新型环钯化二茂铁亚胺-膦配合物的质谱特征

采用电喷雾离子阱质谱法(ESI-MS)对两种环钯化二茂铁亚胺-膦配合物的质谱特征进行了研究,获得了它们的结构碎片信息,对其质谱裂解途径进行了解析.结果表明:在正离子检测方式下可以得到强的准分子离子峰[M-C l]+和[M-I]+簇,它们的(+)ESI-MSn(n=1~4)质谱主要产生碳-膦键断裂的碎片,同时也能观察到钯-磷键的断裂.这些特征为此类化合物及其结构类似物的结构推断提供了依据.     

三角帆蚌贝壳粉与其珍珠粉的微结构及其光谱学特征

采用扫描电镜(SEM)、热重分析(TG)、傅里叶变换红外光谱(FTIR)及白度测试对三角帆蚌贝壳与其养殖的珍珠研磨粉进行了对比研究。结果表明:1珍珠粉的υ2谱带较于贝壳粉的该谱带存在约1~3cm-1的蓝移,两者文石中的υ1与υ4谱带具有较好的一致性;2 SEM观察下,粉体的颗粒粒径大小与形貌特征并不能作为贝壳粉与珍珠粉区分鉴别的依据。3随煅烧温度的升高,贝壳粉与珍珠粉的白度先下降后升高,珍珠粉白度降低的速率高于贝壳粉,且煅烧后珍珠粉的白度最低值低于煅烧贝壳粉的白度最低值。     

Spectroscopic Characteristics of Hyperbranched Conjugated Polymers Studied by One- and Two-Photon Excitations

Spectroscopic properties of new hyperbranched conjugated polymers functionalized in periphery with N,N-dimethylaniline and tert-butyl-benzene as terminal groups are investigated by one- and two-photon excitations. The absorption, °uorescence excitation and emission spectra are examined in chloroform and N,N-dimethylformamide. The two-photon excitation measurements show that the new hyperbranched conjugated polymer possesses large two-photon excitation cross section which makes it a very attractive candidate for the potential application as nonlinear optical materials. As an example, the two-photon induced three-dimensional data storage is also demonstrated.     

Electrochemical and Spectroscopic Characteristics of Artemisinin Antimalarial Drug: Charge Transfer Redox Process

Artemisinin is a plant extract and popular in treating many diseases including malaria. It is a sesquiterpene lactone with several binding modes to several molecules. Oxidation and reduction of this molecule at different electrode materials was studied in tetrabutyl ammonium bromide in acetonitrile solution. The apparent standard heterogeneous rate constant for electron transfer (k_h) was found to be 23 cm s^?1. The value of the electron transfer coefficient (αn_a) was found to be 0.496. The diffusion coefficient (D) was found to be 3.34 × 10^?6 cm s^?1. Gold (Au), glassy carbon, and pyrolytic graphite electrodes exhibited distinguishable current densities. A value of E _1/2 = –0.81 V versus Ag/AgCl was obtained, and a value of n = 1.52 (2) was estimated.     

Spectroscopic Characteristics of Differently Produced Single‐Walled Carbon Nanotubes

Single‐walled carbon nanotubes (SWNTs) synthesized with different methods are investigated by using multiple characterization techniques, including Raman scattering, optical absorption, and X‐ray absorption near edge structure, along with X‐ray photoemission by following the total valence bands and C 1s core‐level spectra. Four different SWNT materials (produced by arc discharge, HiPco, laser ablation, and CoMoCat methods) contain nanotubes with diameters ranging from 0.7 to 2.8 nm. The diameter distribution and the composition of metallic and semiconducting tubes of the SWNT materials are strongly affected by the synthesis method. Similar sp² hybridization of carbon in the oxygenated SWNT structure can be found, but different surface functionalities are introduced while the tubes are processed. All the SWNTs demonstrate stronger plasmon resonance excitations and lower electron binding energy than graphite and multiwalled carbon nanotubes. These SWNT materials also exhibit different valence‐band X‐ray photoemission features, which are considerably affected by the nanotube diameter distribution and metallic/semiconducting composition.     

五味子科植物中联苯环辛二烯木脂素的碳谱特征

综述了五味子科植物中主要特征成分联苯环辛二烯木脂素类的结构和碳谱特征 .     

In-situ Monitoring of the Porous Silicon Formation by Electrochemical Impedance Techniques and Its Spectroscopic Characteristics

Efficient visible photoluminescence of porous Si is observed on highly porous material, which is currently attributed to quantum confinement effects of the carrier in nanometric sized silicon wires or dots. In this work, the growth of porous silicon layer has been monitored using electrochemical impedance technique.     

J-mixing Effect of the Crystal-field on the Spectroscopic Characteristics of Rare-earth Doped Laser Crystals

1INTRODUCTIONJudd-Ofelttheory""'pointsoutthatthemaincontributiontotheelectricdipole(ED)transitionwithin4fxconfigurationofrare-earthionsinthecrystalarisesfromtheinteractionoftheodd-ordertermsinthestaticordynamiccrystal-field(CF)pcrtential,whichadmixopposite-parityconfigurationsinto4fxconfigurationandhencepermittheEDtransitionwithin4fxconfiguration.InthederivationofJudd-Ofeltformula,itisassumedthatthetotalangularmomentumJ,remainsagoodquantumnumber.However,inthecrystal,theirreducib1erepre…     

Spectroscopic data banks

Computer-equipped spectrometers offer excellent facilities for generation, storage, and manipulation of digitized spectra. The apparent simplicity of using computerized spectroscopic data banks as an aid in structure elucidation of organic compounds has led to vigorous activity in this field. The purpose of this article is to alert potential users, as well as compilers of spectroscopic data banks, to some of the less obvious problems and pitfalls.     

Synthesis and Spectroscopic Studies of Arylethynylsilanes

A variety of arylethynylsilanes (Ar‐C?C? C₆H₄? C?C)_nSiMe_4?n were prepared successfully by reaction of the corresponding chlorosilanes Me_4?nSiCl_n with Ar? C?C? C₆H₄? C?CM (M=Li, MgBr), which was prepared by treatment of ethynyl(diarylethyne)s Ar? C?C? C₆H₄? C?CH with BuLi or MeMgBr. The ethynyl(diarylethyne)s were readily prepared in good yields by the double‐elimination method: addition of lithium hexamethyldisilazide to a mixture of ArCH₂SO₂Ph, TMS? C?C? C₆H₄? CHO, and ClP(O)(OEt)₂, followed by desilylation. In the tetrakis(arylethynyl)silanes (Ar? C?C? C₆H₄? C?C)₄Si thus prepared, through‐space conjugation of four triple bonds on the silicon atom emerges as a result of participation of the silicon orbitals in the acetylenic π orbitals. This participation enhances the emissive quantum yields of arylethynylsilanes with an increase in the number of arylethynyl moieties on silicon: quantum yields of emission (Φ_F) of 0.72 for (MeOC₆H₄? C?C? C₆H₄? C?C)₄Si, 0.53 for (MeOC₆H₄? C?C? C₆H₄? C?C)₂SiMe₂, and 0.47 for MeO‐C₆H₄? C?C? C₆H₄? C?CSiMe₃ were obtained. Although this enhancement effect was also observed in the phenylethynylarylsilane (MeOC₆H₄? C?C? C₆H₄)₂SiMe₂, the bis(arylethynyl)disilane (MeOC₆H₄? C?C? C₆H₄? C?C‐SiMe₂)₂ exhibited non‐enhanced emission.     

Spectroscopic studies on caffeine and isocaffeine

UV and NMR spectra of caffeine and Isocaffeine were measured in three solvents of different polarity. The Information so obtained revealed unique differences in the electronic structure of 7- and 9- alkyl substituted xanthines. 9-Methyl derivatives bear a “soft” nitrogen at position 3; in 7-methylxanthines this nitrogen is rather “hard”. This characteristic distinction is explained on the basis of orbital interactions, which are also responsible for self-association. In the process of self-association. isocaffeine and caffeine share a hydrophobic effect, but in caffeine water bridges play a decisive rote in molecular aggregation. In contrast, in isocaffeine high polarisability makes the most important contribution to self-association. Steric interference between 3- and 9-alkyl substituents or between a 9-methy1 and a 3-NH group, proposed earlier, does not explain satisfactorily the properties of these xanthines.     

红外椭圆偏振光谱及其应用

阐述了红外椭圆偏振光谱的原理，技术的发展，对国外ＳＩＲＥ的应用做了介绍并给出部分实例，共收集文献２９篇。     

Synthesis and Spectroscopic Investigation of Azoporphyrins

Recently the synthesis of the porphyrins and the investigation of their physico-chemical properties have been of increasing interest.In particular,well-designed porphyrin derivatives can act as switches and gates1,nonlinear optics2and other organic photoelectric materials3,4.In these fields the investigation of photoinduced electron transfer is essential in understanding the mechanism and processes of these molecular scale electronic components.Azobenzene and some azobenzene derivatives could …     

Spectroscopic and structural characterization of pascoite

Pascoite mineral having yellow-orange colour of Colorado, USA origin has been characterized by EPR, optical and NIR spectroscopy. The colour dark red-orange to yellow-orange colour of the pascoite indicates that the mineral contain mixed valency of vanadium. The optical spectrum exhibits a number of electronic bands due to presence of VO(II) ions in the mineral. From EPR studies, the parameters of g, A are evaluated and the data confirm that the ion is in distorted octahedron. Optical absorption studies reveal that two sets of VO(II) is in distorted octahedron. The bands in NIR spectra are due to the overtones and combinations of water molecules.