石英玻璃中顺磁缺陷中心的ESR成像

用ESR成像方法探测了石英玻璃杜瓦受紫外光辐照后产生的局部晶格缺陷——F心的空间分布情况.从F心的有梯度场ESR谱和二维ESR图象可以看出,石英杜瓦中产生的F心空间分布是不均匀的,其浓度与辐照方向和辐照强度密切相关.从F心ESR散点图计算出的石英杜瓦横截面几何尺寸与实物基本相符.     

电子自旋共振光谱在研究血红素蛋白及其模拟化合物中的应用

介绍电子自旋共振（ＥＳＲ）的基本原理，及ＥＳＲ在血红素蛋白及其模拟化合物铁卟啉的结构、性能、中心铁离子的状态等研究中的应用，以及用ＥＳＲ参数进行晶体场合分析的方法。     

极化中子衍射及在电子自旋密度研究中的应用

极化中子衍射方法常用于研究含未配对电子化合物中电子自旋密度的分布．分子中电子自旋密度分布从一个独特的角度反映化合物的磁性质．本文介绍极化中子衍射方法的背景知识和基本原理．包括中子源、中子和X射线衍射、极化中子衍射,以及一些常用的实验数据处理方法．选用几个实例总结了用极化中子衍射方法得到的电子自旋密度分布在无机和有机化学中的应用．通过单分子磁体[Fe8O2（OH）12（tacn）6]^8＋和氰基桥联化合物K2[Mn（H2O）2]3[Mo（CN）7]2·6H2O,说明如何用该方法研究金属原子间的磁相互作用;并通过Ru（acac）3这个只含一个未配对电子的化合物来说明如何获得化合物中金属和配体上小的自旋密度;最后介绍了该方法在nitronylnitroxide自由基研究中的应用．     

导电聚合物膜修饰电极的研究Ⅲ: 杂多酸掺杂聚吡咯膜电极的电子自旋共振(ESR)特性研究

本文通过对不同条件下的Co(W_2O_7)_6~(10-)和CuW_(12)O_(40)~(6-)掺杂聚吡膜ESR谱线的分析并以相同条件下NO_3~-掺杂聚吡咯膜作为参照,表明杂聚阴离子不仅起着中和电性的作用,而且与聚吡咯分子链相作用形成某种加合物,它影响聚吡咯的电结构,这种加合物在过正或过负的电位下均不稳定.首次发现在CuW_(12)O_(40)~(6-)掺杂的干态聚吡咯膜具有Dysonian线型,表明膜中其它电结构的存在.     

吡嗪连接的二维多孔共轭有机骨架的制备及其顺磁特性

本文通过自下而上的溶液合成方法成功制备了具有良好结晶性的吡嗪连接的二维共轭骨架HATP-HKH固体粉末.通过X射线粉末衍射、傅里叶变换红外光谱、高分辨透射电镜、原子力显微镜、超导量子干涉仪磁强计测试、电子自旋共振光谱等手段对材料进行了表征.液相剥离法制备的HATP-HKH纳米片的厚度分布在0.8至1.4nm之间,且其具...     

导电聚合物膜修饰电极的研究Ⅲ: 杂多酸掺杂聚吡咯膜电极的电子自旋共振(ESR)特性研究

本文通过对不同条件下的Co(W~2O~7)~6^1^0^-和CuW~1~2O~4~0^6^-掺杂聚吡咯膜ESR谱线的分析并以相同条件下NO~3^-掺杂聚吡咯膜作为参照, 表明杂聚阴离子不仅起着中和电性的作用, 而且与聚吡咯分子链相作用形成某种加合物, 它影响聚吡咯的电结构, 这种加合物在过正或过负的电位下均不稳定。首次发现在CuW~1~2O~4~0^6^-掺杂的干态聚吡咯膜具有Dysonian线型, 表明膜中其它电结构的存在。     

Fe3O4超顺磁纳米晶的超声共沉淀法制备及表征

利用超声强化的共沉淀法结合阴离子表面活性剂十二烷基硫酸钠(SDS)修饰技术, 制备出Fe3O4超顺磁纳米晶, 采用X射线粉末衍射仪(XRD)、傅立叶转换红外线光谱仪(FT-IR)、高分辨透射电子显微镜(HRTEM)、N2吸附-脱附及热重-差示扫描同步热分析仪(TG-DSC)等方法对样品进行表征, 系统研究了样品的表面电性及磁学性质, 并探索了超顺磁纳米晶的生长机理. 结果表明: 所制备的Fe3O4超顺磁纳米晶结晶完整, 分散性良好, 平均粒径在10 nm左右; 其比表面积高达91.6 m2•g－1, 具有优异的热稳定性, 蒸馏水中等电点pHpzc＝5.7; 其饱和磁强度(Ms)可达65.0 emu•g－1, 属超顺磁性纳米材料; 超声强化及SDS表面修饰, 对Fe3O4超顺磁纳米晶的生长起着非常重要的作用. 这种Fe3O4超顺磁纳米材料可望被较好地应用于细胞或酶的固定化等生物和医药领域.     

Tb_1-_xDy_x(Fe_1-_yMn_y)_(1.95)合金的磁致伸缩和声学性质及在水声换能器中的应用

研究了Ｔｂ１－ｘＤｙｘ（Ｆｅ１－ｙＭｎｙ）１．９５合金的磁致伸缩、声学等性质及其在水声换能器中的应用。当外加的磁场强度≥８００ｋＡ·ｍ－１时,磁致伸缩系数值在（１３００～１８００）×１０－６范围,有效机电偶合系数值０８４～０９３,声速为２１６８～２８５６ｍ·ｓ－１,杨氏模量为（５０６～７２６）×１０１０Ｎ·ｍ－２;用合金棒材研制水声换能器,该换能器总长３００ｍｍ,总重２ｋｇ,其共振频率为２４ｋＨｚ,发射电流响应１７３ｄＢ,频宽１ｋＨｚ,电声效率４５％     

In-Situ Electron Spin Resonance Studies of Polyaniline

In-situ electron spin resonance studies of polyaniline at various applied potentials in media of pH 0.49, 2.09, 3.96, anf 9 are reported. The g factor of the esr signal is 2.0036 and does not vary with the applied potential. The peak to peak linewidth decreases to a minimum in a potential range which depends on the pH of the medium. On the other hand, the spin density increases to a maximum in the same potential range. The pH-potential range where the highly conductive form exists, matches very well the range of narrow linewidth and high spin density of the esr signal. The conductive form of polyaniline consists of highly mobile radical cations or polarons.     

Structure and Electron Spin Resonance of Annealed Sol-Gel Glasses Containing Ag

In this work, SiO₂ samples with silver, prepared using the sol-gel method, were analyzed after being thermally treated in air in the range of 100 to 800°C. The sol-gel starting solutions were prepared by mixing tetra-ethyl-orthosilicate (TEOS), water and ethanol. Samples with 4 different H₂O/TEOS molar ratios (3.3, 5, 7.5 and 11.7 respectively) and with different nominal Ag concentrations were prepared (1, 2 and 4%vol. of Ag). It was found that upon annealing, different silver spices were formed, such as Ag₂ ⁺, Ag⁺, Ag°, and metallic silver aggregates. The identification of these spices was carried out by means of X-ray diffraction, Electron Paramagnetic Resonance (EPR), optical emission and optical absorption. It was also found that the specific type of silver spices observed depends on the structure of the SiO₂ matrix and on the annealing temperatures. It was found that samples prepared from precursor solutions with a low H₂O/TEOS ratio have a more open structure, and therefore silver diffuses faster and forms agglomerates at lower temperatures. Samples prepared from solutions with larger H₂O/TEOS ratios have a more dense structure, which allows the formation of atomic or molecular spices in addition to silver particles. A systematic study of this system was carried out using EPR on samples prepared from solutions having different H₂O/TEOS molar ratios, various Ag concentrations and subjected to different thermal treatments.     

Electron Spin Resonance Spectra of Some Free Radical in Pure C60 and Mixture of C60/C70

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｒｅｃｅｎｔｄｉｓｃｏｖｅｒｙｏｆａｃｌａｓｓｏｆｃａｒｂｏｎｃｏｎｔａｉｎｉｎｇｍｏｌｅｃｕｌｅｓｋｎｏｗｎａｓｔｈｅｆｕｌｅｒｅｎｅｓｈａｓｐｒｏｄｕｃｅｄａｓｅｒｉｅｓｏｆｍａｔｅｒｉａｌｓｗｉｔｈａｗｉｄｅｒａｎ...     

ESR study of electron interaction in a Tc/Al2O3 system

An investigation was made into the nature of paramagnetic centers in a Tc/Al₂O₃ system under varying conditions as to heat treatment and technetium content, and in O₂ and CO adsorption environments. It was found that in the case of reduction at 573 K Tc²⁺ ions and, conceivably, other ionic forms developed and stabilized on the carrier surface. After reduction at 973 K two types of electron center appeared, whose concentration increased as reduction was prolonged. Signals were observed in the low fields (3–20 mT) of the ESR spectra having g₁ 13.5 and g₂>30, which could be assigned to free charge carriers in a cluster of metal atoms or ions. Adsorption of O₂ at 300 K caused O ₂ ^– ion radicals to form on the surface of the reduced Tc/Al₂O₃ samples, both electron centers and technetium ions constituting the electron donors. In the case of CO adsorption paramagnetic (CO) ₂ ^– particles appeared on the Tc/Al₂O₃ samples after prolonged exposure. On reaction with O₂ two types of O ₂ ^– ion-radical with differing thermal stability were formed.Institute of Physical Chemistry, Russian Academy of Sciences, Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 1972–1978, September, 1992.     

Investigation of paramagnetic centers in supported catalysts based on mixed heteropolycompounds with d-metals

The ESR method was used to study bulky samples of the Fe−Mo heteropolycomplex and the related supported catalyst. The supported catalyst manifests a considerably higher thermal stability than the bulky sample of the individual heteropolycompound. The high thermal stability of paramagnetic centers in the supported Fe−Mo catalyst under the high-temperature action (up to 823 K) of water vapor was discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1365–1368, July, 1998.     

顺磁共振和紫外光谱法研究SDS-PEO体系的相互作用

合成更疏水的自旋探针4 羰基 2,2,6,6 四甲基哌啶氮氧自由基 2,4 二硝基苯腙.用顺磁共振（ESR）和紫外光谱法研究了十二烷基硫酸钠（SDS） 0.5 ％(w,质量分数)聚氧乙烯（PEO）体系的分子间相互作用. ESR结果表明,此水溶液体系的微极性随SDS浓度增大而减小,并且SDS与PEO聚集体具有更加紧密的堆积结构使其结合处具有较大的微粘性, SDS与PEO间的相互作用导致PEO分子链伸展. UV表明自旋探针分子可能靠近胶束的表面存在, 2,4 二硝基苯肼基团可能位于靠近SDS的硫酸根基团,定向于SDS胶束的表面,氮氧自由基基团短距离渗透到SDS胶束的碳氢核.     

Electron Spin Resonance(ESR)Spectroscopy of the Transition-metal Complexes and Clusters I.Systematic Investigations of Real-and Complex-Orbital Methods for Calculating the d-Orbital Energies of a Low-spin(S=1/2)nd~5(t_2~5,~2T_2)(n=3

１ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｃａｌｃｕｌａｔｉｏｎｓｉｎｔｈｅｆｉｒｓｔｐａｐｅｒｓｈｏｗｅｄｔｈａｔｒｅａｌ ａｎｄｃｏｍｐｌｅｘ ｏｒｂｉｔａｌｍｅｔｈｏｄｓｄｅｒｉｖｅｄｆｒｏｍａｍｏｄｅｌｏｆｅｌｅｃｔｒｏｎｉｃ ｉｎｔｅｒｓｕｐｐｌｅｍ...     

Electron spin resonance analysis of paramagnetic Pd(I) species in Pd(II)-exchanged H-rho zeolite

Zeolite rho was synthesized and Pd(II) exchanged into it. Pd(II) was reduced to paramagnetic Pd(1) by a thermal activation process. The interactions of Pd(I) in zeolite H-rho with oxygen, water, methanol, ammonia, carbon monoxide and ethylene have been studied by electron spin resonance (ESR) and electron spin echo modulation (ESEM) spectroscopies. The ESR spectrum of an activated sample shows the formation of one Pd(I) species. Pd(I) interacts with water vapor or molecular oxygen to form Pd(II)–O₂, indicating decomposition of water. Equilibration with methanol results in a broad isotropic ESR signal which is attributed to the formation of small palladium clusters. ESEM shows that the Pd clusters coordinate one molecule of methanol. Adsorption of ammonia produces a Pd(I) complex containing four molecules of ammonia based upon resolved nitrogen superhyperfine coupling. Adsorption of carbon monoxide results in a Pd(I) complex containing two molecules of carbon monoxide based upon resolved¹³C superhyperfine coupling. ESR and ESEM results indicate that exposure to ethylene leads to two new Pd(I) species each of which coordinates one molecule of ethylene.     

Electron paramagnetic resonance study of amphiphiles partitioning behavior in desiccation-tolerant moss during dehydration

Desiccation tolerance is a crucial characteristic for desert moss surviving in arid regions. Desiccation procedure always induces amphiphiles transferring from the polar cytoplasm into lipid bodies. The behavior of amphiphiles transferring can contribute to the enhancement of desiccation tolerance and the reduction of plasma membrane integrity simultaneously. The effects of amphiphiles partitioning into the lipid phase during water loss has been studied for pollen and seeds using electron paramagnetic resonance (EPR) spectroscopy. However, desiccation-tolerant high plants occur among mosses, several angiosperms and higher plants seeds or pollens. They have different strategies for survival in dehydration and rehydration. A desiccation-tolerant moss Tortula desertorum was used to investigate the behaviors of amphiphilic molecules during drying by spin label technology. There are small amount of amphiphilic probes partitioning into membrane during moss leaves dehydration, comparing with that in higher plants. Cytoplasm viscosity changed from 1.14 into glass state only dehydration less than 60 min. Moss leaves lost plasma membrane integrity slightly, from 0.115 to 0.237, occurred simultaneously with amphiphiles partition. The results showed the more advantages of mosses than higher plants in adapting fast dehydration. We propose that EPR spin label is feasible for studying the amphiphiles partitioning mechanisms in membrane protection and damage for desiccation-tolerant mosses.     

Study of phase separation in polyurethane using paramagnetic labels. Effect of soft segment molecular weight,structure, and thermal history

The morphology of segmented polyurethane (PU) elastomers was studied by means of ESR at various temperatures ranging from 100K-450K. The PU's were based on 4,4'-diphenylmethane diisocyanate (MDI), poly (oxytetramethylene) glycols (PTMO) and hydroxyl-terminated random compolymers of tetrahydrofuran and 3-methyl-tetrahydrofuran (THF/Me-THF). Purified 1,4-butanediol (BD) was used as a chain extender. The nitroxide probe, 4-hydroxy-2-2',6-6'-tetramethylpiperidine-1-oxyl (TEMPOL), was used to label the polyurethanes by reaction with an NCO group of MDI. Analysis of the electron spin resonance (ESR) spectra suggested that the label situates at heterogeneous sites, which means that a two-phase domain is present. The morphologies at 300K and 400K were compared. It was found from ESR spectra that polyurethanes made from soft segments having higher MW exhibited greater phase separation at 300K than their corresponding elastomers made from lower MW soft segments. However, at 400K the more isotropic ESR spectra for the PUs containing higher MW soft segments suggested that the PUs were more mobile than their analogs having lower MW soft segments. The introduction of 3-methyl side groups decreased the phase mixing at 400K due to steric hindrance.