Control of Excited‐State Conformations in B,N‐Acenes

We present a new concept to control the conformations of molecules in the excited state through harvesting negative hyperconjugation. The strategy was realized with the 2,3,1,4‐benzodiazadiborinane scaffold, which was prepared by a new synthetic procedure. Photochemical studies identified dual light emission, which was assigned to well‐defined conformers. The emission at longer wavelength can be switched off by restricting the rotational degrees of freedom in the solid state as well as by controlling the energy levels of the excited states through adjusting the solvent polarity.     

A highly sensitive and selective fluorescent probe for Fe3+ containing two rhodamine B and thiocarbonyl moieties and its application to live cell imaging

A novel turn-on rhodamine B-based fluorescent chemosensor (RBCS) was designed and synthesized by reacting N-(rhodamine B)lactam-1,2-ethylenediamine and carbon disulfide. Upon addition of Fe³⁺ in EtOH/H₂O solution (2:1, v/v, HEPES buffer, 0.6?mM, pH 7.20), the RBCS displayed a significant fluorescence enhancement at 582?nm and a dramatic color change from colorless to pink, which can be detected by the naked eye. Significantly, the RBCS exhibited a highly selective and sensitive ability toward Fe³⁺. The detection limit of the probe was 2.05?×?10^?7?M. Job's plot indicated the formation of 1:1 complex between the RBCS and Fe³⁺. Moreover, the practical use of the RBCS is demonstrated by its application in the detection of Fe³⁺ in HeLa cells.     

含能材料六硝基六氮杂异伍兹烷分子的B3LYP研究

在B3LYP/6-31G^**水平上对六硝基六氮杂异伍兹烷(CL-20)分子进行结构优化、集居数分析、自然键轨道和振动频率计算,得到与实验值相符的稳定构型.根据计算结果,讨论了键特性对分子性质的影响.     

Norditerpenoid Alkaloids from the Roots of Aconitum hemsleyanum Pritz.var.Pengzhouense

In continuation of our studies on Aconitum hemsleyanum Pritz.var. pengzhouense, two new norditerpenoid alkaloids, pengshenines A(1) and B(2),have isolated from the roots of the plants and their strucures were elucidated by 1D-and 2D-NMR.     

Two New Steroidal Saponins from Tacca plantaginea

Two new C27 steroidal glycosides, named taccaoside A(1) and B(2), were isolated from the traditional Chinese herb Tacca plantaginea. The spectroscopic and chemical evidences revealed their structures to be 26-O-β-D-glucopyranosyl-(25R)-3β,26-dihydroxy furost-5,20-diene-3-O-[α-L-rhamnopyranosyl(1→2)]-[α-L-rhamnopyranosyl(1→3)]-β-D-glucopyranoside(1) and 26-O-β-D-glucopyranosyl-(25R)-3β,26-dihydroxy furost-5,20-diene-3-O-[α-L-rhamnopyranosyl-(1→2)]-[β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→3)]-β-D-glucopyranoside(2),respectively.     

Two Novel Myrinsol Diterpenes from Euphorbia prolifera

Two novel diterpenes,Euphorprolitherin A(1) and Euphorprolitherin B(2), were isolated from the roots of Euphorbia prolifera. Their structures were elucidated on the basis of spectroscopic methods.     

Reaction Mechanism Investigation Using Vibrational Mode Analysis for the Multichannel Reaction of CH_3O+CO

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langmuir aggregation of alkali blue 6b in proteins: Study and application

The formation of microelectrostatic fields in biopolymers causes the adsorption of stain molecules in protein. The interactions between the dye alkali blue 6B (AB6B) and four proteins, bovine serum albumin (BSA), human γ-globulin (γ-G), horse myoglobin (Mb) and ovalbumin (OVA), were studied by the microphase adsorption/spectral correction technique. It was observed that the interactions obey the Langmuir isothermal adsorption. The Langmuir equilibrium constants of all the aggregates were determined. Interestingly, the adsorption of AB6B has no relation to the array sequence of amino acid residues, and an electrostatic field consists of constant amino acid residues. The novel method has been applied satisfactorily to the determination of the total protein content in two different samples.

     

罗丹明B-过氧乙酸-氢氧化钠化学发光法测定痕量硫

基于硫离子对罗丹明B 过氧乙酸 NaOH化学发光有较强的增敏作用,建立了流动注射化学发光增强法测定痕量硫的新方法。该法的线性范围为3.0×10-8～8.0×10-7g/mL,检出限为3.5ng/mL,相对标准偏差为2.2%(1.0×10-7g/mLS2-,n=11)。此法已用于环境水样中痕量硫的测定。