The selective aerobic oxidative coupling of amines under mild conditions is an important laboratory and commercial procedure yet a great challenge. In this work, a porphyrinic metal-organic ...framework, PCN-222, was employed to catalyze the reaction. Upon visible light irradiation, the semiconductor-like behavior of PCN-222 initiates charge separation, evidently generating oxygen-centered active sites in Zr-oxo clusters indicated by enhanced porphyrin π-cation radical signals. The photogenerated electrons and holes further activate oxygen and amines, respectively, to give the corresponding redox products, both of which have been detected for the first time. The porphyrin motifs generate singlet oxygen based on energy transfer to further promote the reaction. As a result, PCN-222 exhibits excellent photocatalytic activity, selectivity and recyclability, far superior to its organic counterpart, for the reaction under ambient conditions
combined energy and charge transfer.
In the hydrothermal crystallization of zeolites from basic media, hydroxide ions (OH⁻) catalyze the depolymerization of the aluminosilicate gel by breaking the Si,AI–O–Si,AI bonds and catalyze the ...polymerization of the aluminosilicate anions around the hydrated cation species by remaking the Si,AI–O–Si,AI bonds. We report that hydroxyl free radicals (•OH) are involved in the zeolite crystallization under hydrothermal conditions. The crystallization processes of zeolites—such as Na–A, Na–X, NaZ–21, and silicalite-1—can be accelerated with hydroxyl free radicals generated by ultraviolet irradiation or Fenton's reagent.
Depression is a devastating disorder with a combination of diverse symptoms such as low self-esteem, lack of motivation, anhedonia, loss of appetite, low energy, and discomfort without a clear cause. ...Depression has been suggested to be the result of maladaptive changes in specific brain circuits. Recently, the lateral habenula (LHb) has emerged as a key brain region in the pathophysiology of depression. Increasing evidence from rodent, non-human primate and human studies indicates that the aberrant activity of the LHb is associated with depressive symptoms such as helplessness, anhedonia, and excessive negative focus. Revealing the molecular, cellular and circuit properties of the LHb will help explain how abnormalities in LHb activity are linked to depressive disorders, and shed light on developing novel strategies for depression treatment.
Friend leukemia virus integration 1 (FLI1), an ETS transcription factor family member, acts as an oncogenic driver in hematological malignancies and promotes tumor growth in solid tumors. However, ...little is known about the mechanisms underlying the activation of this proto-oncogene in tumors.
Immunohistochemical staining showed that FLI1 is aberrantly overexpressed in advanced stage and metastatic breast cancers. Using a CRISPR Cas9-guided immunoprecipitation assay, we identify a circular RNA in the FLI1 promoter chromatin complex, consisting of FLI1 exons 4-2-3, referred to as FECR1.Overexpression of FECR1 enhances invasiveness of MDA-MB231 breast cancer cells. Notably, FECR1 utilizes a positive feedback mechanism to activate FLI1 by inducing DNA hypomethylation in CpG islands of the promoter. FECR1 binds to the FLI1 promoter in cis and recruits TET1, a demethylase that is actively involved in DNA demethylation. FECR1 also binds to and downregulates in trans DNMT1, a methyltransferase that is essential for the maintenance of DNA methylation.
These data suggest that FECR1 circular RNA acts as an upstream regulator to control breast cancer tumor growth by coordinating the regulation of DNA methylating and demethylating enzymes. Thus, FLI1 drives tumor metastasis not only through the canonical oncoprotein pathway, but also by using epigenetic mechanisms mediated by its exonic circular RNA.
In this study, a sensitive infrared photodetector (IRPD) composed of a germanium nanocones (GeNCs) array and PdSe2 multilayer is presented, which is obtained by a straightforward selenization ...approach. The as‐assembled PdSe2/GeNCs hybrid heterojunction exhibits obvious photovoltaic behavior to 1550 nm illumination, which renders the IRPD a self‐driven device without external power supply. Further device analysis reveals that the PdSe2/GeNCs hybrid based IRPD exhibits high sensitivity to 1350, 1550, and 1650 nm illumination with excellent stability and reproducibility. The responsivity and external quantum efficiency is as high as 530.2 mA W−1 and 42.4%, respectively. Such a relatively good device performance is related to the strong light trapping effect of GeNCs array, according to the theoretical simulation based on finite‐difference time‐domain. It is also found that the IRPD shows an abnormal sensitivity to IR illumination with a wavelength of 2200 nm. Finally, the present individual IRPD can also record the simple “F” image produced by 1550 nm, suggesting the promising application of the PdSe2/GeNCs hybrid device in future infrared optoelectronic systems.
A highly sensitive infrared light photo‐detector is fabricated by transferring multilayer PdSe2 on a germanium nanocones array with a strong light‐trapping effect. The as‐assembled PdSe2/GeNCs hybrid heterojunction devices can also record simple near‐infrared images.
The photogeneration of stable radicals is important but still challenging in the field of optical switching, displays, and other devices. Herein, crystalline 9-anthracene carboxylic acid (
9-AC
) and ...a mononuclear complex constructed from this ligand were for the first time discovered to show radical-induced photochromism and photomagnetism after Xe lamp light irradiation. This study finds a simple radical-actuated photochromic molecule for constructing a novel system of photochromic materials.
The crystalline 9-anthracene carboxylic acid and the constructed mononuclear complex were for the first time discovered to show radical-induced photochromism and photomagnetism after Xe lamp light irradiation.
Carboazidation of alkenes and alkynes holds the promise to construct valuable molecules directly from chemical feedstock therefore is significantly important. Although a few examples have been ...developed, there are still some unsolved problems and lack of universal methods for carboazidation of both alkenes and alkynes. Here we describe an iron-catalyzed rapid carboazidation of alkenes and alkynes, enabled by the oxidative radical relay precursor t-butyl perbenzoate. This strategy enjoys success with a broad scope of alkenes under mild conditions, and it can also work with aryl alkynes which are challenging substrates for carboazidation. A large number of diverse structures, including many kinds of amino acid precursors, fluoroalkylated vinyl azides, other specific organoazides, and 2H-azirines can be easily produced.
As promising photoresponsive materials and potential smart materials, hybrid photochromic materials (HPMs), especially for crystalline HPMs (CHPMs), have been broadly explored for their potential in ...inheriting the merits of each constituents, and intriguing photomodulated functionality. Hitherto, the photoresponsive functionality in explored CHPMs mainly concentrate on dyad combination. By contrast, triple or quadruple photoresponsive properties are very rare because of the limited compatibility of multiple photoresponsive functionality in a single system. In this work, the electron‐transfer (ET) and crystal engineering strategies were utilized to predesign CHPMs with multiple photoresponsive properties via the collaboration of paramagnetic metal ion (Dy3+), electron‐donor (ED) ligand (benzene‐1,2,3‐tricarboxylic acid, H3BTA) and electron‐acceptor (EA) ligand (1,10‐phenanthroline, phen). The resulting complex Dy(BTA)(phen)2⋅2H2O (1) shows hybrid chain with the intrachain Dy3+ ions bridged and chelated by tricarboxylate and phen ligands, respectively. After photostimuli, the ET between tricarboxylate and phen results in photogenerated radicals and the resultant quadruple photoresponsive properties. Considering the abundant resources of paramagnetic metal ions, ED‐ and EA‐ligands, this work provides a general method to construct CHPMs with multiple photoresponsive performances via the collaboration of each unit under the guidance of ET and crystal engineering strategies.
A crystalline hybrid material is reported with quadruple photoresponsive functionality, which shows photochromism, photomodulated fluorescence, magnetism, and second‐order nonlinear optical properties. This work provides a general method to construct hybrid photochromic materials with multiple photoresponsive performances.
Exploitation of room temperature (RT) photochromism and photomagnetism to induce single-molecule magnet (SMM) behavior has potential applications toward optical switches and magnetic memories, and ...remains a tremendous challenge in the development of new bulk magnets. Herein, a series of chain complexes Ln3(H–HEDP)3(H2–HEDP)3·2H3–TPT·H4–HEDP·10H2O (QDU-1; Ln = Dy (QDU-1(Dy)), Gd (QDU-1(Gd)), and Y (QDU-1(Y)); HEDP = hydroxyethylidene diphosphonate; TPT = 2,4,6-tri(4-pyridyl)-1,3,5-triazine) were synthesized by solvothermal reactions. All the compounds exhibited reversible photochromic and photomagnetic behaviors via UV light irradiation at RT, induced by the photogenerated radicals via a photoinduced electron transfer (PET) mechanism. More importantly, the PET process induced significant variations in magnetic interactions for the Dy(III) congener. Strong ferromagnetic coupling with remarkably slow magnetic relaxation without applied dc fields was observed between DyIII ions and photogenerated O• radicals, showing SMM behavior after RT illumination. For the first time, we observed the reversible RT photochromism and photomagnetism in the lanthanide-based materials. This work realized the radicals-actuated on/off SMM behavior via RT light irradiation, providing a new strategy for constructing the light-induced SMMs.
Display omitted
•The GO/MOFs nanocomposites can be used as applicable nanocontainers.•Inhibitor-encapsulated GO/MOFs nanocontainers exhibit both passive and active protecting properties.•The method ...of preparing GO/MOFs nanocontainers is facile and versatile by just one-pot reaction.
In this work, metal organic frameworks (MOFs) are in situ growing on the graphene oxide (GO) sheets to fabricate GO/MOFs nanocontainers for both active and passive corrosion protection. ZIF-8 and UiO-66 are chosen as two classic examples to synthesize GO/MOFs nanocontainers encapsulating benzotriazole (BTA) embedded in polyvinyl butyral (PVB) resin. The composite coatings are successfully utilized in protecting pure copper and archaized bronze, exhibiting both active and passive protecting properties. The passive protection capability is ensured by good barrier performance of GO, and the active prevention property is provided by the pH-stimulated release of embedded inhibitors from the composite nanocontainers.
PDF
