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Circular RNAs (circRNAs) have been reported to participate in the development of various diseases. In this study, we investigated the potential mechanism underlying the role of circRNAs in atherosclerosis. Human umbilical vein endothelial cells (HUVECs) were treated with 100µg/mL oxidized low-density lipoprotein (ox-LDL) to simulate atherosclerosis. We observed that hsa_circ_0006867 (circ_0006867), a circRNA markedly increased in ox-LDL-treated endothelial cells, acted as a molecular sponge of miR-499a-3p and regulated its expression. This interaction led to changes in the downstream target gene ADAM10, thus affecting cell apoptosis and migration. Thus, our study suggests that circ_0006867 regulates ox-LDL-induced endothelial injury via the circ_0006867/miR-499a-3p/ADAM10 axis, indicating its potential as an exploitable therapeutic target for atherosclerosis.
RESUMO
Cyclometalated Ir(iii) complexes [Ir(dfppy)2(qbiH)](PF6) (1), [Ir(dfppy)2(qbim)](PF6)·H2O (2), [Ir(dfppy)2(qbio)](PF6) (3) and [Ir(dfppy)2(qbi)] (4) have been designed and prepared, in which the N^N ligands qbiH, qbim and qbio incorporate different substituent groups R on their imidazole units (H atom, CH3 group and n-C8H17 group, respectively) in order to explore the influence of the substituent groups R and the protonation/deprotonation state of imidazole units in these Ir(iii) complexes on their structures and luminescence behaviors. Crystal structures indicate that an {Ir(dfppy)2}+ unit is coordinated by neutral ligands qbiH in 1, qbim in 2 and qbio in 3, while a qbi- anion in 4. These Ir(iii) complexes show clearly different molecular stacking modes. In compound 1, neighboring [Ir(dfppy)2(qbiH)]+ cations are linked into a supramolecular chain through ππ stacking interactions between adjacent dfppy-/qbiH ligands. In 2 and 4, two neighboring iridium complex units connect each other through ππ stacking interactions between dfppy- ligands in the former, while between qbi- ligands in the latter, forming supramolecular dimers. Compared to 1, 2 and 4, compound 3 only exhibits intermolecular van der Waals interactions. At room temperature, these Ir(iii) complexes in CH2Cl2 reveal phosphorescence with a mixing of 3MLCT and 3LC characters, emissions at 558 and 585 nm for 1, 572 (or 573) and 600 nm for 2 and 3, and 546 nm for 4. Compared to 1-3, compound 4 displays relatively weak luminescence intensity. Interestingly, upon addition of NEt3/TFA, both 1 and 4 in CH2Cl2 can switch their luminescence between strong emission at 558 nm and weak emission at 546 nm, due to their acid-/base-induced structural interconversion between the protonation state and the deprotonation state of the qbiH ligand. The emissions of 1-4 in the solid state reveal different degrees of the red shift compared to their corresponding emissions in CH2Cl2, the broad emission bands at 542, 572 and 611 nm for 1, 553, 581 and 612 nm for 2, 544, 578 and 630 nm for 3, and 595 and 633 nm for 4. Based on the crystal structures of 1-4, this work discusses the luminescence modulation of these Ir(iii) complexes by varying their substituent groups or the protonation/deprotonation state of the imidazole units.
RESUMO
Heteroleptic complexes [Ir(dfppy)2(BrL)]·3CH3OH () and [Pt(dfppy)(BrL)]·CH3OH () have been prepared based on the same ligands including bisthienylethene BrLH and dfppyH = (2-(2,4-difluorophenyl)-pyridine). Complexes and reveal distinct crystal structures. The BrL(-) anion uses its phenol-imidazole moiety to coordinate with an {Ir(dfppy)2}(+) unit in the former, while with a {Pt(dfppy)}(+) unit in the latter. Neighboring [Ir(dfppy)2(BrL)]/[Pt(dfppy)(BrL)] molecules are connected through extensive hydrogen bonds and aromatic stacking interactions, thus forming a supramolecular chain structure in , and a layer structure in . Upon irradiation with 380 nm light, compound shows photochromic behavior in CH2Cl2, with a color change from nearly colorless to light green. However, no photochromism was observed in compound . At room temperature, compound reveals phosphorescence with a predominant (3)MLCT character both in CH2Cl2 solution (emissions at 495 and 513 nm) and in the solid state (emission at 524 nm). Compound exhibits phosphorescence with a predominant (3)LC character in CH2Cl2 solution (emission at 508 nm), but it is almost non-luminescent in the solid state. Our experimental results demonstrate that the metal centers in and could significantly influence their structures, photochromism, and luminescence behaviors.
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Molecular assembly of bisthienylethene Th2im (1) and [ReCl6]2− anions leads to the complex (Th2imH)2[ReCl6] (2), in which a [ReCl6]2(-) anion connects two equivalent Th2imH+ cations through Clâ¯N/C hydrogen bonds. Crystal structures of 1 and 2 indicate that two thiophene groups of each Th2im/Th2imH+ molecule adopt a photoactive antiparallel conformation. Thus, two compounds show crystalline-phase photochromism (CPP), i.e. reversible structural transformation between the open form and the closed form upon alternately irradiating the sample with UV light (365 nm) and visible light (574 nm for 1, 624 nm for 2). It was found that the CPP behaviors of 1 and 2 could regulate their luminescence and/or magnetic properties. Their solid-state emissions (433, 448, 482, 531 and 570 nm for 1, and 460, 489, 535 and 593 nm for 2) exhibited weaker intensities after UV irradiation with 365 nm light. Besides CPP and luminescence, compound 2 shows field-induced slow magnetic relaxation. Before and after UV irradiation, this compound revealed different magnetic behaviors, including the differences in the shape of the χMT vs. T plot, D parameter, and the values of the relaxation barrier Ueff and the preexponential factor τ0.
RESUMO
2-(Anthracenyl)-4,5-bis(2,5-dimethyl(3-thienyl))-1H-imidazole (anbdtiH) has been synthesized. Its three solid-state structures, anbdtiH·CH3Cl (1), anbdtiH·2CH3OH (2) and anbdtiH2·CF3COO·CH3OH·H2O (3), have been constructed by skillfully choosing CHCl3 or CH3OH as the solvent and using or not using CF3COOH, with the aim of modifying the intermolecular hydrogen bonds and/or π···π stacking interactions. The three distinct structures show significantly different solid-state luminescence behaviors, an orange-red emission at 603 nm for 1, a blue emission at 453 nm for 2, and a green emission at 533 nm for 3. Upon grinding, these emission wavelengths exhibit evident variations, a blue-shift of Δλ = 83 nm for 1, a red-shift of Δλ = 20 nm for 2, and a blue-shift of Δλ = 54 nm for 3. The emission color of 1 can be reversibly switched between orange-red and green upon regulation of the intermolecular (N-H)imidazole···Nimidazole hydrogen bonds by a grinding-heating process. Moreover, compound 3 can undergo a solid-state [4π + 4π] photodimerization reaction upon irradiation with sunlight, forming 3-dimer. Based on the crystal structures of 1-3, this work discusses the relationship between the molecular stacking mode and the luminescence behavior/photochemical reactivity.
RESUMO
Complexes [Ir(dfppy)2(pbdtiH)](PF6)·2CHCl3 (1-H) and [Ir(dfppy)2(pbdti)] (1) were synthesized by the reaction of bisthienylethene pbdtiH and an [Ir(dfppy)2Cl]2 dimer under neutral and basic conditions, respectively. Thus, the {Ir(dfppy)2}(+) unit is coordinated by pbdtiH in 1-H, and by pbdti(-) in 1, which are confirmed by their crystal structures. The structures of 1-H and 1 could be interconverted in solution, upon alternately adding NEt3 and TFA, thus resulting in reversible luminescence switching between the on-state of 1-H and the off-state of 1 at room temperature. In addition, both 1-H and 1 show solid-state luminescence, with a broad emission at 534 nm and 525 nm, respectively. The free pbdtiH ligand shows photochromic behavior in CH2Cl2 solution. However, no photochromism has been observed in 1-H and 1, indicating that the coordination of the pbdtiH/pbdti(-) ligand to the {Ir(dfppy)2}(+) unit could suppress their photochromic behaviors.
