Theoretical study on cation-anion interaction and vibrational spectra of 1-allyl-3-methylimidazolium-based ionic liquids

In order to deepen the understanding of the cation-anion interaction in ionic liquids, the structures of cation, anions, and cation-anion ion-pairs of 1-allyl-3-methylimidazolium-based ionic liquids are optimized using density functional theory (DFT), and their most stable geometries are discussed. The structural parameters, hydrogen bonds and interaction energies of 1-allyl-3-methylimidazolium dicyanamide ([Amim]DCA), 1-allyl-3-methylimidazolium chloride ([Amim]Cl), 1-allyl-3-methylimidazolium formate ([Amim]FmO) and 1-allyl-3-methylimidazolium acetate ([Amim]AcO) ion pairs are studied. The vibrational frequencies of [Amim]DCA and [Amim]Cl have been calculated and scaled values have been compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes.     

Rhodium-catalyzed oxidative C2-acylation of indoles with aryl and alkyl aldehydes

A rhodium-catalyzed oxidative C2-acylation of indoles with aryl and alkyl aldehydes via C-H bond activation is described. The reaction is highly atom-economic and provides easy access to a wide variety of 2-aroylindoles.     

Synthesis of Entecavir (BMS-200475)

A synthesis of Entecavir (BMS-200475) was achieved starting from 1,3-propanediol in 15 steps and 23.4% overall yield. A unique feature of the synthetic route is that the five-membered carbocyclic core is installed by an intramolecular nitrile oxide cycloaddition (INOC) reaction and the guanine moiety is introduced by a Mitsunobu reaction. The route is characteristic of low cost, high yield and easy operation.     

Theoretical study on the improvement of the doping efficiency of Al in 4H-SiC by co-doping group-ⅣB elements

The p-type doping efficiency of 4H silicon carbide(4H-SiC)is rather low due to the large ionization energies of p-type dopants.Such an issue impedes the explora...     

Heteroepitaxial Growth of Multiblock Ln‐MOF Microrods for Photonic Barcodes

Micro/nanoscale multicolor barcodes with unique identifiability and a small footprint play significant roles in applications such as multiplexed labeling and tracking systems. Now, a strategy is reported to design multicolor photonic barcodes based on 1D Ln‐MOF multiblock heterostructures, where the domain‐controlled emissive colors and different block lengths constitute the fingerprint of a corresponding heterostructure. The excellent heteroepitaxial growth characteristics of MOFs enable the effective modulation of the coding structures, thereby remarkably increasing the encoding capacity. The as‐prepared multicolor barcodes enable an efficient authentication and exhibit great potential in fulfilling the functions of anti‐counterfeiting, information security, and so on. The results will pave an avenue to novel hybrid MOFs for optical data recording and security labels.     

Helium/hydrogen synergistic effect in reduced activation ferritic/martensitic steel investigated by slow positron beam

Here, we investigated the irradiation defect in reduced activation ferritic/martensitic steels by slow positron beam. Three ion-irradiation experiments were carried out: (i) He²⁺ irradiation, (ii) H⁺ irradiation and (iii) He²⁺ irradiation followed by H⁺ irradiation, at temperature 450?°C. The presences of vacancy defects, represented by ?S_He+H parameter, induced by sequential irradiations was larger than the sum of defects, ?S_He parameter + ?S_H parameter, caused by single He ions and single H ions. The synergistic effect of He and H was confirmed clearly from the perspective of positron annihilation spectroscopy.     

(Liquid + liquid) equilibria for (acetate-based ionic liquids + inorganic salts) aqueous two-phase systems

In the present work, (liquid + liquid) equilibrium data have been determined experimentally for aqueous two-phase systems formed by the imidazolium ionic liquids of [C_nmim][CH₃COO] (n = 4, 6, 8) and inorganic salts of K₃PO₄, K₂HPO₄, and K₂CO₃ at T = 298.15 K. Combined with available data in the literature, the effect of alkyl chain length of cations, type of anions of the ionic liquids, and nature of the inorganic salts were examined on the binodal curves of the systems. Then the binodal curves were fitted to a four-parameter empirical equation, and the tie-lines were described by the Othmer–Tobias and Bancroft equations. In addition, the extraction capacity of the {[C_nmim][CH₃COO] (n = 4, 6, 8) + K₃PO₄} aqueous two-phase systems was evaluated through their application to the extraction of l-tryptophan. The high extraction efficiency suggests that these aqueous two-phase systems are feasible to be used in the extraction and separation process.     

Rhodium‐Catalyzed Directed Sulfenylation of Arene CH Bonds

The rhodium‐catalyzed intermolecular direct C?H thiolation of arenes with aryl and alkyl disulfides was developed for the first time to provide a convenient route to aryl thioethers. This strategy is compatible with many different directing groups and exhibits excellent functional group tolerance. More significantly, mono‐ or dithiolation can be selectively achieved, thus providing a straightforward way for selective preparation of aryl thioethers and dithioethers.     

Rhodium‐Catalyzed Direct Amination of Arenes with Nitrosobenzenes: A New Route to Diarylamines

A Rh^III‐catalyzed addition of aryl C?H bonds to nitrosobenzenes, followed by cleavage of the resulting hydroxylamines in situ, has been reported. Different directing groups, such as N‐based heterocycles and ketoximes, can be used in this C?H amination process, providing valuable diarylamines in excellent yields. Most importantly, this process provides a new method for attaching arylamine groups to aromatic rings.