Ca3La3(BO3)5中Eu3+的光致发光

本文详细地研究了紫外光激发下,Ca_3La_3(BO_3)_5中Eu~(3+)的发光光谱和激发光谱与组成、结构的关系.发现Eu~(3+)在此基质中可能不止一个发光中心;Eu~(3+)自身浓度猝灭的机理为电四极-四极相互作用.     

Sequential ene, Diels-Alder reactions of AF4-yne with 1,3,5-cycloheptatriene

(4,5-Dehydro)-1,1,2,2,9,9,10,10-octafluoro [2.2]paracyclophane (AF4-yne) undergoes an ene reaction with 1,3,5-cycloheptatriene, the adduct of which subsequently undergoes a further Diels-Alder reaction with a second equivalent of AF4-yne to give two stereoisomeric 2:1 adducts. A very small amount of the classic 1:1 Diels-Alder adduct also can be isolated from the reaction. Structure assignments of all products were determined by NMR through a series of H1-H1, H1-C13 one bond, and H1-C13 two and three bond correlation experiments as well as H1-H1 NOE experiments.     

Cu(I)-catalyzed cycloguanidination of olefins

This paper describes a novel cycloguanidination process using CuCl as catalyst and diaziridinimines as the nitrogen source. A variety of conjugated dienes, trienes, and terminal olefins can be effectively diaminated under mild reaction conditions. For dienes and trienes, the reaction occurs at the terminal double bond with high regioselectivity.     

Formation of Hybrid Perovskite Tin Iodide Single Crystals by Top‐Seeded Solution Growth

Hybrid perovskites have generated a great deal of interest because of their potential in photovoltaic applications. However, the toxicity of lead means that there is interest in finding a nontoxic substitute. Bulk single crystals of both cubic CH₃NH₃SnI₃ and CH(NH₂)₂SnI₃ were obtained by using the top‐seeded solution growth method under an ambient atmosphere. Structural refinement, band gap, thermal properties, and XPS measurements of CH₃NH₃SnI₃ and CH(NH₂)₂SnI₃ single crystals are also reported in detail. These results should pave the way for further applications of CH₃NH₃SnI₃ and CH(NH₂)₂SnI₃.     

Designing new chiral ketone catalysts. Asymmetric epoxidation of cis-olefins and terminal olefins

This paper describes a new class of chiral oxazolidinone ketone catalyst for asymmetric epoxidation. High ee values have been obtained for a number of cyclic and acyclic cis-olefins. The epoxidation was stereospecific with no isomerization observed in the epoxidation of acyclic systems. Encouragingly high ee values have also been obtained for a number of terminal olefins. Mechanistic studies show that electronic interactions play an important role in stereodifferentiation.     

Phosphine oxide-Sc(OTf)<Subscript>3</Subscript> catalyzed enantioselective bromoaminocyclization of <Emphasis Type="Italic">tri</Emphasis>-substituted allyl <Emphasis Type="Italic">N</Emphasis>-tosylcarbamates

Phosphine oxide-Sc(OTf)₃ catalyzed regio- and enantioselective bromoaminocyclization of tri-substituted allyl N-tosylcarbamates is described. A wide variety of optically active tertiary 5-bromo-1,3-oxazinan-2-ones can be obtained with high regio-and enantioselectivity.     

The investigation of electrospun polymer nanofibers as a solid-phase extraction sorbent for the determination of trazodone in human plasma

A novel micro-extraction procedure was developed through the use of an electrospun polymer nanofiber as a solid-phase extraction (SPE) sorbent to directly extract trazodone from human plasma. The target compound was then monitored by a high performance liquid chromatography with ultraviolet detector (HPLC-UV) system. Parameters of influencing the extraction efficiency, such as fiber diameter, fiber packing amount, eluted solvent, pH and ionic strength were investigated. Under the optimized conditions, a linear response for trazodone over the range of 20-2000 ng mL⁻¹ was achieved with a γ² value of 0.9996. The precision of the method was examined with relative standard deviations of 5.7, 2.7, 2.2% corresponding to 50, 200, and 500 ng mL⁻¹, respectively, of trazodone spiked into 0.1 mL of plasma samples. The extraction recoveries of 58.3-75.2% and the relative recoveries of 94.6-105.5% were obtained. The limit of detection (LOD) was determined to be 8 ng mL⁻¹. A 15 min of HPLC gradient was successfully applied to determine trazodone from human plasma. Due to its simplicity, selectivity and sensitivity, the method may be applied to pharmacokinetic and pharmacodynamic studies of drugs.