Synthesis of thermochromic formazans of a number of benzazoles

In a search for compounds that have thermochromic properties, a group of formazans that contain benzimidazolyl (benzothiazolyl), methyl (phenyl), and hydroxydinitrophenyl (anthraquinoyl) groups in the 1-, 3-, and 5-positions, respectively, were synthesized. Benzimidazolylformazans with a picramic acid residue in the 5-position have thermochromic properties.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 970–973, July, 1971.     

Short communication: A thermochromism study in the ferrocenyl‐benzopyran series

The synthesis and the photochromic behaviour of a series of benzopyrans (otherwise called 2H‐chromenes), substituted in the 2‐position by a metallocene, have been previously described. Some of these compounds also present thermochromic properties. As the thermochromism has been scarcely studied in the benzopyran series, we describe here a study of the thermochromic properties of ferrocenyl benzopyrans. The correlations between the structure of the compounds investigated and their thermochromic properties are discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

Nonlinear optical absorption properties of two multisubstituted p-dimethylaminophenylethenyl pyridiniums

Two multisubstituted D-pi-A type pyridinium salts, N-methyl-2,6-di[(E)-p-dimethylaminophenylethenyl]pyridinium iodide (1) and N-methyl-2,4,6-tri[(E)-p-dimethylaminophenylethenyl]pyridinium iodide (2), were synthesized with good yields by a modified method, and the structure of 1 was confirmed by X-ray diffraction. The nonlinear optical absorption (NOA) properties of the two compounds in the solution state were investigated by the Z-scan technique. Compounds 1 and 2 both exhibited very strong saturated absorption at picosecond pulse, and 1 displayed reverse saturated absorption, while 2 revealed saturated absorption properties at the nanosecond pulse. The electron-donating ability, number of side chains, and molecular coplanar characteristics of the compounds have a significant impact on their NOA properties.     

可逆热色性化合物的研究进展

本文就可逆热色性化合物的研究现状和发展趋势进行了评述, 着重介绍了可逆热色性化合物的类别、变色原理及应用等。     

Liquid crystal properties of N-alkyl(ethylpyridinium) bromides ω-substituted with a mesogenic group

A new series of ethylpyridinium salts N-substituted with a 4'-methoxybiphenyl-4-yloxyalkyl group has been synthesized and the mesomorphic properties examined. The effect of positioning the ethyl group at each of the three available positions (2; 3- or 4-) on the pyridinium ring was examined and compounds with alkyl chains containing odd numbers of carbon atoms from C5 to C11 were investigated. It was found that the longer chain (C9-C11) 2- and 4-ethylpyridinium compounds form smectic phases, whereas the corresponding 3-substituted compounds do not. X-ray diffraction studies indicated that the smectic phases were of types A, B and in one case E, with the molecules lying in a head to tail fashion in single layers with interdigitated alkyl chains. We explain the difference in mesogenic properties of the three different ring-substituted compounds in terms of packing considerations in the ionic regions of the structures. It is suggested that the 3-derivatives pack more efficiently than the 2- and 4-substituted compounds.     

New 1,3-dithiane type ionic liquid crystal compounds

New pyridinium type thermotropic ionic liquid crystal materials having a 1,3-dithiane ring in their central core, N -substituted-4-(5-alkyl-1,3-dithian-2-yl)pyridinium bromides ( 8 ), were synthesized. These compounds exhibited a smectic A phase over a very wide temperature range including room temperature.     

Preparation of new nitrogen-bridged heterocycles. 49. A new access to thieno[3,4-b]indolizine derivatives

The title compounds, together with 3-vinylindolizine-1-carbonitriles (4-56%), were prepared in 1-18% yields from the S-alkylation of pyridinium 1-[3-ethoxycarbonyl-1-[cyanomethylthio(thiocarbonyl)]]all ylides with alkyl halides, followed by treatment of the resulting pyridinium salts with a base and then a dehydrogenating agent. In several reactions of pyridinium salts obtained from reaction of the allylides with benzylic halides, trace amounts of bis[1-cyano-9-(ethoxycarbonyl)thieno[3,4-b]indolizin-3-yl] disulfides with an interesting superimposed structure were also isolated. The structures of these compounds were confirmed by X-ray analyses.     

Composition and Physicochemical Properties of Cobalt Molybdophosphates

Cobalt molybdophosphates were synthesized. The composition of the compounds was confirmed by IR spectral, thermogravimetric, X-ray phase, and atomic-emission analyses. The influence of the composition on the thermochromic properties of the compounds was demonstrated.     

Research in the benzazole and naphthazole series

The ortho effect of a nitro group in newly synthesized 1-benzothiazolyl-5-(o-nitrophenyl) formazans was investigated. It is shown that these compounds exist in solution as chelates with the participation of the nitro group. The acid-base and thermochromic properties of the formazans were studied.See [1] for communication XXXVII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 774–777, June, 1974.     

“元素化学实验”中的热致变色现象(一)——部分Co(Ⅱ)化合物的热致变色现象及其变色机理探讨

以探讨Co²⁺鉴定实验过程中意外发现在适量CoCl₂溶液中加入适量NH₄SCN溶液的体系具有可逆热致变色现象为切入点,在分析和探讨其热致变色机理的基础上,顺势通过"先做后教、以做定教"实验教学的"翻转课堂"模式,即学生完成元素化学实验,具有亲身经历和切身体会后,以"问题"为导向,以生动直观的演示实验现象为基础,引导学生直观认识一些Co(Ⅱ)化合物的热致变色现象及其影响因素,启发学生应用化学原理与化学知识解释和探讨热致变色现象产生的本质,以加深学生对配合物的结构、性质以及分裂能概念的理解,培养学生的观察、分析、判断、归纳、推理、总结和探索规律的能力以及"批判性"思维能力。     

Synthesis,structure and properties of perimidine spirans

A study was carried out on a new class of photo- and thermochromic spirocyclic cyclohexadienoneperimidines and 4H-naphtholinoneperimidines. The structures of two of these compounds were determined. The lengths of the C_spiro-N bonds were found to be unequivalent; one of these bonds is cleaved in the photo- and thermochromic transformations. The nitrogen atom of the perimidine ring in both compounds was found to have pyramidal configuration with cis arrangement of the unshared electron pairs, while the cyclohexadienone fragments are strongly distorted toward the boat conformation. The nature of the dependence of the photo- and thermochromic properties on their structure and solvent was established.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 702–708, March, 1991.     

New ionic liquid crystal compounds having a 1,3-dithiane or 1,3-dioxane ring

New pyridinium type thermotropic ionic liquid crystal materials having a 1,3-dithiane ring in the central core N-substituted 4-(5-alkyl-1,3-dithian-2-yl)pyridinium bromides and the corresponding 1,3-dioxanes were synthesized and their mesomorphic behaviours compared. The principal feature of these compounds is to exhibit a smectic A phase over a very wide temperature range including room temperature.     

咪唑[1,5-a]吡啶鎓盐的合成、表征及生物活性测定

通过三组份串联反应合成一系列咪唑[1,5-a]吡啶鎓盐,利用1H NMR、13C NMR、MS以及X射线单晶衍射确定其结构,其中以二乙烯三胺与三乙烯四胺为原料获得预期外的结构。以青霉素作为对照,研究了化合物的抗菌性。结果表明,所合成的化合物对溶壁微球菌和乙型链球菌均有抗菌效果,化合物2的抗菌效果最好;含有杂原子O的化合物3对嗜麦芽单胞菌和肺炎克雷伯氏菌的抗菌能力优于青霉素;联苯桥联的刚性双齿咪唑[1,5-a]吡啶鎓(5)比乙基桥联的柔性双齿咪唑[1,5-a]吡啶鎓(4)的抗菌性更强;化合物6为单齿大π体系芳香环,其抗菌效果较好,而化合物7和8为双齿的大π体系芳香环,其抗菌效果较弱。     

二茂铁-噻吩和联噻吩桥连吡啶盐类化合物的合成与电化学性质

设计并合成了3个二取代和三取代的二茂铁-噻吩、二茂铁-联噻吩吡啶盐类化合物： 碘化(E,E)-N-甲基-2,4,6-三{2-[5-(2-二茂铁乙烯基)噻吩-2-基]乙烯基}吡啶盐、 碘化(E,E)-N-甲基-2,6-二{2-[5’-(2-二茂铁乙烯基)-2,2’-联噻吩-5-基]乙烯基}吡啶盐、碘化(E,E)-N-甲基-2,4,6-三{2-[5’-(2-二茂铁乙烯基)-2,2’-联噻吩-5-基]乙烯基}吡啶盐。初步研究了这些化合物的电化学性质,结果表明,该类多取代二茂铁吡啶盐具有很好的氧化-还原可逆性,是潜在的电化学分子材料。     

Palladium-catalyzed direct arylation of pyridine N-oxide with 2-bromoacetanilides. Synthesis of benzisoxazolo[2,3-a]pyridinium tetrafluoroborates

The synthesis of a variety of novel benzisoxazolo[2,3-a]pyridinium tetrafluoroborates is described. These compounds are conveniently prepared from pyridine N-oxide via a microwave-promoted palladium-catalyzed direct arylation of pyridine N-oxide with 2-bromoacetanilides to give 2-(2-acetamidoaryl)pyridine N-oxides, followed by hydrolysis, diazotization and intramolecular displacement of nitrogen which affords the target benzisoxazolo[2,3-a]pyridinium tetrafluoroborates.     

吡啶基团的对称性和离子化对分子双光子吸收截面的影响

采用超快速激光光谱方法研究了含吡啶基团的四个联苯乙烯衍生物及两个杂环分子(A: 4,4’-二(2-(4-吡啶基)乙烯)联苯; B: 4,4’-二(2-(2-吡啶基)乙烯)联苯; C: 1-甲基-4-(2-(4’-(2-(4-吡啶基)乙烯基)-4-联苯)乙烯基)吡啶碘盐; D: 1-甲基-2-(2-(4’-(2-(2-吡啶基)乙烯基)-4-联苯)乙烯基)吡啶碘盐; E: 4-(2-(9-丁基-9氢-3-咔唑)乙烯基)-1-甲基吡啶碘盐; F: 4-(2-(9-丁基-9氢-3-咔唑)乙烯基)-1-甲基喹啉碘盐)的结构-性能关系. 实验结果显示双光子吸收截面最大的是分子E, 高达617.3 GM; 最小的是分子B, 为19.3 GM(1 GM=10^-50 cm⁴·s·photon^-1). 实验研究结果表明, 分子中吡啶基团的对称性及其离子化对分子双光子吸收截面起很重要的作用; 进一步用理论计算证实了以上实验结论并对其机制进行了分析讨论.     

Benzazoles and naphthazoles

1-Benzothiazolyl-5-(p-nitrophenyl)formazans, which have thermochromic properties, were synthesized. The structure of the compounds was studied by means of IR and UV spectroscopy and quantum-mechanical calculations, the state of the tautomeric equilibrium was established, and the most probable planar conformations of the formazans as a function of the character of the substituent in the 3-position of the formazan chain were found. It is shown that the thermochromism of these compounds in solution is related to dissociation of the hydrogen of the NH bond of the formazan grouping and that the deeply-colored thermally induced form is the anionic aci form.     

Preparation of new nitrogen-bridged heterocycles. 56. Syntheses and reactions of 1-[2,2-bis(alkylthio)-1-(ethoxycarbonylacetyl)vinyl]pyridinium salts

The title compounds, readily available from the S-alkylation of pyridinium 1-[alkylthio(thiocarbonyl)](ethoxycarbonylacetyl)methylides with alkyl halides or alkyl bromoacetates, were treated with a base and then a dehydrogenating agent to provide some unique products such as 3-[bis(alkylthio)methylene]-2(3H)-indolizinones and dialkyl 7-methyl-4-oxo-1,4,8,8a-tetrahydro-1,4-thiazino[3,4,5-cd]indolizine-1,5-dicarboxylates. On the other hand, similar reaction of these pyridinium salts in the absence of the dehydrogenating agent afforded alkyl 2-hydroxyindlizine-3-carboxythiolates, whose yields were increased by adding trifluoroacetic acid to the reaction mixture. The structures of some products were confirmed by the X-ray analyses.     

The Synthesis and Reactions of 1-(2-Propynyl)pyidinium Salts

The synthesis of 1-(2-propynyl)pyridinium salts 3 described. Compounds 3 react with a second pyridine molecule, in the presence of the corresponding hydrochloride, to form products of type 4, Certain bases cause the 1-(2-propynyl)pyridinium salts 3 to rearrange into 1-propadienylpyridinium salts. 5 . Diethylamine converts compounds 3 into 1-acetonylpyridinium salts 8 . Moreover, treatment of 3 or 5 with sodium methoxide gives enol ether sof type 9, which can be hydrolyzed to teh ketones 8 . Addition of bromine to some of teh unsaturated compounds is also reported.     

两种新型吡啶盐的合成，表征及双光子性质研究

本文报道了两种新的吡啶盐的合成，用元素分析、红外光谱、单晶X-射线衍射进行了表征。研究了它们的紫外光谱、荧光光谱和光限幅特性，发现它们的DMF溶液对1 064 nm皮秒脉冲激光表现出明显的光限幅特性。