In recent years, visible-light-mediated C–H bond functionalization has become an emerging field at the forefront of organic synthesis. It is of considerable interest to academic and industrial ...chemists owing to the atom/step economical features as well as the overall sustainability. In this Letter, we mainly discussed the recent typical examples in sp2 and sp3 C–H bond functionalization by means of visible-light photoredox catalysis.
A facile, site‐selective, and divergent approach to construct 2‐aminopyrroles and quinoline‐fused polyazaheterocycles enabled by a simple gold(III) catalyst from ynamides and anthranils under mild ...reaction conditions is described. This one‐pot strategy uses readily available starting materials, proceeds in a highly step‐ and atom‐economical manner, with broad substrate scope and scale‐up potential. The key element for success in this tandem reaction is a catalyst‐directed preferred quenching of the in situ generated gold carbene intermediates by a nucleophilic benzyl/2‐furylmethyl moiety on the ynamides as an alternative to the known C−H annulation leading to indoles.
One‐pot strategy: A simple gold(III) catalyst enables the construction of 2‐aminopyrroles and quinoline‐fused polyazaheterocycles from ynamides and anthranils under mild reaction conditions. This strategy uses readily available starting materials, proceeds in a highly step‐ and atom‐economical manner, with broad substrate scope and scale‐up potential.
Pt(II) and Au(III)-mediated intermolecular divergent annulations of benzofurazans and ynamides highlighted the N- to O-selectivity of tunable metal carbene intermediates. PtCl
with a bulky phosphite ...ligand resulted in the specific synthesis of six-membered quinoxaline N-oxides and successfully suppressed the in-situ deoxygenation of N-oxides. On the other hand, an unique gold(III) catalyst (2,6-di-MeO-PyrAuCl
) led to the five-membered ring products, benzimidazoles. A broad scope of functional groups was well compatible, delivering better yields and selectivities in contrast to conventional gold(I) catalysts. The different behavior of presumed platinum(II) and gold(III) carbenes with respect to chemoselectivity was intensively examined by experiments and DFT calculations. A detailed mechanistic study, based on DFT calculations, revealed that the highly electrophilic carbocation-like gold(III) carbene triggers an oxophilic cyclization, followed by a cascade ring contraction and acyl migration. On the contrary, the Pt carbene species is less cationic, favoring the formation of the six-membered ring via N-attack.
A novel and highly efficient gold(III)-complex catalyzed aerobic oxidative α-C-H functionalization of amines has been developed. The tertiary amines can be directly coupled with various nucleophiles ...using air as a sustainable oxidant.
A copper-mediated C2-cyanation of indoles using cheap and commercially available acetonitrile as the “nonmetallic” cyanide source was achieved through sequential C–C and C–H bond cleavages. The ...installation of a removable pyrimidyl group on the indole nitrogen atom is the key for this C2 selectivity. This approach provides a novel and alternative route leading to indole-2-carbonitrile.
Early‐stage lung cancer is now more commonly identified in the form of ground‐glass nodules (GGNs). Presently, the treatment of lung cancer with GGNs mainly depends on surgery; however, issues still ...exist such as overtreatment and delayed treatment due to the nonuniform standard of follow‐up. Therefore, the discovery of a noninvasive treatment could expand the treatment repertoire of ground‐glass nodular lung cancer and benefit the prognosis of patients. Immunotherapy has recently emerged as a new promising approach in the field of lung cancer treatment. Thus, this study presents a comprehensive review of the immune microenvironment of lung cancer with GGNs and describes the functions and characteristics of various immune cells involved, aiming to provide guidance for the clinical identification of novel immunotherapeutic targets.
Immunotherapy is occupying an increasingly crucial position in the treatment of lung cancer. However, the immunotherapeutic approaches for ground‐glass nodules are still not fully developed, which implies that conducting research on the immune microenvironment is definitely a way to seek effective immunotherapy. In this study, we reviewed the differences in the abundance and functionality of various immune cells among normal lung tissue, ground‐glass nodule lung adenocarcinoma and solid nodule lung adenocarcinoma, and further discussed the complex tumor immune microenvironment formed by various immune cells through intercellular contact or cytokine secretion, with the aim of uncovering potential immunotherapeutic targets for ground‐glass nodule lung adenocarcinoma.
The poor performance of LiNi
0.5
Co
0.2
Mn
0.3
O
2
cathode materials in lithium-ion batteries under high cut-off voltage, such as fast capacity fading and poor cycle capability, hinders the ...development of high energy density lithium-ion batteries. Surface modification is generally conducted on the electrode to improve high cut-off voltage performance. In this study, Al
2
O
3
and graphene are co-coated on the surface of LiNi
0.5
Co
0.2
Mn
0.3
O
2
. The Al
2
O
3
/graphene co-coating layer effectively reduces side reactions and HF erosion and facilitates lithium-ion diffusion/electronic conduction. The degree of cation mixing and electrode polarization is also decreased by the co-coating from the XRD and cyclic voltammetry results. The modified sample exhibits improved electrochemical properties under high cut-off voltage (3–4.5 V): The initial discharge capacity and coulombic efficiency of the modified sample reaches 187.2 mAh g
−1
and 87.0%, which is higher than the pristine NCM (161.0 mAh g
−1
, 82.9%). The co-coating electrode possesses a high cycling retention of 88.2% with 10% improvement at a current density of 180 mA·g
−1
(1 C) after 200 cycles, and the rate capability reaches 119.6 mAh·g
−1
at 1800 mA·g
−1
(10 C), compared to 78.6 mAh·g
−1
of the pristine sample. The modification effect in different voltage ranges (3–4.5 V and 3–4.3 V) was compared, which shows a more significant improved effect under high voltage than low voltage: The cycle retention after 200 cycles is increased by 10% at 3–4.5 V, higher than 7.7% (3–4.3 V), which is due to the intensified side reactions under high voltage being suppressed by co-coating.
The electrochemical performances of LiNi0.5Co0.2Mn0.3O2 (NCM523) layered cathode material, such as poor rate capacity and cycling stability caused by undesirable intrinsic conductivity and low rate ...of lithium ion transportation, are not fairly good especially at elevated rate and cut-off voltage. To improve these properties, in this study, the co-coating layer of graphene and TiO2 was constructed on NCM523 surface. The graphene/TiO2 coating layer could effectively prevent hydrofluoric acid (HF) attacks, suppress the side reaction, accelerate the lithium ion diffusion and facilitate the electron migration. The enhancement of cycle performance and rate capacity was contributed to the uniform co-modified surface, interacting each other and thus exhibiting synergistic effects.
A co-coating layer of graphene/TiO2 is constructed on LiNi0.5Co0.2Mn0.3O2 surface, which could effectively prevent hydrofluoric acid (HF) attacks, suppress the side reaction, accelerate the lithium ion diffusion and facilitate the electron migration. Display omitted
1.A graphene/TiO2 coating layer is coated on LiNi0.5Co0.2Mn0.3O2 surface.2.The graphene/TiO2 coating layer much improves the rate capability and cycling stability, decreases the charge transfer resistance and electrochemistry polarization.3.The graphene/TiO2 coating layer could effectively prevent hydrofluoric acid (HF) attacks, suppress the side reaction, accelerate the lithium ion diffusion and facilitate the electron migration.
LiNi
0.6
Co
0.2
Mn
0.2
O
2
(NCM622) is a kind of high nickel ternary cathode materials for lithium-ion batteries with high energy density and high discharge platform. However, the insufficient ...electron/ion conductivities and corrosion of hydrofluoric acid have limited its practical usage. In overcoming the challenges, it is particularly important to find a method that can improve both electronic and ionic conductivities of such a material. In this study, aluminum (Al)-doped polypyrrole (Al@PPy) is used to coat NCM to improve its rate and cycling performance. Compared with the uncoated NCM, Al@PPy-NCM has more electron/ion transport channels and much better cycling stability. It has an initial capacity of 224.3 mAh/g at a current density of 20 mA/g, and a capacity retention rate of 91.6% after 100 cycles in voltage range of 3.0–4.5 V. At a current density of 200 mA/g, the initial capacity can still be 185.1 mAh/g, and the capacity retention rate can maintain at 88.1% after 200 cycles.
Layered LiNi
0.6
Co
0.2
Mn
0.2
O
2
as a promising cathode material for lithium-ion batteries possesses high theoretical capacity and broad application prospects. However, the destruction of structure ...during the cycles and the insufficient conductivity severely restrict the cycle life and rate capacity, especially at high cut-off voltage. As an improvement, the dual-coating of LiAlO
2
and graphene oxide (GO) was designed to modify the microstructure and migration dynamics of NCM622 surface. Compared to single coating, LiAlO
2
/GO showed a synergistic effect that simultaneously increased ion/electron transfer rate, reversibility and cycling stability of the cathode material. As a result, the initial capacity of the dual-coating material was 182.6 mAh/g at 200 mA/g (1 C) with a capacity attenuation of 0.06% per cycle in 200 cycles, while it was 222.6 mAh/g at 20 mA/g (0.1 C), and the rate capacity was 100.4 mAh/g at 2000 mA/g (10 C) in a voltage range of 3.0–4.5 V.
