Chemistry - An Asian Journal最新文献

The study highlights an innovative approach to developing a highly selective delayed fluorescent probe for the dual-mode detection of a cancer hallmark within the endoplasmic reticulum (ER, depicted as a greenish-blue structure). The ER-specific probe, designed for selective detection of nitroreductase (NTR, shown in orange), is initially in a non-fluorescent state (grey). Upon interacting with NTR, the probe activates, emitting green fluorescence and long-lived emission, enabling intracellular detection through luminescence and time-resolved imaging modes symbolized by clock icons. More details can be found in article number e202401226 by Abhijit Patra and co-workers.

In article number e202401361, Mary Sajini Devadas and co-workers report the synthesis of the novel Pt-doped Au₁₁ nanocluster (PtAu₁₀(PPh₃)₇Br₃). The prototypical halide- and phosphine-ligated Au₁₁ cluster displays no measurable photoluminescence; the addition of the central Pt dopant expands the HOMO-LUMO band gap resulting in photoluminescence from the cluster (Φ = 1.88%). This work highlights rationally guided methods for inducing photoluminescence via band-gap engineering methods.

The slow dynamics of oxygen evolution reaction and the use of the proton exchange membrane have been troubling the hydrogen production from electrolytic water splitting. Reducing the electrolytic voltage and avoiding the utilization of proton exchange membranes are crucial targets for electrolytic hydrogen evolution. Bi-doped NiCo2O4 catalyst is prepared and applied in electrocatalysis glucose oxidation coupled hydrogen generation. Structural characterizations confirm the successful preparation of NiCo2O4 and the existence of Bi. Bi leads to the electrons transfer from Co to Ni, increasing the content of Co3+, and lowers the oxidation potential of Co and Ni. Electrochemical experiments indicate that NiCo2O4-Bi has good electrocatalytic activity and stability toward electrochemical glucose oxidation, with a potential of 1.13 V vs. RHE at 10 mA cm-2 current density. The asymmetric electrolysis of two electrodes requires just 1.26 V to achieve a 10 mA cm-2 current density. The design of NiCo2O4-Bi is an exploration for electrocatalytic glucose oxidation coupled hydrogen production with low voltage and no proton exchange membrane.

Asymmetric conjugated diradicals are much less common than their symmetric counterparts because they expand the feasibility of symmetry, but they also present some detrimental aspects. Hence, stud-ies comparing analogue symmetric and asymmetric diradicals are of interest. Previous studies regard-ing the structure of asymmetric conjugated diradicals only focused on analyzing different radical moie-ties attached to the same π-core bridge, while none of them explored the diradicals with asymmetric π-core (same radical moieties). Herein, we report a series of azine derivatives PNP-n (n=1-3). The symmetric diradicals PNP-1 and PNP-3 have a π-core comprising two benzenes or two thiophene units linked to a central azine, respectively. Replacing a benzene unit with thiophene in symmetric PNP-1 diradical yields the asymmetric PNP-2 diradical altering the energy gap and the spin-spin coupling strengths thus modulating the diradical characteristic. This work highlights the advantages and incon-veniences of moving from symmetric to asymmetric diradicals, as well as providing a molecular de-scription of the intrinsic properties of ones and others made of similar chemical compositions.

Biomass-derived carbon quantum dots (CQDs) are emerging as versatile catalysts, showcasing remarkable potential in diverse applications. This includes catalytic hydrogenation, selective reduction of nitroaromatic compounds, and degradation of azo dyes. Their eco-friendly synthesis, high surface area, and tunable properties make CQDs an ideal choice for sustainable chemical transformations, offering a green pathway for industrial and environmental applications. More details can be found in article number e202401005 by Navneet Kumar Gupta and co-workers.

Transannular carbocation cyclization of the achiral benzannulated cyclononene tertiary alcohols under acid catalysis furnished the [5/6]-fused tetracycles with three contiguous stereogenic centers, one of which is an all-carbon C11b quaternary center, in good to excellent yields and diastereoselectivity. Hydride, water, azide, allyl, and electron-rich (hetero)arenes could be employed as nucleophiles. The reaction is under both substrate- and condition-control. Further functionalization of some selected substrates was also demonstrated. Computational chemistry delineated different competing reaction pathways such as direct substitution at the bisbenzylic position for other related systems-the benzannulated cyclooctene/cyclononene secondary alcohols and provided further evidence for the observed stereoselectivity.

The creation of quaternary carbon centers has been a formidable challenge in organic synthesis due to steric impediments, especially for the polyaryl substituted quaternary carbon centers. Up to now, a few of methods were reported for achieving the α-arylation of 3-aryloxindoles to construct 3,3-diaryloxindoles. We now asserted the TfOH-catalyzed cross-dehydrogenative coupling reaction between the tertiary C(sp3)-H and readily available arenes under air atmosphere in green reaction medium for rapid construction of 3,3-diaryloxindoles. In addition, the mechanism of the metal-free cross-dehydrogenative coupling with air as oxidant was meticulously explored.

Truxenes, the π-conjugated small molecules with a C3h-symmetry, have been extensively investigated in synthesis and application as organic optoelectronic materials. Compared to truxenes, triindenotrithiophene (TITT), a thienyl congener of truxene, was much less explored in the field of synthetic chemistry as well as photovoltaic applications. Different from the reported synthesis requiring at least 14 steps to access TITT-related small molecules, in this work, we have successfully developed a 7-step new synthetic route to TITT and its π-extended oligoaryls (YCW01-04). Our synthetic strategy involved two direct C-H/C-Br coupling reactions, avoiding tedious protection/deprotection chemical transformations. Essential reaction conditions including ligand, base, and solvent for direct C-H arylations were well optimized, thus affording target products in yields up to 87% (YCW02). In addition, for the first time, the TITT core-based oligoaryls were fabricated as hole-transporting material (HTM) in perovskite solar cells (PSC), giving the highest power conversion efficiency (PCE) of 15.3% (YCW01).

Ideal liquid sorbents, such as phenolate zwitterions, represent a novel and promising technology for CO2 capture. To enhance their design and reactivity with CO2, two types of substituents, electron-donating groups (EDGs) and electron-withdrawing groups (EWGs) were investigated. Using Density Functional Theory (DFT) with a large basis set, their effectiveness as reactivity modulators was assessed through energy decomposition analysis, non-covalent interaction, natural bond orbitals (NBO), evaluation of reaction energy barriers and pKa. EDGs, in general, enhance phenolate reactivity and stability, highlighting their potential in the design of advanced zwitterionic sorbents for CO₂ capture. Conversely, EWGs demonstrated mixed effects, providing lower CO2 capture effectiveness but enhancing recyclability of the phenolates. In summary, our findings provide a framework to investigate substituent efficacy and design next-generation carbon capture materials.

Eight indole-boron-difluoride complexes were synthesized from 2,3-arylpyridylindole derivatives via Sonogashira coupling and Larock heteroannulation. These complexes exhibited distinct photophysical properties. Solvent polarity influenced their spectral behavior, showing hypsochromic absorption, bathochromic emission shifts, and aggregation-induced emission (AIE) in mixed solvents. The ¹⁹F NMR shifts and photophysical properties, including excitation, emission maxima, and Stokes shift, correlated with Hammett substituent constants, highlighting electronic effects on molecular properties. The synthesized complexes exhibited a range of intramolecular charge transfer (ICT) behaviors, as evidenced by their Lippert-Mataga parameters. TD-DFT calculations aligned with experimental data, offering insight into spectroscopic behavior. Notably, the indole-boron-difluoride complex, bearing a methyl ester group, exhibited significant anticancer activity against HeLa cells and potential for fluorescence imaging, indicating its promise for biomedical applications in cell imaging and therapy.