A Cu3BHT-Graphene van der Waals Heterostructure with Strong Interlayer Coupling for Highly Efficient Photoinduced Charge Separation.

Two-dimensional van der Waals heterostructures (2D vdWhs) are of significant interest due to their intriguing physical properties critically defined by the constituent monolayers and their interlayer coupling. Synthetic access to 2D vdWhs based on chemically tunable monolayer organic 2D materials remains challenging. Herein, the fabrication of a novel organic-inorganic bilayer vdWh by combining π-conjugated 2D coordination polymer (2DCP, i.e., Cu3BHT, BHT = benzenehexathiol) with graphene is reported. Monolayer Cu3BHT with detectable µm2-scale uniformity and atomic flatness is synthesized using on-water surface chemistry. A combination of diffraction and imaging techniques enables the determination of the crystal structure of monolayer Cu3BHT with atomic precision. Leveraging the strong interlayer coupling, Cu3BHT-graphene vdWh exhibits highly efficient photoinduced interlayer charge separation with a net electron transfer efficiency of up to 34% from Cu3BHT to graphene, superior to those of reported bilayer 2D vdWhs and molecular-graphene vdWhs. This study unveils the potential for developing novel 2DCP-based vdWhs with intriguing physical properties.

Endosomal Arl4A attenuates EGFR degradation by binding to the ESCRT-II component VPS36.

Ligand-induced epidermal growth factor receptor (EGFR) endocytosis followed by endosomal EGFR signaling and lysosomal degradation plays important roles in controlling multiple biological processes. ADP-ribosylation factor (Arf)-like protein 4 A (Arl4A) functions at the plasma membrane to mediate cytoskeletal remodeling and cell migration, whereas its localization at endosomal compartments remains functionally unknown. Here, we report that Arl4A attenuates EGFR degradation by binding to the endosomal sorting complex required for transport (ESCRT)-II component VPS36. Arl4A plays a role in prolonging the duration of EGFR ubiquitinylation and deterring endocytosed EGFR transport from endosomes to lysosomes under EGF stimulation. Mechanistically, the Arl4A-VPS36 direct interaction stabilizes VPS36 and ESCRT-III association, affecting subsequent recruitment of deubiquitinating-enzyme USP8 by CHMP2A. Impaired Arl4A-VPS36 interaction enhances EGFR degradation and clearance of EGFR ubiquitinylation. Together, we discover that Arl4A negatively regulates EGFR degradation by binding to VPS36 and attenuating ESCRT-mediated late endosomal EGFR sorting.

Anti-tumor effects of deubiquitinating enzyme inhibitor PR-619 in human chondrosarcoma through reduced cell proliferation and endoplasmic reticulum stress-related apoptosis.

Chondrosarcoma, a treatment-resistant cancer with limited therapeutic options, lacks significant advancements in treatment methods. However, PR-619, a novel inhibitor of deubiquitinating enzymes, has demonstrated anti-tumor effects in various malignancies. This study aimed to investigate the impact of PR-619 on chondrosarcoma both in vitro and in vivo. Two human chondrosarcoma cell lines, SW11353 and JJ012, were utilized. Cell viability was assessed using an MTT assay, while flow cytometry enabled the detection of apoptosis and cell cycle progression. Western blotting analyses were conducted to evaluate apoptosis, cell stress, and endoplasmic reticulum (ER) stress. Furthermore, the in vivo anti-tumor effects of PR-619 were examined using a xenograft mouse model. The results revealed that PR-619 induced cytotoxicity, apoptosis, and cell cycle arrest at the G0/G1 stage by activating caspases, PARP cleavage, and p21. Moreover, PR-619 increased the accumulation of polyubiquitinated proteins and ER stress by activating IRE1, GRP78, caspase-4, CHOP, and other cellular stress responses, including JNK activation. In vivo analysis demonstrated that PR-619 effectively inhibited tumor growth with minimal toxicity in the xenograft mouse model. These findings provide evidence of the anti-tumor effects and induction of cellular and ER stress by PR-619 in human chondrosarcoma, suggesting its potential as a novel therapeutic strategy for in human chondrosarcoma.

Structure-Imposed Electronic Topology in Cove-Edged Graphene Nanoribbons.

In cove-edged zigzag graphene nanoribbons (ZGNR-Cs), one terminal CH group per length unit is removed on each zigzag edge, forming a regular pattern of coves that controls their electronic structure. Based on three structural parameters that unambiguously characterize the atomistic structure of ZGNR-Cs, we present a scheme that classifies their electronic state (i.e., if they are metallic, topological insulators, or trivial semiconductors) for all possible widths N, unit lengths a, and cove position offsets at both edges b, thus showing the direct structure-electronic structure relation. We further present an empirical formula to estimate the band gap of the semiconducting ribbons from N, a, and b. Finally, we identify all geometrically possible ribbon terminations and provide rules to construct ZGNR-Cs with a well-defined electronic structure.

Topological two-dimensional polymers.

There are more than 200 two-dimensional (2D) networks with different topologies. The structural topology of a 2D network defines its electronic structure. Including the electronic topological properties, it gives rise to Dirac cones, topological flat bands and topological insulators. In this Tutorial Review, we show how electronic properties of 2D networks can be calculated by means of a tight-binding approach, and how these properties change when 2nd-neighbour interactions and spin-orbit coupling are included. We explain how to determine whether or not the resulting electronic features have topological signatures by calculation of Chern numbers, Z2 invariants, and by the nanoribbon approach. This tutorial gives suggestions how such topological properties could be realized in explicit atomistic chemical 2D systems made of molecular frameworks, in particular in 2D polymers, where the edges and vertices of a given 2D net are substituted by properly selected molecular building blocks and stitched together in such a way that long-range π-conjugation is retained.

The synthesis and magnetic properties of a linear mixed-valence [Ni3]5+ in an anthyridine tri-nickel complex.

A novel trinuclear complex [Ni3(µ3-dbay)4Cl2]I3 (1) with a mixed-valence state was prepared by reacting the tridentate ligand 1,13,14-triaza-dibenz[a,j]anthracene (dibenzanthyridine = dbay) with anhydrous NiCl2 and sodium tetraphenylborate. The title compound provides the first example of a trinuclear nickel-anthyridine-based string complex in which the metal framework of complex 1 consists of NiII-NiI-NiII. X-ray crystallography, magnetic susceptibility and detailed EPR measurements were performed to characterize the structure and magnetic properties of this unique complex.

Nonhelical heterometallic [Mo2M(npo)4(NCS)2] string complexes (M = Fe, Co, Ni) with high single-molecule conductance.

Using the planar 1,8-naphthyridin-2(1H)-one (Hnpo) ligand, novel nonhelical HMSCs [Mo2M(npo)4(NCS)2] (M = Fe, Co, Ni) were synthesised and they exhibited high single-molecule conductance.

A heteropentanuclear metal string complex [Mo2NiMo2(tpda)4(NCS)2] with two linearly aligned quadruply bonded Mo2 units connected by a Ni ion and a meso configuration of the complex.

A dimeric molybdenum precursor and nickel ions are used to synthesize a symmetric heteropentanuclear complex, [Mo2NiMo2(tpda)4(NCS)2]. This complex possesses unique structural features, as the four ligands are coordinated to the metal framework in a meso configuration. Furthermore, the central Ni2+ ion is in a high spin state.