飞秒时间分辨取样光谱仪的研制

研制的飞秒（１０＾１５ｓ）时间分辨取样光谱仪由三部分组成；（１）飞秒激光探针弥散补偿光学系统，（２）氩激光泵浦参钛兰宝石飞秒激光系统，（３）信号探测，数据采集分析处理掺钛兰宝石飞秒激光器在７Ｗ氩激光全线泵浦下，能输出平均功率４００ｍＷ、持续期５０ｆｓ到５００ｆｓ的脉冲，其光谱可在７５０ｎｍ到９２０ｎｍ范围内调经ＬＢＯ晶体倍频，能得到３７５ｎｍ到４６０ｎｍ的二次谐波，整体取样光谱仪的时间分辨为９０ｆ     

超快速反应荧光亏蚀谱微观动力学理论

用超短脉冲激发动力学光谱理论在两电子体系下模拟了飞秒时间分辨的荧光亏蚀谱, 再现了实验中所得荧光亏蚀谱的双指数衰减和凹陷两种现象, 这两种现象分别是由于探测脉冲使电子激发态上振动基态和较高振动态的分子受激发射而产生的.     

飞秒光学外差光学克尔效应和低频拉曼光谱技术研究离子液体[bmim][PF6]的低频光谱

利用飞秒光学外差光学克尔效应技术获得了咪唑类离子液体1-丁基-3-甲基咪唑六氟磷酸盐([bmim][PF6])体系中反映分子间相互作用的低频光谱. 结果分析中, 利用Brownian振子时间相关函数的精确表达式对光学克尔效应动力学数据中的核振动部分进行模拟, 在时域上获得各个振动组分的时间演化行为, 并进而通过快速Fourier变换获得各个振动组分的频域光谱和总加和光谱. 此外还利用低频拉曼光谱技术测量了离子液体[bmim][PF6]的低频光谱, 并和飞秒光学外差光学克尔效应实验的结果进行对比, 发现两种方法获得的低频光谱相近. 实验结果表明Brownian振子时间相关函数的精确表达式可用来解析离子液体体系中低频振动的时间演化行为.     

六次甲基四胺与HnXW12O40·mH2O(X=P,Si,Ge)电荷转移盐的合成、表征及非线性光学性质研究

合成了由六次甲基四胺与Ｈ３ＰＷ１２Ｏ４０·ｎＨ２Ｏ,Ｈ４ＳｉＷ１２Ｏ４０·ｎＨ２Ｏ和Ｈ４ＧｅＷ１２Ｏ４０·ｎＨ２Ｏ 形成的具有非线性光学性质的电荷转移盐,并由元素分析,红外光谱,电子光谱进行了表征。结果表明固体中阴阳离子之间存在强的相互作用;非线性光学性质研究表明,三种电荷转移盐的倍频效应分别为ＫＨ２ＰＯ４（ＫＤＰ） 的０ ．１７ ,０ ．２５ 和０ ．０６ 倍;三阶非线性系数分别为６．２ ×１０－ １３ｅｓｕ,８ ．１ ×１０ － １３ｅｓｕ和４ ．３ ×１０ － １３ｅｓｕ。     

比光谱—导数—紫外分光光度法同时测定水中硝酸根和亚硝酸根

利用二元混合物的混合光谱与其中某一组分光谱的比值对波长求导，可达到分辨重叠光谱的目的。本文研究了用比光谱－导数－紫外分光光度法同时测定水样中ＮＯ３＾－和ＮＯ２＾－，以“减法技术”求导，兼具导数光度法能消除低频背景和高频噪声干扰及线性回归法分辨能力强的优点。方法避免了一般光度法需加入试剂而可能引起的误差。在ＰＨ７－９条件下测量２０３ｎｍ－２１９ｎｍ的光吸收值，用比光谱－导数技术处理，同时测定合成度样     

飞秒时间分辨荧光非共线光参量放大光谱技术

时间分辨荧光光谱技术是研究激发态弛豫、能量传递以及电荷转移等光化学过程的重要且直接的工具．飞秒时间分辨荧光非共线光参量放大光谱技术是一种新发展的具有高时间分辨率、宽探测带宽、高增益的时间分辨光谱技术．本文对该技术的基本原理与工作特性、系统配置、荧光收集和会聚、数据采集模式、时问分辨光谱数据处理等进行了系统阐述．最后简单介绍了飞秒时间分辨荧光非共线光参量放大光谱技术在物理、生物和化学领域的3个典型应用,并以此展现该技术的高时间分辨率、宽光谱探测及高增益优势．     

Eu（MBA）2NO3Phen配合物的发光光谱

在７７Ｋ测定了Ｅｕ（ｏ－ＭＢＡ）＿２ＮＯ＿３Ｐｈｅｎ和Ｅｕ（ｍ－ＭＢＡ）＿２ＮＯ＿３Ｐｈｅｎ配合物的激发光谱，发光光谱和时间分辨光谱。光谱数据说明由于邻甲基的位阻影响，在Ｅｕ（ｏ－ＭＢＡ）＿２ＮＯ＿３Ｐｈｅｎ配合物里存在化学环境稍有不同的两种Ｅｕ￣（３＋）格位，它们的局部对称性分别为ｃ＿２ｖ和ｃ＿１，ｃ＿２或ｃ＿ｓ。在Ｅｕ（ｍ－ＭＢＡ）＿２ＮＯ＿３Ｐｈｅｎ配合物里，仅存在一种Ｅｕ￣（３＋）格位，它类似于前一个配合物的ｃ＿２ｖ对称性的Ｅｕ￣（３＋）格位。     

电荷转移器件在原子发射光谱中的应用（Ⅲ）

本文分三部分对国内外原子发射光谱的固态光学多道检测系统特别是电荷转移器件（ＣＴＤｓ）检测器近１０年来的发展进行了综合评价。本篇为其中的第三部分，着重讨论了ＣＴＤｓ－ＡＥＳ系统中光谱信号的采集和处理，光谱诊断，ＣＴＤｓ系统的制冷以及ＣＴＤｓ－ＡＥＳ的主要研究课题。     

角分辨飞行时间法研究紫外激光烧蚀Ta2O5的反应

利用角分辨飞行时间法研究了３５５ｎｍ脉冲激光烧蚀Ｔａ２Ｏ５的反应，由四极质谱测得的煤蚀产物除了Ｏ，Ｔａ，ＴａＯ和ＴａＯ２中性碎片外，在较高激光能量密度时还有Ｏ，Ｔａ，ＴａＯ，ＴａＯ２离子碎片，它们的飞行时间（ＴＯＦ）谱可以用于级分带质心速度的Ｍａｘｗｅｌｌ－Ｂｏｌｚｔｍａｎｎ分布函数较好地拟合，原生离子碎片的平均动能与激光能量密度无关，烧蚀产物原生离子和中性粒子的角分布可以分别用ａｃｏｓ＾ｎθ（ｎ     

偶氮苯聚合物（PAZOS）的合成及其三阶非线性光学特性

合成及表征了一种偶氮苯聚合物聚「３－甲基－４－二（Ｎ，Ｎ－氧亚乙基）氨基－４－硝基偶氮苯癸二酰」通过简并四波混频方法研究了这种聚合物膜的三阶非线性光学性质，测得三三阶非线性光学系数Ｘ＾（３）为６．６＊１０＾－６ｅｓｕ，并考察了其相位共轭光产生特性及光致异构动力学。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.