有机杂化硼酸盐[Ni(dien)_2][B_5O_6(OH)_4]_2的水热合成及晶体结构

硼酸盐不仅结构丰富,而且在矿物学、催化、非线性光学材料、激光材料、隔热隔声材料等方面具有重要的应用, 从而促使人们在研究与探索硼酸盐晶体材料方面作了大量工作,制备出许多性能优良的晶体材料.     

科研成果简介

新型非线性光学晶体低温相偏硼酸钡 近二十年来国外开展了能转换激光波长的非线性光学晶体材料的探索研究。     

有机和金属有机非线性光学晶体材料

非线性光学材料是激光技术的重要物质基础之一,是高技术研究的一个组成部分。二十多年来,非线性光学材料的研究经历了无机晶体、有机材料的阶段,现在又开始了金属有机非线性光学材料的探索。本文拟综述有机和金属有机二阶非线性光学晶体材料的研究进展,而不讨论高分子材料以及三阶非线性光学效应。鉴于刊物读者的特     

红外激光泵浦掺稀土固体材料直接输出蓝绿激光

介绍利用红外或红色激光泵浦掺稀土固体材料直接输出蓝绿激光的途径和研究进展：较为详细地介绍了红外激光泵浦掺稀土非线性激光晶体通过自变频过程，以及红外激光泵浦掺稀土固体块状，光纤和微珠材料通过频率上转换过程实现蓝绿激光输出的研究结果，并与其它输出蓝绿波段激光的器件和方法进行比较，着重对比分析了YAl3(BO3)4,GdAl3(BO3)4,Ca4YO(BO3)3和Ca4GdO(BO3)等典型的非线性激光基质晶体以及氟化物光纤等典型的上转换激光介质材料，对该领域目前面临的主要问题和发展方向进行了探讨。     

LiNbO3：Mg,Er晶体的光谱性质

铌酸锂(LiNbO_3)晶体是优良的电光和非线性光学材料。自从该晶体的光折变损伤被克服以来,MgO与稀土离子双掺LiNbO_3晶体的研究开始活跃起来,并首先在LiNbO_3:Mg,Nd中获得1.093μm和自倍频0.546μm激光输出。Er~(3+)是重要的激活离子,可在十几个通道实现激光输出。作者曾在文献[2]和[3]中首次报道了LiNbO_3,Er晶体生长特性及表面分析的研究结果,本文将介绍该晶体的光谱特性,并讨论LiNbO_3:Mg,Er晶体作为激光材料的可能性。     

硅酸镓镧族非线性光学晶体

中红外非线性光学晶体可以实现中红外激光频率转换、拓展激光波长,在民用和军用领域中有至关重要的应用价值。其中,硅酸镓镧族晶体具有透过范围宽、激光损伤阈值高、晶体质量好等优势,引起了国内外同行的广泛关注。在这篇综述中,我们基于现有的实验数据,研究和分析了三种重要的硅酸镓镧族晶体La_3Ga_5Si O_(14)(LGS)、La_3Ga_(5.5)Nb_(0.5)O_(14)(LGN)、La_3Ga_(5.5)Ta_(0.5)O_(14)(LGT)的综合性能,详细总结了它们在电光调Q开关和中红外光参量振荡以及差频激光输出方面的应用。最后,本文还讨论了今后硅酸镓镧族中红外非线性光学晶体的重点发展方向。     

LiNbO3晶体中Yb3+的配位场能级分析

０引言自从上世纪６０年代LiNbO３晶体合成以来，人们对这种材料的兴趣越来越大。它的优良的非线性特征使LiNbO３晶体成为用于光电装置的最好的物质之一，也是信息贮存和全息照相的很好材料。稀土离子可以很容易地掺杂到该晶体中，用频率自动加倍、自猝灭开关和自动密封等方式来发展微激光。在这种意义上，Yb３＋成为主要的激光材料掺杂离子，它的光谱特征在大量体系中已有研究，已经获得了不同基质中的激光犤１～５犦。由于Yb３＋的谱带积分面积较大，所以，Yb３＋已被用作其它稀土离子的敏化剂，用以提高它们的激发效率，如：Yb－Er…     

聚合物非线性光学材料

最近,有机非线性光学材料已引起了人们极大的兴趣。一些可极化有机分子具有很大的分子超极化率,可惜,受晶体对称性的限制仅有少数晶体具有二阶非线性光学效应。极化聚合物可以产生统计非中心对称的环境,使材料的二阶特性显示出来。本文在简单介绍了有机非线性光学和极化的原理后,综述了聚合物二阶非线性光学材料的研究进展。此外,对聚合物的三阶非线性光学效应的研究也作了介绍。     

稀土激光晶体的发展和现状

稀土激光晶体主要指发光中心为稀土离子的激光晶体材料,这种晶体用专门的单晶炉生长,大尺寸的晶体通常用引上法或坩埚下降法生长,小尺寸的单晶用高温熔盐法生长,长出的优质单晶体经过加工成为适用于激光器的晶体棒或晶体条块,做为激光工作物质,用到相应的激光器件上可以产生激光。稀土离子的激光发射主要是利用能级间的电子跃迁,三价稀土离子主要是4f~N组态内的f-f跃迁,这种跃迁在自由离子状态是禁戒的,在晶体中由奇次晶     

有机非线性光学

由于有机化合物具有非线性光学系数高、响应快等特点,近年来有机非线性光学研究受到了很大的重视。本文从有机非线性光学材料的结构特点出发,综述了典型的四类有机二阶非线性光学晶体方面的研究进展,对三阶材料也作了简要的介绍。     

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.     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

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.