Ionic liquid post-modified carboxylate-rich MOFs for efficient catalytic CO2 cycloaddition under solvent-free conditions.

The synthesis of cyclic carbonates through cycloaddition reactions between epoxides and carbon dioxide (CO2) is an important industrial process. Metal-Organic Frameworks (MOFs) have functional and ordered pore structures, making them attractive catalysts for converting gas molecules into valuable products. One approach to enhance the catalytic activity of MOFs in CO2 cycloaddition reactions is to create open metal sites within MOFs. In this study, the amino-functionalized rare earth Gd-MOF (Gd-TPTC-NH2) and its ionic liquid composite catalysts (Gd-TPTC-NH-[BMIM]Br) were synthesized using 2'-amino-[1,1':4',1''-terphenyl]-3,3'',5,5''-tetracarboxylic acid (H4TPTC-NH2) as the ligand. The catalytic performance of these two catalysts was observed in the cycloaddition reaction of CO2 and epoxides. Under the optimized reaction conditions, Gd-TPTC-NH-[BMIM]Br can effectively catalyze the cycloaddition reaction of a variety of epoxide substrates with good to excellent yields of cyclic carbonate products. Comparatively, epichlorohydrin and epibromohydrin, which possess halogen substituents, promote higher yields of cyclic carbonates due to the electron-withdrawing nature of Cl and Br substituents. Additionally, the Gd-TPTC-NH-[BMIM]Br catalyst demonstrated good recyclability and reproducibility, maintaining its catalytic activity without any changes in its structure or properties after five reuse cycles.

A New 1,3-Benzodioxole Compound from Hypecoum erectum and Its Antioxidant Activity.

The purpose of this study was to identify the chemical components in aerial parts of Hypecoum erectum. A new 1,3-benzodioxole derivative, identified as Hypecoumic acid (1), was isolated, together with the three known compounds: protopine (2), coptisine (3), and cryptopine (4). Their structures were identified based on extensive spectroscopic experiments, including nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectra (HR-ESI-MS), as well as comparison with those reported in the literature. Meanwhile, the in vitro antioxidative activity of all compounds was determined using a DPPH-scavenging assay, and compound 1 (IC50 = 86.3 ± 0.2 µM) was shown to have moderate antioxidative activity.

Femtosecond Pulsed Fiber Laser Based on Graphdiyne-Modified Tapered Fiber.

We report the application of saturable absorbers prepared from graphdiyne-modified tapered fibers to an erbium-doped fiber laser to achieve a femtosecond pulse output. Graphdiyne quantum dots are successfully prepared by the Glaser-Hay method. The graphdiyne-based all-fiber saturable absorber device exhibited strongly saturable absorption characteristics with a modulation depth of 18.06% and a saturation intensity of 103.5 W. The net dispersion of the erbium-doped fiber laser cavity is ~0.016 ps2, and a femtosecond pulse output with a bandwidth of 26.3 nm, a pulse width of 135.8 fs, and a single pulse capability of 54 pJ is obtained. This work lays the foundation for the application of the nonlinear optical material, graphdiyne, in ultrafast photonics.

Efficient adsorption of methyl orange and methyl blue dyes by a novel triptycene-based hyper-crosslinked porous polymer.

It is still a great challenge to develop new materials for the highly efficient entrapment of organic dyes from aqueous solution. Herein, a novel triptycene-based hyper-crosslinked porous polymer (TPP-PP) was designed and synthesized by a simple Friedel-Crafts reaction. The obtained polymer TPP-PP has a high surface area, abundant pore structure and stable thermal performance. Due to the above characteristics, TPP-PP has good adsorption performance for anionic methyl orange solution (MO) and cationic methyl blue solution (MB). Under the optimal experiment conditions, the TPP-PP showed an excellent adsorption capacity for MO (220.82 mg g-1) and MB (159.80 mg g-1), respectively. The adsorption kinetics fitted the pseudo-second-order model. The adsorption of MO by TPP-PP reaches equilibrium within 180 minutes, and the adsorption of MB reaches equilibrium within 150 minutes. The adsorption behavior was not only spontaneous but also endothermic in reality. At the same time, TPP-PP also has good reusability. After 5 cycles of experiments, the removal rate of MO and MB by TPP-PP can still reach more than 80%. Thus, the Friedel-Crafts reaction crosslinked method might be a promising approach for the synthesis of novel material for the highly efficient extraction of dye wastewater.

Graphdiyne-deposited microfiber structure all-optical modulator at the telecommunication band.

All-optical modulator is a crucial device in next generation of all-optical communications, interconnects, and signal processing. Here, we demonstrate an all-optical phase modulator with graphdiyne (GDY)-deposited microfiber structure. The phase shift of the signal light can be readily controlled by pump light by thermo-optic effect. This all-optical modulator can achieve a phase shift slope of 0.0296 π·mW-1 and a rising time of 5.48 ms at 25 Hz (3 ms, 50 Hz). Modes distributions in GDY-deposited microfiber at different wavelength are numerical analyzed and the normalized phase conversion efficiency of GDY are calculated. The results show that GDY has a considerable normalized phase conversion efficiency of 0.1644 π·mW-1·mm-1, which is higher than that of graphene, MXene and WS2 based all-optical modulators. This work proves the potential of GDY in all-optical modulator device at telecommunication band and provides a support to all-optical signal processing systems.

A Regioselectively Oxidized 2D Bi/BiOx Lateral Nano-Heterostructure for Hypoxic Photodynamic Therapy.

Optoelectronic science and 2D nanomaterial technologies are currently at the forefront of multidisciplinary research and have numerous applications in electronics and photonics. The unique energy and optically induced interfacial electron transfer in these nanomaterials, enabled by their relative band alignment characteristics, can provide important therapeutic modalities for healthcare. Given that nano-heterostructures can facilitate photoinduced electron-hole separation and enhance generation of reactive oxygen species (ROS), 2D nano-heterostructure-based photosensitizers can provide a major advancement in photodynamic therapy (PDT), to overcome the current limitations in hypoxic tumor microenvironments. Herein, a bismuthene/bismuth oxide (Bi/BiOx)-based lateral nano-heterostructure synthesized using a regioselective oxidation process is introduced, which, upon irradiation at 660 nm, effectively generates 1 O2 under normoxia but produces cytotoxic •OH and H2 under hypoxia, which synergistically enhances PDT. Furthermore, this Bi/BiOx nano-heterostructure is biocompatible and biodegradable, and, with the surface molecular engineering used here, it improves tumor tissue penetration and increases cellular uptake during in vitro and in vivo experiments, yielding excellent oxygen-independent tumor ablation with 660 nm irradiation, when compared with traditional PDT agents.

Hetero-MXenes: Theory, Synthesis, and Emerging Applications.

Since their discovery in 2011, MXenes (abbreviation for transition metal carbides, nitrides, and carbonitrides) have emerged as a rising star in the family of 2D materials owing to their unique properties. Although the primary research interest is still focused on pristine MXenes and their composites, much attention has in recent years been paid also to MXenes with diverse compositions. To this end, this work offers a comprehensive overview of the progress on compositional engineering of MXenes in terms of doping and substituting from theoretical predictions to experimental investigations. Synthesis and properties are briefly introduced for pristine MXenes and then reviewed for hetero-MXenes. Theoretical calculations regarding the doping/substituting at M, X, and T sites in MXenes and the role of vacancies are summarized. After discussing the synthesis of hetero-MXenes with metal/nonmetal (N, S, P) elements by in situ and ex situ strategies, the focus turns to their emerging applications in various fields such as energy storage, electrocatalysts, and sensors. Finally, challenges and prospects of hetero-MXenes are addressed. It is anticipated that this review will be beneficial to bridge the gap between predictions and experiments as well as to guide the future design of hetero-MXenes with high performance.

An Easy Method of Synthesis CoxOy@C Composite with Enhanced Microwave Absorption Performance.

Design of interface-controllable magnetic composite towards the wideband microwave absorber is greatly significance, however, it still remains challenging. Herein, we designed a spherical-like hybrids, using the Co3O4 and amorphous carbon as the core and shell, respectively. Then, the existed Co3O4 core could be totally reduced by the carbon shell, thus in CoxOy core (composed by Co and Co3O4). Of particular note, the ratios of Co and Co3O4 can be linearly tuned, suggesting the controlled interfaces, which greatly influences the interface loss behavior and electromagnetic absorption performance. The results revealed that the minimum reflection loss value (RLmin) of -39.4 dB could be achieved for the optimal CoxOy@C sample under a thin thickness of 1.4 mm. More importantly, the frequency region with RL < -10 dB was estimated to be 4.3 GHz, ranging from 13.7 to 18.0 GHz. The superior wideband microwave absorption performance was primarily attributed to the multiple interfacial polarization and matched impedance matching ability.

Development of sulfide, nitrogen co-doping hollow carbon with wideband electromagnetic absorption capability.

Exploration of an economic, easy-producing method to develop high-performance electromagnetic absorber has been a global research interest, owing to the increasingly electromagnetic pollution and interference. In this work, sulfide, nitrogen co-doping carbon (NS-HCS) has been successfully prepared by an in situ copolymer and subsequent calcination reaction. The morphologies and phase compositions of these as-prepared samples are analyzed via the transmission electron microscopy (TEM), element mappings, X-ray diffraction (XRD) and X-ray photoelectron spectrum (XPS). The result confirms the hollow shaped structure of amorphous carbon is constructed with various types of N, S based covalent bonds. The dotted N and S elements are contribution for the conductive loss and dipole polarization relaxation behavior. The minimum reflection loss value of -34 dB, and effective bandwidth reaches 6.8 GHz with only 1.6 mm. The as-prepared wideband electromagnetic absorber will pave a simple and effective method to obtain lightweight, broadband and thin thickness electromagnetic absorption materials.

Synthesis of the Tricyclic Picrotoxane Motif by an Oxidative Cascade Cyclization.

An oxidative cascade cyclization of ß-keto esters has been developed for the construction of the tricyclic picrotoxane motif in a single step, and DFT calculations suggested a possible cationic cyclization mechanism. This cascade cyclization can be operated on a 20 g scale to obtain a 77% total yield of the tricyclic products, which in turn can be converted to versatile intermediates for further elaboration to picrotoxanes and their structurally related compounds.

In(OTf)3-Catalyzed Cascade Cyclization for Construction of Oxatricyclic Compounds.

A highly diastereoselective cascade cyclization reaction has been developed for establishing a series of oxatricyclic compounds using Chan's diene and simple keto alkynal substrates with only 1 mol % of In(OTf)3 as the catalyst in 82-92% yields. The potential utility of this synthetic strategy has been demonstrated in model studies for the construction the core structures of 1α,8α:4α,5α-diepoxy-4,5-dihydroosmitopsin and cortistatin A.

Formal Synthesis of (+)-Phomactin A.

A concise formal synthesis of (+)-phomactin A has been achieved. The key features of this synthetic strategy involve a one-pot Prins/Conia-ene cyclization protocol for the construction of the highly functionalized 1-oxadeclin core (AB ring) and a late-stage direct γ-hydroxylation of enone for the installation of the C ring.

Tunable Cyclization Strategy for the Synthesis of Zizaene-, allo-Cedrane-, seco-Kaurane-, and seco-Atesane-Type Skeletons.

A versatile Lewis acid-mediated cyclization strategy has been developed for selectively establishing zizaene-, allo-cedrane-, seco-kaurane-, and seco-atesane-type skeletons. The zizaene- and seco-atesane-type skeletons can be obtained in a cascade manner, which involves Diels-Alder reaction of cyclic enones with bis-silyloxy dienes and carbocyclization of yne-enolates through Lewis acid dependent 5- or 6-exo-dig modes. This cyclization strategy was also employed for the core synthesis of tashironin.

Diastereoselective Total Synthesis of (±)-Basiliolide B and (±)-epi-8-Basiliolide B.

The C8 and C9 stereogenic centers of the basiliolide/transtaganolide family have been established stereoselectively using a cyclopropane ring-opening strategy, which has been studied by DFT calculations of a variety of lithium-chelating models. The highly functionalized intermediates obtained in this strategy were successfully employed for the diastereoselective total synthesis of (±)-basiliolide B and (±)-epi-8-basiliolide B. The decalin core with a lactone bridge was constructed via a 2-pyrone Diels-Alder (DA) cycloaddition, and the unprecedented seven-membered acyl ketene acetal was established by a biomimetic intramolecular O-acylation cyclization.

Enantioselective Synthesis of the ABC-Tricyclic Core of Phomactin A by a γ-Hydroxylation Strategy.

An enantioselective synthesis of the ABC-tricyclic furanochroman core of phomactin A has been accomplished by a γ-hydroxylation approach. The C ring was established by γ-hydroxylation of an α-enone. The regioselectivity was optimized by using a strong base with an oxophilic cation (t-BuLi) and a bulky oxygen donor (Davis reagent), which afforded the γ-hydroxylation product selectively in 63% yield.

A biomimetic synthesis of (±)-basiliolide B.

A highly diastereoselective and practical biomimetic total synthesis of (±)-basiliolide B has been achieved through the study of the two proposed biosynthetic pathways (O-methylation and O-acylation) for the unprecedented 7-methoxy-4,5-dihydro-3H-oxepin-2-one (C ring). The synthesis featured a cyclopropanation/ring opening strategy for establishing the stereogenic centers at C8 and C9, a biomimetic 2-pyrone Diels-Alder cycloaddition for the synthesis of the ABD ring system, and finally a highly efficient biomimetic intramolecular O-acylation for the C ring formation. This result provides an important perspective on the biosynthetic origin of the unprecedented 7-membered acyl ketene acetal moiety of the C ring.

catena-Poly[[dichloridozinc(II)]-µ-1,1'-(hexane-1,6-di-yl)diimidazole-κN:N].

In the structure of the polymeric title compound, [ZnCl(2)(C(12)H(18)N(4))](n) or [ZnCl(2)(L)](n), where L = 1,1'-(hexane-1,6-di-yl)diimidazole, the Zn(II) centre is coordinated by two N atoms of two different L ligands and by two chloride anions in a distorted tetra-hedral geometry. The organic ligand links adjacent metals to form a polymeric chain along the c axis. The chains are further connected into layers parallel to the bc plane by inter-molecular C-H⋯Cl hydrogen bonds. Two C atoms of the central hexyl chain are disordered over two positions with site-occupancy factors of 0.5.