Sr／Ca比变化对红色荧光粉Ca1-xSrxS：Eu^2＋的影响

在CO气氛下采用固相反应法合成了发红光的Ca1-xSrxS:Eu^2 荧光粉，研究了基质阳离子Sr／Ca比变化对其晶体性质及发光性能的影响。结果表明，随着Sr／Ca比的减少，荧光粉的晶胞参数逐渐降低；同时，由于受电子云膨胀效应和晶体场影响，发射主峰向长波方向移动，红色比逐渐增大，色纯度提高。     

Photochromic crown ethers

An amphiphilic crown-containing styryl dye (1) was synthesized, and the effects of irradiation, temperature, and alkali and alkali-earth metal ions on the conductivity and optical spectra of its solutions in dioctyl phthalate were studied. Compound1 in thetrans-form almost completely exists as ion pairs (IP). Irradiation at a long-wavelength absorption maximum (λ_max) results in a reversible increase in the conductivity and, hence, a degree of dissociation of IP (α); these parameters decrease when complexes with metal ions are formed. The relaxation times for the photoinduced conductivity coincide with a decrease in the extinction within experimental error in the 20–60°C temperature range. The photoinduced increase in α is caused bytrans—cis-isomerization and an increase in steric hindrances for the interaction of the ClO₄ ⁻ anion with the N⁺ atom of benzothiazolium in thecis-form of1. The activation energies for the darkcis—trans-relaxation, absolute α values, and thermodynamic parameters of dissociation of IP in thetrans-form, as well as the α values in a photostationary mixture ofcis—trans-isomers, were estimated. The decrease in α after binding with metal ions is likely caused by the redistribution of the positive charge to benzothiazolium through the conjugated system of1. Correlations between the decrease in conductivity (decrease in α) and the hypsochromic shift Δλ_max after the formation of complexes between1 and metal ions were observed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1296–1301, July, 1997.     

Citrate selectivity of poly(neutral red) electropolymerized films

The synthesis and the spectroscopic and potentiometric characterization of electropolymerized films obtained from neutral red (NR) on Pt surface are described. FT Raman and NMR spectroscopy were used for evaluation of the resulting poly(NR) layers. Then potentiometry was applied to study the characteristics of the complexation of carboxylates with the poly(NR) films. A potentiometric poly(NR) sensor showing high selectivity for citrate anion was employed for its determination in soft drinks.     

Synthesis and modification of terrylenediimides as high-performance fluorescent dyes

Two new synthetic approaches to terrylenediimides, highly photostable fluorescent dyes, are described. For the first time terrylenediimide has been synthesised in a straightforward procedure that makes large quantities available. The second route includes an efficient cross-coupling reaction followed by a cyclodehydrogenation. Monofunctionalisation of the imide structure allows terrylenediimides now to be coupled with a variety of compounds, for example, by Suzuki cross-coupling, which can lead to an array of terrylenediimides with new functional groups such as hydroxy, amino, or carboxy groups needed to link up with other molecules. The functionalisation in the bay region is used to tune the properties of terrylenediimides and extend the range of applications, for example, by introducing water solubility. These tetrasubstituted terrylenediimides offer, depending on the substituents used, exciting features such as good solubility in common organic solvents, water solubility, or NIR absorption.     

光谱法和电化学法研究中性红与小牛胸腺DNA的相互作用

利用紫外 可见和圆二色光谱(CD)法和伏安方法,研究了小分子染料中性红(NR)与小牛胸腺DNA(CTDNA)的相互作用。实验表明在NR低浓度下,NR能嵌入至核酸双螺旋的碱基内部在G C处与核酸结合,而在较高浓度情况下,嵌入的NR分子与后来的在核酸双螺旋外部的NR分子相互作用发生聚集,从而堆积在DNA双螺旋的表面,同时使核酸的构象由B型转变为Z型。用光谱滴定的方法获得NR与CTDNA作用内部结合常数,分别为:Ka1=2 4×104mol·L-1·cm-1和Ka2=2 1×10-2mol·L-1·cm-1。     

吸附伏安法测定表面活性剂的临界胶束浓度

以易溶于有机溶剂，微溶于水的氧化－还原指示剂中性红为探针，用吸附伏安法测定了阴离子表面活性剂的临界胶束浓度。测量的基本原理是：存在于表面活性剂溶液中的微量中性红在悬汞电极上的吸附伏安峰电流对表面活性剂浓度的曲线在临界胶束浓度处有一拐点。     

天线若丹明染料分子内能量与电荷传递的研究

染料三重态在染料激光的应用中起着重要作用，尤其是三重态一Z重态（T－T）吸收常常会造成谐振腔损耗＊．为了减少由基态吸收而造成的话振腔损耗，带有紫外吸收天线分子的三发色团染料已在研究问，2，5·二苯基螨喳（PP0）在紫外区（如308删）有很强的吸收，PPO－rhod．系列染料（见图1）在紫外区的吸收就很强，由PPO到若丹明母体的单线态一单线态（S功能量传递使这类三发色团染料具有较大的荧光量子效率，较小的基态重复吸收耗能卜，司．然而，在610N640nm区域中这些天线若丹明染料的激光输出效率远远小于若丹明Rh630＊，其原因正是…     

Antioxidant activity and Neurite outgrowth-enhancing activity of scorbamic acid and a red pigment derived from ascorbic acid

Abstract

L-Ascorbic acid (AA), known as vitamin C, can form browning products by a non-enzymatic process during storage and the browning products cause deterioration of agricultural products. In the browning reaction, a red pigment, 2,2´-nitrilodi-2(2´)-deoxy-L-ascorbic acid ammonium salt (NDA), is generated from AA via L-scorbamic acid (SCA) as an intermediate. However, the biological activities of SCA and NDA have not yet been clarified. In this study, we assayed the antioxidant activities of SCA and NDA using ABTS radical cation and their neurite outgrowth-enhancing activities in PC12 cells. SCA showed stronger radical-scavenging activity than that of AA, while NDA hardly showed any activity. SCA and NDA enhanced the neurite outgrowth induced by dibutyryl cyclic AMP after their incorporation into cells in the same manner as that of AA. The results indicated that SCA has antioxidant activity and that SCA and NDA have neurite outgrowth-enhancing activity.     

C74(BN)2的UV和IR 光谱研究

Equilibrium geometries of 16 possible isomers for C74（BN）2 were studied by INDO series of methods, to indicate that the most stable three geometries are those where boron and nitrogen atoms substitute carbon atoms located at the same hexagon near the longest axis of C78 （C2v） to form B-N-B-N unit. Electronic spectra of C74（BN）2 were investigated with INDO/CIS method. The reason for the red shift of UV absorptions for C74（BN）2 compared with those of C78 （C2v） was discussed. IR spectra for 9,8,28,29-C74（BN）2 and 28,29,30,31-C74（BN）2 were calculated on the basis of AM1 geometries.