester organic dyes, the uptake of which induces a visible change to the color of the material.     

A novel nano‐size lanthanum metal–organic framework based on 5‐amino‐isophthalic acid and phenylenediamine: Photoluminescence study and sensing applications

In this paper, a novel lanthanum metal–organic framework La‐MOF was prepared via hydrothermal and reflux methods. The La‐MOF was achieved through the reaction of a 5‐amino‐isophthalic acid with 1, 2‐phenylenediamine and lanthanum chloride. The prepared La‐MOF structure was confirmed by XRD, mass spectrometry, IR, UV–Vis and elemental analysis, whereas the size, and morphology was examined by FE‐SEM/EDX and HR‐TEM. The results indicated that the La‐MOF prepared via both methods have the same structure and composition. Meanwhile, the MOF yield, reaction time, morphology, physiochemical and sensing properties were highly depended on the used preparation method. The photoluminescence (PL) study was carried out for the La‐MOF, and the results showed that La‐MOF exhibits strong emission at 558 nm after excitation at 369 nm. Moreover, the PL data indicating that the La‐MOF has highly selective sensing properties for iron (III) competing with different metal ions. The Stern‐Völmer graph shows a linear calibration curve which achieved over a concentration range 1.0–500 μM of Fe³⁺ with a correlation coefficient, detection, and quantitation limits 0.998, 1.35 μM and 4.08 μM, respectively. According to the remarkable quenching of the PL intensity of La‐MOF using various concentrations of Fe³⁺, it was successfully used as a sensor for Fe³⁺detecting in different water resources (pure and waste) samples. The quenching mechanism was studied and it has a dynamic type and due to efficient energy transfer between the La‐MOF and Fe³⁺.     

Suppressing the environmental dependence of the open‐circuit voltage in inverted polymer solar cells through a radical polymer anodic modifier

Developing stable, readily‐synthesized, and solution‐processable transparent conducting polymers for interfacial modifying layers in organic photovoltaic (OPV) devices has become of great importance. Here, the radical polymer, poly(2,2,6,6‐tetramethylpiperidinyloxy methacrylate (PTMA), is shown to not affect the absorption of the well‐studied poly(3‐hexylthiophene) (P3HT) and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PCBM) active layer when incorporated into inverted OPV devices, as it is highly transparent in the visible spectrum due to the non‐conjugated nature of the PTMA backbone. The inclusion of this radical polymer as an anode‐modifying layer enhanced the open‐circuit voltage and short‐circuit current density values over devices that did not contain an anodic modifier. Importantly, devices fabricated with the PTMA interlayer had performance metrics that were time‐independent over the entire course of multiples days of testing after exposing the OPV devices to ambient conditions. Furthermore, these high performance values were independent of the metal used as the top electrode contact in the inverted OPV devices. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 311–316     

Deep desulfurization by oxidation using an active ionic liquid‐supported Zr metal–organic framework as catalyst

In this study, a Zr metal–organic framework (UIO‐66) was synthesized with zirconium tetrachloride and terephthalic acid using the solvent method. Then various masses of 1‐methylimidazolium‐3‐propylsulfonate hydrosulfate (PSMIMHSO₄) were supported on the UIO‐66 as catalysts, which were used for catalytic oxidative desulfurization. Sulfur removal using 400 mg of 40% PSMIMHSO₄ supported on the UIO‐66 of greater than 94% was obtained at 313 K for 20 min with an O/S molar ratio of 7:1. The results obtained in this work could provide useful information for the design of water‐stable metal–organic frameworks with permanent porosity in applications of catalytic oxidative desulfurization. Copyright © 2014 John Wiley & Sons, Ltd.     

Rational design of methacrylate monomers containing oxadiazole moieties for single‐layer organic light emitting devices

Methacrylate derived monomers functionalized with pendant oxadiazole moieties were synthesized and copolymerized with carbazole containing monomers to form polymers with electron and hole transporting fragments in the same molecule. Substituents on the oxidazole moiety were varied with the purpose of bandgap tuning and performance optimization when employed in single‐layer organic light emitting devices (OLED). Quantum mechanical calculations of the HOMO‐LUMO levels of the oxidazole derivatives were used to down‐select promising candidates for chemical synthesis and testing in single‐layer OLEDs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1663–1673     

Metal–Organic Framework/PVDF Composite Membranes with High H2 Permselectivity Synthesized by Ammoniation

Herein we report a new ammoniation‐based chemical modification strategy for synthesis of continuous and uniform metal–organic framework (MOF)/polyvinylidene fluoride (PVDF) membranes with attractive performance. Ammoniation can promote the support PVDF membrane to produce amino groups, form a nanoparticle structure, and be well cross‐linked; therefore, the high‐density heterogeneous nucleation sites for MOFs growth were provided and the thermal stability and chemical resistance of composite membranes can be greatly improved. The high‐quality layers of representative Cu‐BTC and ZIF‐8 were synthesized on the chemically modified PVDF membranes. By ammoniation, ZIF‐7 can even be grown under harsh synthetic conditions such as in DMF precursor solutions at 403 K. The fabricated MOF/PVDF composite membranes with excellent hollow fiber structures and enhanced structural stability exhibited high H₂ permselectivities for H₂/CO₂ and H₂/N₂.     

Continuous‐Flow Microwave Synthesis of Metal–Organic Frameworks: A Highly Efficient Method for Large‐Scale Production

Metal–organic frameworks are having a tremendous impact on novel strategic applications, with prospective employment in industrially relevant processes. The development of such processes is strictly dependent on the ability to generate materials with high yield efficiency and production rate. We report a versatile and highly efficient method for synthesis of metal–organic frameworks in large quantities using continuous flow processing under microwave irradiation. Benchmark materials such as UiO‐66, MIL‐53(Al), and HKUST‐1 were obtained with remarkable mass, space–time yields, and often using stoichiometric amounts of reactants. In the case of UiO‐66 and MIL‐53(Al), we attained unprecedented space–time yields far greater than those reported previously. All of the syntheses were successfully extended to multi‐gram high quality products in a matter of minutes, proving the effectiveness of continuous flow microwave technology for the large scale production of metal–organic frameworks.