Selectivity of a Resorcinarene Host for Pentanol Isomers

The resorcinarene host H=1⁴,1⁶,5⁴,5⁶-tetrahydroxy-2,4,6,8-tetrapentyl-3⁴,3⁶,7⁴,7⁶-tetra(p-toluenesulfonyloxy)-1,3,5,7(1,3)-tetrabenzenacyclooctaphane was found to form inclusion compounds with seven pentanol isomers, namely 1-pentanol (H·2(1PENT)), 2-pentanol (H·2(2PENT)), 3-pentanol (H·2(3PENT)), 2-methyl-1-butanol (H·2(2M1B)), 3-methyl-1-butanol (H·2(3M1B)), 2-methyl-2-butanol (H·2(2M2B)) and 3-methyl-2-butanol (H·2(3M2B)). These compounds were characterized by thermal analysis, which showed that they all have host-guest (H:G) ratios of 1:2, and their structures were elucidated and compared. Competition experiments were carried out to investigate the selectivity of this host for some of the pentanol guests and thereby investigate the capability of this host for the separation of pentanol isomers.     

Complexation with diol host compounds. Part 18. Structures and thermal analysis of trans-9,10-dihydroxy-9,10-di-p-tolyl-9,10-dihydroanthracene and its inclusion compounds with acetone,diethyl ether and pyridine

Abstract

The structure of the host compound trans-9,10-dihydroxy-9,10-di-p-tolyl-9,10-dihydroanthracene and those of its inclusion compounds with acetone, diethyl ether and pyridine have been elucidated. The non-porous α-phase of the host has a structure in which the molecules are packed in layers parallel to the (100) plane, but exhibit no intermolecular hydrogen bonding. The host:guest stoichiometry of each inclusion compound is 1:2, and the structures are each stabilised by O-H…O or O-H…N hydrogen bonds between host and guest. The thermal decompositions of the acetone and diethyl ether compounds are characterised by single endotherms of the guest-release reaction, but the pyridine inclusion compound has a more complex decomposition, characteristic of similar pyridine inclusion compounds.     

Baylis-Hillman-derived N,N′-disubstituted piperazines: structural and preliminary computational studies

Exploratory studies towards the preparation of potential HIV-1 protease and integrase inhibitors have led to the synthesis of Baylis-Hillman-derived N,N′-disubstituted piperazines. X-ray crystallographic, computer modelling and NMR techniques have been used to elucidate questions concerning configurational preferences, reaction pathways and the apparent difference in susceptibility towards aza-Michael reactions exhibited by methyl acrylate and methyl vinyl ketone (MVK) derived Baylis-Hillman substrates.     

调制掺杂ZnSe/BeTe Ⅱ型量子阱结构中的内秉电场和新型带电激子

报道了调制掺杂的ZnSe/BeTe/ZnSe Ⅱ型量子阱(type-Ⅱ QW)在低温(2—5 K)条件下的光致发光(PL),光致发光激发(PLE)和磁性光致发光(magneto-PL)光谱的实验结果.　观察到非掺杂样品的PL有两个很强的主发光峰而掺杂样品只有一个的奇异发光.　PL直线偏振度和PLE的测量结果都表明了这些空间间接型跃迁PL是来自两个异质结界面的贡献,非掺杂样品的两个主发光峰的分离则是起因于QW结构中的内秉电场(built-in electric field).在平行于QW生长方向的强磁场中, 关键词： 光致发光 二维电子气 带电激子 Ⅱ型量子阱     

In Silico and Experimental Investigation of the Biological Potential of Some Recently Developed Carprofen Derivatives

The efficient regioselective bromination and iodination of the nonsteroidal anti-inflammatory drug (NSAID) carprofen were achieved by using bromine and iodine monochloride in glacial acetic acid. The novel halogenated carprofen derivatives were functionalized at the carboxylic group by esterification. The regioselectivity of the halogenation reaction was evidenced by NMR spectroscopy and confirmed by X-ray analysis. The compounds were screened for their in vitro antibacterial activity against planktonic cells and also for their anti-biofilm effect, using Gram-positive bacteria (Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212) and Gram-negative bacteria (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853). The cytotoxic activity of the novel compounds was tested against HeLa cells. The pharmacokinetic and pharmacodynamic profiles of carprofen derivatives, as well as their toxicity, were established by in silico analyses.     

N-Aryl and N-Alkyl Carbamates from 1 Atmosphere of CO2

We have successfully isolated and characterized the zinc carbamate complex (phen)Zn(OAc)(OC(=O)NHPh) ( 1 ; phen=1,10-phenanthroline), formed as an intermediate during the Zn(OAc)₂/phen-catalyzed synthesis of organic carbamates from CO₂, amines, and the reusable reactant Si(OMe)₄. Density functional theory calculations revealed that the direct reaction of 1 with Si(OMe)₄ proceeds via a five-coordinate silicon intermediate, forming organic carbamates. Based on these results, the catalytic system was improved by using Si(OMe)₄ as the reaction solvent and additives like KOMe and KF, which promote the formation of the five-coordinated silicon species. This sustainable and effective method can be used to synthesize various N-aryl and N-alkyl carbamates, including industrially important polyurethane raw materials, starting from CO₂ under atmospheric pressure.     

On the Origin of the Non-Arrhenius Na-ion Conductivity in Na3OBr

The sodium-rich antiperovskites (NaRAPs) with composition Na₃OB (B=Br, Cl, I, BH₄, etc.) are a family of materials that has recently attracted great interest for application as solid electrolytes in sodium metal batteries. Non-Arrhenius ionic conductivities have been reported for these materials, the origin of which is poorly understood. In this work, we combined temperature-resolved bulk and local characterisation methods to gain an insight into the origin of this unusual behaviour using Na₃OBr as a model system. We first excluded crystallographic disorder on the anion sites as the cause of the change in activation energy; then identified the presence of a poorly crystalline impurities, not detectable by XRD, and elucidated their effect on ionic conductivity. These findings improve understanding of the processing-structure-properties relationships pertaining to NaRAPs and highlight the need to determine these relationships in other materials systems, which will accelerate the development of high-performance solid electrolytes.