Chinese Journal of Chemistry最新文献

A visible-light-induced decarboxylative radical cascade cyclization reaction between N-(2-cyanoaryl)-acrylamides and alkyl N-(acyloxy)phthalimide (NHPI esters) for the construction of phenanthridine derivatives has been developed. This approach utilizes lithium iodide (LiI) and triphenylphosphine (PPh₃) as the redox catalysts and the alkyl radical is produced through the photoactivation of the electron donor-acceptor (EDA) complex. A series of primary, secondary, and tertiary alkyl-substituted phenanthridines are prepared in up to 82% yield without transition-metal catalysts, chemical oxidants, or metal-/organic dye-based photocatalysts.

An amide-substituted quinuclidine-borane has been identified as a more efficient hydridic hydrogen atom transfer (HAT) catalyst for the hydroalkylation of unactivated olefins under visible-light irradiation. ¹H NMR titration experiments reveal that the amide moiety of the quinuclidine-borane catalyst forms stronger hydrogen bonds with the carbonyl substrates, thereby improving the reaction yields. Furthermore, it was found that the reaction yields correlate well with the association constant between the quinuclidine-borane catalyst and the carbonyl substrate. A scale-up reaction using a continuous-flow photoreactor has also been demonstrated.

Regulating brain iron metabolism and reducing neuronal ferroptosis is proven to be a potential method for treating Alzheimer's disease (AD). However, gastric juice has a pH of 1.1—2.2 where a large number of interfering ions are dissociated from the food, which in turn causes traditional oral iron chelators to be saturated and inactivated. Herein, poly(4-vinylbenzoic acid) polymer chains were introduced as guided by Fe³⁺ ion template into the porous network (TpPa-1) via molecularly imprinted technology to obtain porous iron chelators, COOH@TpPa-1. The COOH@TpPa-1 maintains a multiple hydrogen bonding structure to block the channels in the stomach (pH ~1.1—2.2) with a strongly acidic environment, so just a small amount of active sites have been occupied. As COOH@TpPa-1 enters the colon, the alkaline environment disrupts the original hydrogen-bonded structure and forms anionic fragments, the bonding affinity for Fe³⁺ ions was ~4.0 times that in the stomach, and also gave a high selective coefficient 4.2 times higher than that of conventional iron chelators. These designable "on" and "off" states promote the effective enrichment of iron ions within the colon by the porous chelator and produce a favorable therapeutic effect on Alzheimer's symptoms caused by ferroptosis in mice.

With the rapid development of solid-state batteries, solid-state polymer electrolytes (SPEs) have attracted widespread attention due to their excellent environmental friendliness, designability, and forming film ability. However, due to the limited conductive path of polymers, lithium-ion diffusion kinetics are limited, and low ion conductivity is a huge challenge for SPEs in practical applications. This work provides a polyethylene oxide (PEO) based polymer electrolyte, which has multiple paths of ion diffusion caused by organic polymer framework of poly(hexaazatrinaphthalene) (PHATN). The unique porous channel, the specific surface characteristics, the coordination of -C=N- groups in PHATN with Li⁺, combined with the mobility of PEO segments, make the SPEs have a good ability to conduct Li⁺. Interestingly, the PHATN-PEO/lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) composite electrolytes exhibit excellent electrochemical properties. At room temperature, the conductivity of PHATN-PEO electrolyte can reach 1.03 × 10^–4 S·cm^–1, which is greatly improved compared with 3.9 × 10^–6 S·cm^–1 of PEO. Delightedly, the lithium-ion transference number of PHATN-PEO electrolyte achieves 0.61, and the electrochemical window increases to 4.82 V. The LFP/1%PH-PEO/Li solid-state batteries show good electrochemical cycles. This work reveals an efficient stratagem for the design of polymer solid-state electrolytes.

A new fluorescent fingerprint powder (DFF-MMT) was formulated by blending cyclic chalcone dye DFF with montmorillonite (MMT), which can develop latent fingerprints (LFPs) with exceptional resolution and contrast on various surfaces, including ordinary glass, tin foil, marble, LED screens, and materials with distinct colors and fluorescent backgrounds. The fluorescence of DFF-MMT transforms from orange to bright yellow with LFPs, allowing for a flawless visualization of fingerprints on uneven surfaces or materials with static electricity. Impressively, fingerprints developed by DFF-MMT can be stored for over 21 months and conveniently duplicated. The developed LFPs by DFF-MMT still keep high quality under the influence of aquatic condition, illumination and thermal effects. DFF-MMT also exhibits benefits, such as affordability, real-time, high-resolution, high-contrast development and no damage to DNA, making it an ideal choice for sophisticated criminal investigations.

To address the stereoselective synthesis challenge in π-stacked grids with four chiral centers, we utilized coplanar and highly rigid 11,12-dihydroindeno[2,1-a]fluorene-11,12-diol and 2,2'-bithiophene as synthons, employing Friedel-Crafts gridization (FCG). Leveraging the supramolecular interactions of S···S and π···π within the thiophene moiety, along with the steric effect of the 11,12-dihydroindeno[2,1-a]fluorene scaffold, we successfully achieved the exclusive generation of a single isomer of Ladder-type π-stacked grids (LGs-IF) containing six theoretical isomers. By subsequently substituting 2,2'-bithiophene with thiophene/bithiophene derivatives as synthons, we maintained an exceptionally high level of stereoselectivity. This study introduces a novel approach for the stereo-controlled preparation of grids involving multi-chiral centers.

Herein, an unprecedented nickel-catalyzed regioselective hydroalkynylation of unsymmetrical internal alkynes was realized with steric hindered resistance selectivity via the cyano-directing group strategy. Significantly, the resulting 1,3-enyne products could be effectively employed in the synthesis of novel nitrogen-containing tricyclics compounds, that provided the potential candidate compound 8a (IC₅₀ = 2.6—6.1 μmol/L) for the anti-tumor cell proliferation activity. Therefore, this work not only improves the transition-metal- catalyzed hydroalkynylation strategy of internal alkynes, but also exhibits versatility of 1,3-enynes in the construction of the complex bioactive chemical space.

Photocatalysis is a promising green approach for water purification. The diversity of water pH values is a key factor that restricts its practical application since pH affects the adsorption of organic molecules, the stability of catalysts and photocatalytic performance. Here, we report a pH–independent, efficient and stable photocatalytic system with a liquid (water)–liquid (oil)–solid (semiconductor) (L–L–S) triphase interface microenvironment. The system is fabricated by coating a thin layer of silicon oil on the surface of ZnO nanowire arrays, a model chemically unstable semiconductor in both acidic and alkaline solutions. We show that the unique interface makes the dye adsorption pH independent and prevents the semiconductor from being corroded by strong acidic/alkaline solutions, leading to a stable and efficient photocatalytic reaction over a wide pH range (1—14). These findings reveal a promising path for the development of high-performance catalysis systems applicable in complex water environments.

pH is an important stimuli-responsive signal because deprotonation-protonation process is crucial for many life functions. Photoacid is a kind of photoresponsive group that can release protons upon irradiation. This property makes invasive pH control can be replaced by noninvasive light control. However, photoacid is rare. In this work, macrocyclic calixpyridinium was found to be used as a photoacid to release protons from acidic methylene under the irradiation of a 254 nm UV lamp. When the solution of calixpyridinium−disulfonated xantphos aggregates were irradiated by a 254 nm portable UV lamp, disulfonated xantphos was able to receive the protons released from calixpyridinium. This noninvasive photocontrolled proton transfer not only replaces an invasive pH regulation but also achieves a synergistic function. The deprotonation of calixpyridinium and the protonation of disulfonated xantphos can occur simultaneously to disrupt the aggregates. Moreover, the photoresponsive disassembly is reversible by heating. This photoresponsive material was further applied as a photocontrolled release model. In addition, a dissipative assembly was successfully designed based on this photoresponsive disassembly. This study supplies a generalized strategy to construct pH-responsive biocompatible materials with light-control properties by using macrocyclic calixpyridinium and its matched various guests in water.