茉莉酸甲酯和超氧化物歧化酶相互作用的光谱法研究

通过荧光光谱法和紫外吸收光谱法研究了超氧化物歧化酶和茉莉酸甲酯之间的相互作用。经过荧光光谱法的研究表明,超氧化物歧化酶和茉莉酸甲酯的相互作用是一个静态猝灭的过程,它们之间是以氢键和范德华力结合的,同时得到超氧化物歧化酶和茉莉酸甲酯的结合位点数n,表观结合常数K和热力学参数ΔH,ΔG,ΔS。而根据非放射性能量转移的F rster理论和同步荧光光谱证明茉莉酸甲酯和超氧化物歧化酶的相互作用位点同时接近超氧化物歧化酶色氨酸(Trp)和酪氨酸(Tyr)残基。     

双咪唑苯和双三唑苯及其衍生物非线性光学性质的密度泛函研究

采用密度泛函理论(DFT)的UB3LYP(B3LYP)/6-31+G**方法对双咪唑苯和双三咪唑苯双自由基及其衍生物几何结构进行优化,并结合有限场(FF)方法计算这些体系的非线性光学(NLO)系数.结果表明,引入给、受体取代基都能使体系的极化率α和二阶超极化率γ增大.在双自由基体系中,引入给体NH2的α和γ值大于引入受体NO2的值,与闭壳层体系中结果相反.分析自由基成分和电荷对体系的二阶超极化率γ影响的结果表明,处于中间双自由基成分的分子比相似共轭性的闭壳层分子有更大的二阶超极化率γ;带电荷的双自由基体系引入给、受体之后,与中性自由基体系相比具有更大的二阶超极化率γ.     

Weak Mp-groups

Abstract

Let G be a finite group and p be a prime. We prove in this note that if every irreducible monolithic p-Brauer character of G is monomial then G is solvable.

Communicated by J. Zhang     

A spectroscopic study of the interaction of octacarboxylic metal phthalocyanine with bovine serum albumin

The interaction of octacarboxylic metal phthalocyanines (MPc(COOH)₈, M =?Al(III) and Co(II) with bovine serum albumin (BSA) has been studied. From the binding isotherm based on spectrophotometric titration, the association constant and a number of ligands per binding site were calculated at 25°C. By using the well studied Hemin chloride (HE), Ibuprofen(IB) and L-tryptophan (TRP) as competitive ligands, the binding sites of AlPc(COOH)₈ were found to be on domain I and II of BSA, while on domain I for Co(COOH)₈.     

The stabilities and formation kinetics of some macrocycles with copper(II): crystal structures of some pendant arm macrocycles

Kinetics of complex formation and stability constants of tetra-(2-hydroxpropyl) substituted cyclam (L³) and cyclen (L⁴) with copper(II) have been studied in aqueous solution at room temperature. These data are compared to the corresponding parent compounds (cyclam L¹ and cyclen L²) in an attempt to define the effect of pendant arm upon kinetics and stability constants of the complexes. The kinetics were observed by stopped-flow measurements followed at multiwavelengths. These ligands were chosen to furnish information concerning effect of pendant groups and cavity size on the kinetics and stability of the complexes. Stopped-flow and spectrophotometric titration techniques were used for evaluation of the kinetics and stability constants, respectively. The apparent rate constants increase as CuL³?>?CuL⁴?>?CuL¹?>?CuL². Activation parameters and stability constants of the complexes were estimated. The effect of cavity size on the rate of reaction can be observed in CuL³?>?CuL⁴ and CuL¹?>?CuL² and the effect of pendant groups in CuL³?>?CuL¹ and CuL⁴?>?CuL². Mechanism of the complex formation reaction is proposed. The enhanced stability of the copper(II) complexes formed with L¹ and L² macrocyclic ligands is compared to those formed with analogous pendant arm species.     

CDSD-4000: High-resolution, high-temperature carbon dioxide spectroscopic databank

We present a high-resolution, high-temperature version of the Carbon Dioxide Spectroscopic Databank called CDSD-4000. The databank contains the line parameters (positions, intensities, air- and self-broadened half-widths, coefficients of temperature dependence of air- and self-broadened half-widths, and air-broadened pressure shifts) of the four most abundant isotopologues of CO₂. A reference temperature is 296 K and an intensity cutoff is 10⁻²⁷ cm⁻¹/molecule cm⁻² at 4000 K. The databank has 628,324,454 entries, covers the 226-8310 cm⁻¹ spectral range and designed for the temperature range 2500-5000 K. Format of CDSD-4000 is similar to that of HITRAN-2008. The databank has been generated within the framework of the method of effective operators and based on the global fittings of spectroscopic parameters (parameters of the effective Hamiltonians and effective dipole moment operators) to observed data collected from the literature. The databank is useful for studying high-temperature radiative properties of CO₂, including exoplanets atmospheres, aerothemal modeling for Mars entry missions, high-temperature laboratory spectra, and industrial applications. CDSD-4000 is freely accessible via the Internet site ftp://ftp.iao.ru/pub/CDSD-4000.     

Structure elucidation and NMR assignments of a new dihydrochalcone from Empetrum nigrum subsp. asiaticum (Nakai ex H.Ito) Kuvaev

Abstract

A new dihydrochalcone, namely 2',5'-dimethyl-3'-methoxy-4',6'-dihydroxyl-dihydrochalcone (1) together with five known compounds were isolated from the CHCl₃ extract from Empetrum nigrum L. var. japonicum K. Koch (E. nigrum). The structures of 1 was elucidated by spectroscopic methods, including UV, IR, HR-ESI-MS and extensive 1D and 2D NMR techniques.     

A first-principle prediction on the magnetism and electronic structure of Ti-doped CoO with two O vacancies

The electronic structure and magnetism in Co₁₄Ti₂O₁₄ systems are investigated by using the first-principles calculations. The system of 2 × 2 × 2 Co₁₄Ti₂O₁₆ supercell doped with Ti at 9 and 11 position shows a half-metallic character with a high spin polarization. Based on the above system, we remove two O atoms to form two O vacancies. The two O vacancies near Ti have a huge effect on the electronic structure and magnetic properties of Co₁₄Ti₂O₁₄ system. When O vacancies locate at 1 and 3 positions, the system shows a half-metallic character. For the O vacancies at 6 and 8 positions, the system shows a semiconducting character. The system with O vacancies at 9 and 11 positions is a typical spin gapless semiconductor.     

Synthesis and application of Vis/NIR dialkylaminophenylbuta-1, 3-dienyl borondipyrromethene dyes

Mono- and bis-dialkylaminophenylbuta-1,3-dienyl boron-dipyrromethenes(BODIPYs) 1–12 were synthesized in 36%–42% yields by a Knoevenagel-type condensation. The absorption and emission maxima(labs= 614–739 nm; lem= 655–776 nm in CHCl3) of 1–12 covered from the visible to the nearinfrared region. Probe 1 was ratiometric Vis p H probes. Such probe was almost non-fluorescent. Upon the protonation of the tertiary amine function of 1, the strong fluorescence(Φf= 0.97) was released and the florescence intensity was dramatically increased by one thousand folds. The sharp isosbestic points were discovered at 590 nm, which was a ratiometric p H probe.