功能金属碘酸盐的结构与性能

金属碘酸盐由于含有处于不对称配位环境和孤对电子的碘(V)离子可形成丰富奇特的结构,其中不少化合物是潜在的新型二阶非线性光学材料.它们的透过波段宽、倍频系数大、损伤阈值高而且热稳定性良好.本文总结了金属碘酸盐的结构与性能.将d0过渡金属复合到碘酸盐中可得到很多新颖结构的金属碘酸盐,其抗衡阳离子包括碱金属、碱土金属和稀土元素.由于两种不对称结构单元极化作用的叠加,它们中许多化合物具有非中心对称结构并表现出优良的二阶非线性光学性能.一些稀土碘酸盐在可见或近红外区有很强的荧光.如果碘酸根的孤对电子能排列适当,电子结构为dn(n≠0)的过渡金属与碘酸盐的复合也可得到非中心对称结构的化合物.这些dn过渡金属通常具有八面体或四方平面配位环境.此外两种不同孤对电子阳离子的复合也是设计新倍频材料的一条有效策略.     

碘酸盐的晶体结构与热力学性质——(Ⅱ)碘酸盐的相图、相变及化合规律

本文阐述了碘酸盐及其复盐的熔化特点、形成的相图类型及其化合规律。碘酸盐的固态相变具有多样性和复杂性。结合碘酸盐晶体结构的特点,讨论了碘酸盐所呈现的特异热力学性质与良好的物理性能(电光、压电等),可能是IO_3~-具有未成键电子对所表现的两个侧面。     

碱金属硝酸盐、卤酸盐和高氯酸盐的晶格焓及有关的热力学性质

D.F.C.Morris曾用水合焓循环法计算了碱金属硝酸盐、部分碱金属氯酸盐、个别的碘酸盐和大部分高氯酸盐的晶格能。后来ArthurFinch用同样方法计算了碱金属溴酸盐和碘酸盐的晶格能。由于以上作者所采用的离子对绝对水合焓是以W.M.Latimer等的数据为基础的,计算出来的晶格能无疑会有较大的误差。本文采用作者自己的数据,重新计算碱金属硝酸盐、卤酸盐和高氯酸盐的晶格焓及有关的热力学性质,以期获得较为可靠的结果。     

超分子碱金属膦酸盐——哌嗪双膦酸钠的合成及晶体结构

二维或三维金属膦酸盐聚合物作为功能材料在催化、离子交换和纳米材料等研究领域受到广泛关注 .最初的研究主要集中在四价金属盐 ,后来陆续报道了对于其它价态金属盐的研究 [1～ 3] ,但关于单一碱金属的研究报道较少 . 2 0 0 0年 ,Aranda等[4 ] 报道了首例 Na2 [( HO3PCH2 ) 3NH ]· 1 .5 H2 O( Na PP- 1 )晶体结构 .与其它膦酸盐的明显差别是 ,碱金属双膦酸盐是治疗骨质疏松症的药物 [5] .本文从重要的医药原料哌嗪 [6 ]出发 ,制备并测定了一种具有超分子特征的 α-氨基双膦酸钠Na2 [( HO3PCH2 ) NC4 H8N( CH2 PO3H) ]( H2 O)…     

复盐K2Mg(IO3)4 2H2O的热力学性质

由于碱金属碘酸盐晶体在电学性质的利用上有重要价值和发现碘酸盐晶体非线性性质［‘］，七十年代以来，Vinogradov等对碘酸盐-碘酸-水系统发生了极大的兴趣，做了大量研究工作［’－‘］，发现在碘酸盐．碘酸一水三元体系里有碘酸盐复盐K2M（IO3）4·2H2O（M＝Mn2＋、Co2＋、N     

肉豆蔻酸和棕榈酸酸盐体系的振动光谱研究

报道了肉豆蔻酸和榈酸酸盐体系的振动光谱，结果表明，脂肪酸与其碱金属盐之间通过氢键和羧基配位形成酸盐络合物。酸盐体系中氢键具有不同于普通氢键的性质，本文结合振动光谱讨论了酸盐的结构和氢键性质。     

三硝基均苯三酚及其碱金属盐晶体的周期性密度泛函理论研究

对三硝基均苯三酚(TNPG)及其碱金属盐晶体进行DFT-B3LYP周期性计算研究, 求得其能带和电子结构, 探讨了结构-性能关系. 研究结果表明, 晶胞结构参数的计算值与实验值吻合较好. TNPG的导电性介于半导体和绝缘体之间, 而其碱金属盐均为半导体. 金属离子的引入使TNPG阴离子和金属阳离子通过配位键形成三维无限网状结构, 这种网状结构与晶体的半导体性质相关联. TNPG及其碱金属盐的前线轨道主要是由C—NO₂的原子轨道组成, 配位水和金属离子对前线轨道的组成没有贡献. TNPG碱金属盐的带隙均比TNPG的小, 根据“最易跃迁原理”可推测碱金属盐均比TNPG敏感, 这与实验事实相符. 同时, 金属离子的引入增大了酚羟基上的氧原子的活性, 这也可能是导致碱金属盐比TNPG敏感的原因之一.     

用旋转园盘-园环电极研究碘酸盐阴极还原反应的机理

本文研究了低浓度的碘酸盐在硫酸介质中, 在铂电报上的电化学还原。用旋转盘环电极检测到了碘酸盐阴极还原的中间产物I_2及最终产物I~-。测定了电化学反应的动力学参数。最后提出了磺酸盐阴极反应的机理。     

含二茂铁齐聚苯乙炔分子导线的合成

通过二碘代二茂铁与不同炔化物进行Sonogashira偶联反应,合成了3种新颖的含有二茂铁单元的苯乙炔齐聚物,用1H NMR、13C NMR和MS测试技术分别对其结构进行了表征。 并借助量子化学计算对3种分子的电子结构进行了预测,结果显示,该类型分子导线具有不同于其它类型苯乙炔齐聚物的LUMO能级持续衰减特征,因此极有可能具备极为优良的电子传输性能。     

双(多氟烷氧基磺酰)亚胺碱金属盐的合成、表征及锂盐电解液的性质

制备并表征了双(三氟乙氧基磺酰)亚胺{[N(SO2OCH2CF3)2]-,TFESI-}和双(六氟异丙氧基磺酰)亚胺({N[SO2OCH(CF3)2]2}-,HFPSI-)2个阴离子的10种碱金属盐,并采用示差扫描量热仪(DSC)和热重分析仪(TGA)研究了其相变行为和热稳定性.测试了LiTFESI和LiHFPSI与碳酸乙烯酯(EC)/碳酸甲乙酯(EMC)(3∶7,体积比)组成的电解液的电导率、氧化电位及对铝箔的腐蚀性.结果表明,所制备的碱金属盐均具有较高的纯度和热分解温度(200℃)及较低的熔点(117~211℃);LiTFESI-EC/EMC和LiHFPSIEC/EMC电解液均具有较高的电导率和氧化电位,并对铝箔具有良好的钝化性能,有可能作为锂离子电池的导电盐或添加剂.     

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.     

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.     

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.     

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.     

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.     

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.