Chinese Journal of Chemistry最新文献

A catalyst-free and additive-free ring-opening reaction of polyfluoroalkyl peroxides, triethylenediamine (DABCO), and 1,2-dichloroethane (DCE) has been developed for the defluorinative synthesis of structurally diverse piperazines featuring a fluoroenone framework and a N-chloroethyl-substituent with high Z-stereoselectivity. The success of this three-component reaction is attributed to the in situ generation of an active 1-(2-chloroethyl)-1,4-diazabicyclo[2.2.2]octan-1-ium (DABCO·DCE) salt, which judiciously acts as a formal N-(2-chloroethyl)piperazine equivalent in the defluorinative coupling with less-studied aliphatic fluorinated substances. Impressively, this reaction accomplishes multi-activation of robust C(sp³)-F, C(sp³)-Cl, C(sp³)-O, and C(sp³)-N bonds in a one-pot process, offering a practical platform for the late-stage functionalization of complex molecules. Furthermore, the resulting products can not only serve as versatile building blocks for the synthesis of fluorinated heterocycles, but also undergo C—Cl bond displacement transformations with N-, O-, and S-nucleophiles.

As one of the famous traditional Chinese herbal medicines, Fritillariae Cirrhosae Bulbus (FCB) is widely used in the prevention and treatment of respiratory diseases and has the best curative effect among the known fritillarias medicines. Due to the variety, complex sources, similar appearance and shape, it is difficult to distinguish FCB with high curative effect (h-FCB) from other common fritillarias (c-FCB) in the market. In this paper, a very simple chemiresistor is used to identify FCB from three commonly used fritillarias drugs. The sensors are fabricated by anisotropic electrically conductive metal-organic framework (cMOF) thin film Cu₃(HHTP)₂ (Cu-HHTP_[001] and Cu-HHTP_[100]) as active materials owing to their ability to detect specific groups of volatile organic compounds (volatolomics) as the functional motifs of chemiresistor. As a result, the sensors show orientation-dependence identification ability to FCB. Cu-HHTP_[001]- based sensor shows the highest response (344.17%) to 0.5 g h-FCB powder volatiles among its three other c-FCB which is much higher than Cu-HHTP_[100] (135.50%). Ultimately, Cu-HHTP_[001] can realize the identification of FCB with an accuracy of 97.2% in a simple and real-time manner.

A copper-catalyzed cyanation/diarylmethylation of formamides has been developed for the synthesis of α-cyano functionalized tetra-substituted olefins by utilizing para-quinone methides (p-QMs) and trimethylcyanosilane as functionalization sources. Various kinds of p-QMs and formamides are well tolerated, delivering the desired products with 72%—94% yields, demonstrating broad functional group tolerance. Notably, the reaction does not require noble metals and proceeds regioselectively under mild conditions. Based on step-by-step control experiments, Hammett studies and DFT calculation, a plausible mechanism is proposed.

Arylidenecyclopropanes (ACPs) are highly strained substrates that can be readily utilized for diverse transformations. This study showcases the outcomes of copper-catalyzed ring-opening hydrosilylation and hydroboration reactions of ACPs, showcasing precise cleavage of C—C bonds. The reaction presents an effective and convenient method for producing homoallylic silanes and boronates.

Single-atom catalysts (SACs) have attracted significant attention due to their high atomic utilization and tunable coordination environment. However, the catalytic mechanisms related to the active center and coordination environment remain unclear. In this study, we systematically investigated the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalytic activities of NiN₄, NiN₃, NiN₃H₂, NiN₄X, NiN₃X, and NiN₃H₂X (X denotes axial ligand) through density functional theory (DFT) calculations. This study unveils two distinct reaction pathways for ORR and OER, involving proton-electron pairs adsorbed from both the solution and the catalyst surface. The overpotential is the key parameter to evaluate the catalytic performance when proton-electron pairs are adsorbed from the solution. NiN₃ and NiN₃H₂ show promise as pH-universal bifunctional electrocatalysts for both ORR and OER. On the other hand, when proton-electron pairs are adsorbed from the catalyst surface, the reaction energy barrier becomes the crucial metric for assessing catalytic activity. Our investigation reveals that NiN₃H₂ consistently exhibits optimal ORR activity across a wide pH range, regardless of the source of proton-electron pair (solvent or catalyst surface).

A variety of 3-nitroindazoles and 3-aminoindazoles were prepared in good to excellent yields with high regioselectivity through TBN-mediated nitration at the C3-position of indazoles under the air conditions and sequential reduction. Mechanistic studies revealed that TBN played crucial roles to produce •NO₂ radical source in the presence of air conditions and C3-nitration of indazoles was initiated by N1-nitration and sequential migration of NO₂ group to C3-position. Moreover, this method could be easily applied in the gram scalable synthesis of ibuprofen and ciprofibrate-derived 3-aminoindazoles. The present method highlights air as mild oxidant, metal-free radical nitration of indazole, N—N bond formation and cleavage, and late-stage modification of drugs.

Alkenylsulfonates are commonly encountered in medicinal chemistry, polymer chemistry, and organic synthesis. In this research, an electrochemical reaction involving alkynes, NaHSO₃, and alcohols has been developed. This method yields functionalized alkenylsulfonates in good yields with broad functional group tolerance. Mechanism studies indicate that anodic oxidation of inorganic sulfite, radical insertion process, and HAT process are involved in this transformation.

Layer-by-layer (LbL) solution processing is an efficient method to realize high performance organic solar cells (OSCs). One of the drawbacks of the LbL-processed active layer is the large difference in the crystallinity of the donor and acceptor, which will lead to imbalance charge transfer and result in unfavorable charge recombination. Herein, we combined a novel volatile additive 3,5-dichloro-2,4,6- trifluorobenzotrifluoride (DTBF) with the LbL method to realize high-efficiency OSCs. DTBF interacts with the non-fullerene acceptor BTP-4F by non-covalent bonding, which enhances the crystallinity and compact stacking of BTP-4F. DTBF doped OSC has balanced and efficient electron transport properties, longer carrier lifetime, higher exciton dissociation and charge collection efficiencies, lower energetic disorder than the control OSC without any additives. Benefiting from the optimization of charge dynamics and micro-morphology by DTBF, the binary LbL-processed OSC achieved synergistic improvements in open-circuit voltage, short-circuit current density and fill factor. As a result, a champion power conversion efficiency (PCE) of 19% is realized for DTBF-optimized OSC, which is superior to the control OSC (17.55%). This work demonstrates a promising approach to modulate active layer morphology and fabricate high performance OSCs.