Synthesis of a Novel Solid Acid with both Sulfonic and Carbonyl Acid Groups and Its Catalytic Activities in Acetalization

The novel solid acid with both sulfonic and carbonyl acid groups has been synthesized from 3-((2-sulfoethoxy) carbonyl)acrylic acid and tetraethyl orthosilicate(TEOS). The catalytic activities were investigated through the acetalization. The results showed that the novel solid acid was very efficient for the reactions with the high yields. The high acidity, high stability and reusability were the key feature of the novel solid acid. Moreover, the sulfonic and carbonyl acid groups could cooperate during the catalytic process, which improved its catalytic activities. The catalyst shows recyclability, and hold great potential for replacement of homogeneous catalysts.

OXIDATION OF α-METHYL OR α-METHYLENE GROUPS IN CARBONYL COMPOUNDS WITH AMMONIUM CHLOROCHROMATE

This paper reports a new method for oxidizing the α-methyl or α-methylene groups in carbonyl compounds into 1,2-dicarbonyl compounds by ammonium chlorochromate(ACC).

Narrowband blue emitter based on fused nitrogen/carbonyl combination with external quantum efficiency approaching 30%

Multi-resonance thermally activated delayed fluorescence(MR-TADF)emitters can enable narrowband emission with high color purity and electroluminescence efficiency.Nitrogen/carbonyl(N/C=O)system is receiving increasing attention while the nitrogen/boron(N/B)system has been widely studied.Donor decoration is an effective approach for N/B type MR-TADF system but always leads to broadening and red-shifting of the emission band in N/C=O MR-TADF system.We attribute these unfavorable phenomena to the formation of intramolecular charge transfer between the MR-core and peripheral donors.To address this issue,we have developed a new strategy by decorating DMQAO(a fused N/C=O MR-core)with a triazine acceptor and a neutral terphenyl group to construct MTDMQAO and MBDMQAO,respectively.The introduction of the triazine acceptor not only realizes efficient narrowband emission in MTDMQAO,but also accelerates the reverse intersystem crossing process through enhanced spin-orbital coupling.As a result,MTDMQAO exhibits a significantly higher external quantum efficiency of 29.4%compared to the referent emitters,validating the rationality of our derivation strategy.This study highlights the potential of the N/C=O system for MR-TADF emitters and provides important insights for understanding the difference between N/B and N/C=O systems.

Improved crystallinity and self-healing effects in perovskite solar cells via functional incorporation of polyvinylpyrrolidone

Air moisture is the key issue for perovskites which invades the films and accelerates the damage of devices. Here, polyvinylpyrrolidone(PVP) is introduced to the methylammonium lead iodide(MAPbI_(3)) perovskite precursor to control crystal growth and endow the devices with self-healing ability in a moisture environment. The strong C=O...ΗAΝ hydrogen bonding interactions between PVP and MAPbI_(3) was confirmed by nuclear magnetic resonance measurements. By introducing hydrogen bonding in the MAPbI_(3)-based PSCs, we form a compact perovskite film of excellent electronic quality with a power conversion efficiency(PCE) of up to 20.32%. Furthermore, the O...ΗAΝ hydrogen bonding interactions at the grain boundaries suppress the decomposition of methylammonium cations and improve the recyclable dissolution–recrystallization of perovskite. As a result, the MAPbI_(3)-PVP based cells exhibited striking moisture stability and self-healing behavior, with negligible decay in efficiency after 500 h of operation in high humidity(65% ± 5% relative humidity) and rapid recovering ability after their removal from the humid environment.

Revealing dual capacitive mechanism of carbon cathode toward ultrafast quasi-solid-state lithium ion capacitors

High-performance lithium ion capacitors(LICs) have been seriously hindered by the very low capacity and unclear capacitive mechanism of carbon cathode.Herein,after the combination of experimental results and theoretical calculations,it is found that the critical pore size of 0.8 nm for PF_6~-ion adsorption decreases strong interactive repulsion of electrons and largely reduces adsorption energy barrier,which greatly improves the charge accommodation capacity in electrical double-layer behavior.Most importantly,the chemical-bond evolution process of C=O group has been firstly revealed by X-ray photoelectron spectroscopy(XPS),indicating that the introduction of C=O group can provide abundant redox active sites for PF_6~-ion adsorption accompanied with enhanced pseudocapacitive capacity.Attributed to the synergistic effect of dual capacitive mechanism,porous carbon sheet(PCS) cathode shows a reversible specific capacity of 53.6 mAh g^(-1) even at a high current density of 50 A g^(-1).Significantly,the quasisolid-state LIC manifests state-of-the-art electrochemical performances with an integrated maximum energy density of 163 Wh kg^(-1) and an outstanding power density of 15,000 W kg^(-1).This elaborate work promotes better fundamental understanding about capacitive mechanism of PF_6~-ion and offers a rational dual-capacitive strategy for the design of advanced carbon cathodes.

Anthraquinone derivatives supported by Ti3C2(MXene)as cathode materials for aluminum-organic batteries

Due to the advantages of aluminum in abundance in the earth’s crust and safety,how to exploit these advantages to develop high-performance rechargeable aluminum batteries to replace traditional batteries has become an urgent issue.The key to solving this problem is to find suitable materials as cathode for aluminum batteries.Here,we propose a strategy in which Ti_(3)C_(2)(MXene)is used as a loaded structure for the organic anthraquinone derivative Benzo[1,2-b:4,5-b’]dithiophene-4,8-dione(BDTO).This strategy enables the self-stacking of monolayer MXene into a layered structure while embedding organics into it.The unique structure enables efficient and reversible intercalation/deintercalation of Al^(3+).At the same time,it exhibits excellent electrochemical performance,and its reversible capacity reaches229.8 mAh g^(-1).Moreover,it can still maintain a capacity of 134.9 mAh g^(-1)after 500 cycles.In addition.compared with BDTO,the rate performance of MXene@BDTO has also been greatly improved.Meanwhile,this unique layered structure also brings better electro nic co nductivity and ionic diffusion coefficient.We also demonstrate that the battery mechanism is a reaction between three C=O and one Al^(3+) through multiple characterization methods and density functional calculations(DFT).The advantages of MXene@BDTO provide a better research basis for the study of rechargeable Aluminum-Organic batteries,and provide a good idea to explore the development of Aluminum-Organic batteries.

Mechanistic Insights into the Fluorescence Quenching of Rhodamine 6G by Graphene Oxide

The fluorescence quenching of Rhodamine 6G （R6G） by graphene oxide （GO） was interrogated by R6G fluorescence measurements using a set of controlled GO samples with varied C/O ratios as the quencher. The carbonyl groups on the GO nanosheet turned to play a dominant role in quenching the R6G fluorescence. The quenching in the static regime can be described by the ＂sphere of action＂ model. The significant absorption of the R6G fluorescence by the ground-state complex formed between R6G and GO was identified to be responsible for the static quenching mechanisms in quenching. This work offers the R6G/GO system. insights into the fluorescence

Preyssler-type heteropoly acid:A new,mild and efficient catalyst for protection of carbonyl compounds

Preyssler-type heteropoly acid is introduced as a new,mild and efficient catalyst for protection of a variety of carbonyl compounds with 1,3-propane dithiol.

Formation of β-Lactones by [2＋2] Cycloaddition of Dichloroketene with Unreactive Carbonyl Compounds

We report a modified process that dichloroketene generated in situ from trichloroacetyl chloride and Zn powder reacts with unreactivate carbonyl groups to afford dichloro-β-lactones in moderate to good yields. Subse- quently, monochloro-β-lactones, β-lactones and β-hydroxy ester are obtained by dechlorination under different reac- tion conditions.

Pd（OAc）2-Catalyzed Tandem Reactions for the Synthesis of Indol-3-yl Substituted 1H-Isochromenes and 1,2-Dihydroisoquinolines

A Pd（II） catalyzed tandem reaction of o-alkynylbenzaldehydes or o-alkynylbenzaldimines with substituted indoles initiated by the intermolecular addition of indoles to the carbonyl or imine group followed by the nucleopalladation of an intramolecular alkyne and quenching the carbon-palladium bond by protonolysis to regenerate the Pd（II） species was developed. The reaction can be carried out under mild conditions without the necessity of a redox system.

A novel approach towards dethioacetalization reactions with H_2O_2-SOC1_2 system

A simple and efficient protocol for the deprotection of dithioacetal,1,3-dithianes and 1,3-dithiolanes has been developed using H_2O_2-SOC1_2 reagent system.In addition to the absence of overoxidation products for oxidation-prone substrates,high chemoselectivity, the low cost and availability of the reagents,simplicity of the method,short reaction times,and excellent yields can also be considered as strong points for this method.