有机金属酞菁类化合物及其非线性光限幅特性

随着激光技术的快速发展, 激光武器的性能也越来越优越, 所造成的危害也越来越大, 各国开始加大力度对激光防护材料进行研究. 酞菁化合物具有限幅窗口宽、限幅效果明显、响应迅速等特点, 是一类非常具有应用前景的光限幅材料. 当前, 制备出限幅性能好、稳定性强的酞菁光限幅材料成为激光防护材料领域中的研究热点. 本文评述和总结了近几年在酞菁光限幅材料方面开展的系统研究工作, 首先介绍了酞菁化合物实现光限幅效应的机制, 并在此基础上详细分析了影响光限幅效应的因素以及光限幅器件化过程对酞菁光物理和光限幅性能的影响机理. 根据分析结果提出了在基础和应用研究方面存在的科学问题, 指出了该类型光限幅材料面临的挑战和今后的重要发展方向.     

三苯基咪唑富勒烯吡咯烷衍生物的合成及其紫外、荧光和光限幅性质的研究

通过1,3-偶极环加成合成了四种三苯基咪唑富勒烯吡咯烷衍生物3a～3d,用FT-IR,NMR,MS和元素分析进行其结构测定和表征;用循环伏安法测定了其电化学性质,结果表明,与参比化合物C60相比还原电位发生负移,更容易形成电子受体;用纳秒和飞秒激光研究了四种化合物的光限幅性质,结果表明化合物3a和3c的纳秒光限幅性质明显,而3b则观察不到光限幅现象,说明化合物中硝基的引入不利于光限幅效应.     

螺二芴富勒烯吡咯烷衍生物的合成及电化学和光限幅性能

设计合成了3种新颖的螺二芴键联富勒烯(C₆₀/C₇₀)吡咯烷衍生物, 其结构通过IR, ¹H NMR, ¹³C NMR和MALDI-TOF进行确证, 其电化学性质用循环伏安法进行研究. 结果表明, C₇₀衍生物6的还原电位较C₆₀衍生物7分别向负电势移动0.1, 0.12和0.01 V. 同时, 使用纳秒和飞秒激光分别研究了化合物6, 7和8的光限幅性能, 其光限幅阈值分别为15.3, 23.3和13.7 J/cm², 表明材料具有优异的光限幅性能.     

铟酞菁/聚甲基丙烯酸甲酯复合物固体光限幅器性能

将在溶液中表现出优良非线性光学和光限幅性能的铟酞菁及其二聚物嵌入到非光学活性的聚甲基丙烯酸甲酯(PMMA)中, 用传统的旋转涂膜法制备得到具有较高光学质量的复合物薄膜, 用开孔Z-扫描方法在532 nm 处研究了复合物薄膜材料的线性光学和非线性光学性能. 结果表明, 无论是铟酞菁单体还是轴向氧桥联的铟酞菁二聚物, 其PMMA复合材料的光限幅性能均显著优于相应的酞菁分子在溶液中的光限幅性能.     

金属团簇MoS4Cu4(SCN)2(NC5H5)6的皮秒光学非线性特性和光限幅特性研究

由于激光技术的快速发展，新型超快可调谐波长的高功率激光器更多的在民用和军事上应用。快速的非线性光学器件的需求越来越多。近10年，人们投入大量研究寻找超快光学非线性材料，同时寻找快速响应、高线性透过率和低非线性透过率以及高损伤阈值的光限幅材料，研究发现金属酞菁化合物、金属卟啉化合物以及富勒烯衍生物具有良好的光限幅效果和强的光学非线性特性。     

纳米ZnS在KGM-AE高分子模板中的可控制备与光限幅性能研究

设计了一种新的乙酸酐改性魔芋葡苷聚糖(KGM-AE)作为高分子模板，通过调节模板剂的改性度、模板剂溶液浓度以及Zn²⁺离子浓度，探讨了ZnS纳米粒子形成的机理，制备出了大小及形貌可控的纳米ZnS。利用IR、ICP-AES、XRD、TEM等对ZnS结构进行了表征，并测定了纳米ZnS光限幅性能，结果显示纳米ZnS溶液均呈现出明显的光限幅性能。     

末端基团对芴类衍生物分子非线性光学性质的影响

通过采用预估矫正的时域有限差分方法数值求解速率方程-光场强度方程,研究了纳秒激光脉冲在具有不同末端基团的对称性芴类衍生物分子2,7-双(4′-(二甲基氨基)苯乙烯基)-9-氢-芴(F1分子)和2,7-双(4′-硝基苯乙烯基)-9-氢-芴(F2分子)中的动力学传播过程以及光限幅效应,分析了两种分子的光限幅特性随传播距离(z)、粒子数密度(N)以及脉冲宽度(τ)的变化情况,并且拟合了两种分子的动态双光子吸收(TPA)截面。计算结果表明,该系列分子具有较大的双光子吸收截面以及较好的光限幅效应。此外,F2分子的末端基团―NO2与F1分子的末端基团―N(CH3)2相比具有更强的得电子能力,因而使得F2分子具有更大的跃迁偶极矩,双光子吸收截面增大,光限幅效应更为明显。     

芴酮对聚醚侧链聚芴体系的影响: 合成, 表征及光物理性质的研究

利用Yamamoto聚合反应, 通过调节单体2,7-二溴9,9'-二-(三乙氧基甲基)芴和2,7-二溴芴酮的比例, 合成了侧链为极性聚醚链, 芴酮含量逐渐增加的聚芴系列. 通过聚合物溶液及固态薄膜的紫外荧光谱图, 深入研究芴酮作为能量受体的能量转移过程及其对聚合物光物理性质的影响. 结果表明: 稀溶液中体系呈现聚芴本征态的荧光发射, 能量转移对溶液浓度具有依赖性; 固态薄膜中能量转移效率随芴酮含量的增加而快速增长, 退火后这种现象更加明显.     

二腈基衍生物的合成及其光限幅性质

设计并合成了一系列含不同末端给电子基团及共轭链长度的1,1-二腈基-2,2-二苯基乙烯类化合物(D1-D7),用核磁共振氢谱(1H NMR)、核磁共振碳谱(13C NMR)和高分辨质谱(HRMS)对分子结构进行了表征.选用N,N-二甲基甲酰胺(DMF)为溶剂,测定了它们的线性光物理性质,用光漂白法研究了它们的光稳定性,用热失重法测试了它们的热稳定性.研究了这7个化合物针对800 nm脉冲激光(掺钛蓝宝石激光器,脉冲宽度~130 fs,重复频率1000 Hz)的光限幅性质.结果表明:以二烷基氨基为给电子基团的4个化合物(D4-D7)对800 nm的飞秒脉冲激光均具有显著的光限幅性能,限幅机制为双光子吸收(2PA),而端基给电子能力较弱、共轭链长较短的D1-D3光限幅效果并不明显.此外,D4-D7都具有较好的热稳定性和光稳定性.而且,该系列化合物的双光子吸收截面、光稳定性和热稳定性都具有随分子结构中给电子基团增强或共轭链增长而增大或提高的趋势.D7具有最好的综合性能,是一个有应用潜力的光限幅材料.     

六棱柱型金属团簇化合物W2Ag4S8(dppy)4的纳秒光限幅特性

新合成了一种金属团簇化合物W2Ag4S8(dppy)4,(分子式为C68H56Ag4N4P4S8W2)并用X-射线单晶衍射结构分析方法测定了其晶体结构.单晶X-射线衍射数据表明这种金属团簇化合物具有六棱柱型.在纳秒激光脉冲作用下研究了W2Ag4S8(dppy)4的二甲基甲酰胺(DMF)溶液的光限幅特性.实验结果表明W2Ag4S8(dppy)4的DMF溶液在放置一段时间后光限幅特性明显优于新配制的DMF溶液,其光限幅特性明显强于C60甲苯溶液,表现出其具有较强的光限幅特性.为了研究W2Ag4S8(dppy)4的光限幅机制及光限幅特性在放置一段时间后发生变化的原因,又做了非线性散射和泵浦探测实验,并对其光限幅机制和光限幅特性在放置一段时间后发生变化的原因进行了分析.     

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.     

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.     

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.     

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.     

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.     

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.     

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.