Polymorphic behavior and melting points of certain benzocrown ether compounds

Freshly prepared samples of dibenzo-24-crown-8 and 4-t-butylbenzo-15-crown-5 were found to have melting points which varied significantly from those origionally reported in the scientific literature. Samples prepared for the origional report were obtained, and were compared with the new samples. The origional report was found to be in error and the corrected values are provided. Dibenzo-24-crown-8 was found to exist as at least three polymorphs. One of these is a glass. The other two are crystalline, but have identical melting points. It was discovered that the less stable form is thermally converted to the more stable form at temperatures below its melting point.     

含二苯并-18-冠-6席夫碱型液晶冠醚钾配合物的合成与表征

以顺(反)-4,4＇-双[4-(4＇-正烷氧基联苯基-4-羧基) 苯亚氨基] 二苯并-18-冠-6（I和II）为配体合成了2个系列席夫碱型液晶冠醚钾配合物,产率分别为85.5%~92.1%和88.7%~90.7%。配合物的结构通过元素分析、IR、UV-Vis和AAS等方法确证。液晶行为通过DSC、POM、XRD等方法表征。实验结果表明,所有配合物均具有热致液晶性,且随分子末端烷氧基碳原子数增加,其熔点和清亮点呈规律性变化。近晶相温度范围渐增,向列相温度范围递减。与配体相比,配合物液晶态温度范围变宽     

Alkylation of benzo- and dibenzocrown ethers by various alcohols

New alkyl derivatives of benzo-15-crown-5, benzo-18-crown-6, dibenzo-18-crown-6, dibenzo-24-crown-8, and dibenzo-30-crown-10 have been obtained by their alkylation with various alcohols in the presence of polyphosphoric acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1461–1469, November, 1986.     

含X-型二维液晶基元和冠醚环的液晶共聚酯的研究

合成了一系列新的含X-型二维液晶基元和反式-4,4'-双(4-羟基苯基偶氮)二苯并-14-冠-4冠醚环的主链型液晶共聚酯. 通过GPC, [η], DSC, TG, WAXD和POM对其液晶性研究发现, 所有的共聚酯都呈现出向列相的丝状织构或纹影织构. 共聚酯的熔融温度(T_m)和各向同性温度(T_i)随共聚酯分子中反式-4,4'-双(4-羟基苯基偶氮)二苯并-14-冠-4用量的改变呈规律性变化.     

Nitration of Benzo Crown Ethers with Potassium Nitrate in Polyphosphoric Acid

A general method for the nitration of benzo crown ethers with potassium nitrate in polyphosphoric acid has been developed. Mono- and dinitro derivatives of benzo-12-crown-4, benzo-15-crown-5, dibenzo-18-crown-6, and dibenzo-24-crown-8 have been prepared. The role of complex formation in the regioselective tendency for the nitration of dibenzo-18-crown-6 has been demonstrated.     

Acylation of Dibenzo-18-crown-6 with Alkali-metal Acetates in Polyphosphoric Acid

The acylation of dibenzo-18-crown-6 by lithium, sodium, and potassium acetates in polyphosphoric acid was studied. Complexes of dibenzo-18-crown-6 with the acetates were obtained. A new method is proposed for the production of mono- and diacetyldibenzo-18-crown-6 by the reaction of dibenzo-18-crown-6 complexes with metal acetates in polyphosphoric acid. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1146–1149, August, 2005.     

Studies on differential sensing of dopamine at the surface of chemically sensitized ormosil-modified electrodes

We report herein the preparation of few chemically sensitized organically modified sol–gel glass (ormosil) films and sensing of dopamine at the surface of the modified electrodes derived from these films. The chemical sensitization in ormosil-modified electrodes is introduced by incorporating: (a) potassium ferricyanide and (b) either Nafion, or dibenzo-18-crown-6 or in situ generated Prussian blue from potassium ferricyanide. Electrochemical sensing of dopamine on the surfaces of these modified electrodes have been investigated and found that: (i) the presence of dibenzo-18-crown-6 facilitate the magnitude of dopamine sensing, (ii) conversion of potassium ferricyanide into Prussian blue also enhances the magnitude of dopamine sensing as compared to that of control and Nafion sensitized modified electrodes, (iii) both dibenzo-18-crown-6 and Nafion sensitized ormosil-modified electrodes are found selective to dopamine in the presence of ascorbic acid present under physiological concentration range. These finding again directed our attention to investigate the sensing of dopamine: (a) on dibenzo-18-crown-6 incorporated within Prussian blue sensitized modified electrode and (b) in the presence of varying concentrations of dibenzo-18-crown-6 in the Prussian blue modified electrodes. The investigations made on these lines again suggested the following: (1) increase in dibenzo-18-crown-6 concentrations in the modified electrode increases the magnitude of dopamine sensing upto an optimum concentration of macrocycle; (2) the detection limit of dopamine sensing goes down to 30 nM as compared to that of dibenzo-18-crown-6 incorporated with potassium ferricyanide which was found to the order of 100 nM. Investigations of the interference of ascorbic acid revealed that the presence of dibenzo-18-crown-6 introduces selectivity in dopamine sensing in the presence such common interfering analyte like ascorbic acid.     

叔丁基取代二苯并-18-冠-6的合成

以二甘醇和邻苯二酚为原料制得二苯并-18-冠-6;以多聚磷酸为催化剂和溶剂,将二苯并-18-冠-6与叔丁醇反应实现叔丁基化;利用正庚烷重结晶对叔丁基化反应产物进行纯化,得到4,4′-二叔丁基二苯并-18-冠-6和4,5′-二叔丁基二苯并-18-冠-6两种对称的二叔丁基二取代苯并冠醚产品.利用红外光谱和核磁共振谱表征了二叔丁基二取代苯并冠醚产物的结构。     

含二苯并-18-冠-6席夫碱型液晶冠醚钾配合物的液晶行为

以顺(反)-4,4′-双[4-(4′-正烷氧基联苯基-4-羧基)苯亚氨基]二苯并-18-冠-6(Ⅰ和Ⅱ)为配体合成了2种系列席夫碱型液晶冠醚钾配合物,产率分别为85.5%～92.1%和88.7%～90.7%。配合物的结构通过元素分析、IR、UV-Vis和AAS等测试技术确证。液晶行为通过DSC、POM、XRD等方法表征。实验结果表明,所有配合物均具有热致液晶性,且随分子末端烷氧基碳原子数增加,其熔点和清亮点呈规律性变化。近晶相温度范围渐增,向列相温度范围递减。与配体相比,配合物液晶态温度范围变宽。     

New lariat ether carboxylic and hydroxamic acids: Synthesis and lanthanide ion complexation

Twenty-six new lariat ether carboxylic and hydroxamic acids based upon dibenzo-13-crown-4, dibenzo-14-crown-4, dibenzo-16-crown-5 and dibenzo-19-crown-6 ring systems are synthesized and the solid-state structure for a dibenzo-19-crown-6 lariat ether hydroxamic acid is determined. The efficiency and selectivity for lanthanide ion extraction into chloroform by these proton-ionizable lariat ethers is strongly influenced by the crown ether ring size, lipophilic group attachment site and identity of the acidic function. In general, the lariat ether hydroxamic acids were more efficient and selective lanthanide ion extractants than the corresponding lariat ether carboxylic acids. The ¹H nmr and ir binding studies indicate that both the macrocyclic polyether unit and the proton-ionizable group are involved in lanthanide ion complexation.     

Guanidinium-selective PVC membrane electrodes based on crown ethers

Guanidinium-selective membrane electrodes were constructed with dibenzo-24-crown-8, dibenzo-27-crown-9, tribenzo-27-crown-9 or dibenzo-30-crown-10. The detection limits and selectivity coefficients towards different interfering ions, such as Li⁺, Na⁺, K⁺, NH⁺₄, Mg²⁺ and Ca²⁺ were determined. The electrode with dibenzo-27-crown-9 shows linear response over the range 10^?1–10^?4 M, with selectivity coefficients about 10^?2 for most alkali and alkaline earth metal ions.     

Synthesis of new proton-ionizable dibenzocrown ethers

A series of structurally related dibenzo-15-crown-5, dibenzo-18-crown-6, and dibenzo-21-crown-7 compounds with oxymethylacetoxy side arms is synthesized by reaction of the corresponding crown ether alcohols with potassium hydride and bromoacetic acid. Multi-step synthetic routes to the crown ether alcohol precursors are reported.     

含X-型二维液晶基元和顺式-4,4′-双(4-羟基苯基偶氮)二苯并-14-冠-4冠醚环液晶共聚酯的合成与表征

以4,4′-(α,ω-辛二酰氧)二苯甲酰氯(M1)、2,5-二(对十二烷氧基苯甲酰氧基)对苯二酚(M2)和顺式-4,4′-双(4-羟基苯基偶氮)二苯并-14-冠-4(M3)为单体,通过溶液共缩聚反应,合成了一系列含X-型二维液晶基元和顺式-4,4′-双(4-羟基苯基偶氮)二苯并-14-冠-4冠醚环的主链型液晶共聚酯.单体1(M1)由对羟基苯甲酸和辛二酰氯,通过酯化和取代反应制备,单体2(M2)由2,5-二羟基苯醌和对十二烷氧基苯甲酰氯通过酯化和还原反应制备,单体3(M3)由顺式-二氨基二苯并-14-冠-4和苯酚通过重氮化和偶联反应制备.共聚酯的分子量不高,[η]在0·35~0·25dL/g之间.单体的化学结构通过IR、UV、1H-NMR、MS和元素分析等方法确证.共聚酯的外观为黄色粉状固体,除CP9外,室温下不溶于CHCl3和THF溶剂.共聚酯的性质采用GPC、[η]、DSC、TG、WAXD和POM等方法进行了研究.发现所有的共聚酯加热到各自的熔融温度以上都能形成液晶态,在液晶态可以观察到向列相的丝状织构或纹影织构.共聚酯的熔融温度(Tm)和各向同性温度(Ti)随共聚酯分子中顺式-4,4′-双(4-羟基苯基偶氮)二苯并-14-冠-4用量的改变呈规律性变化.WAXD研究进一步证实了共聚酯的液晶性.     

Anomalous behavior of the amides of benzo-and dibenzocrown thiocarboxylic acids under the conditions of methylation

During the reaction of the amides of benzo-and dibenzocrown thiocarboxylic acids with methyl iodide in the presence of potassium hydroxide they exhibit anomalous behavior leading to the nitriles of benzo-and dibenzocrown carboxylic acids. The nitriles of benzo-15-crown-5-, benzo-12-crown-4-, and dibenzo-18-crown-6-4′-carboxylic acids and the dinitriles of dibenzo-18-crown-6-and dibenzo-24-8-4′,4″(5″)-dicarboxylic acids were obtained. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 357–360, March, 2007.     

Transport of alkali and alkaline earth cations by a crown ether-alkylphosphoric acid system

Abstract

Competitive transport of alkali and alkaline earth cations has been carried out by using a mixed carrier system composed of dibenzo-14-crown-4 and bis(2-ethylhexyl)phosphoric acid. In the absence of crown ether, bis(2-ethylhexyl)phosphoric acid transported alkaline earth cations with high selectivity. The combination of dibenzo-14-crown-4 and bis(2-ethylhexyl)phosphoric acid showed a synergistic enhancement in lithium transport, and the enhancement effect was not apparent in transport of other cations. On the other hand, the mixed carrier systems consisting of dibenzo-14-crown-4 and dodecylbenzenesulfonic acid, and of dibenzo-14-crown-4 and 1-bromohexadecanoic acid exhibited the enhancement effects both in lithium transport and in sodium transport. The formation of the synergistic complex was analyzed by using fast atom bombardment mass spectrometry.     

Use of factor analysis and liquid chromatography to determine the number of species in reactions of potassium ions with selected polyethers

Abstract factor analysis is used to determine the number of species in chemical systems from data obtained by high-performance liquid chromatography. Retention data for the systems involving the reaction between potassium ions and three polyethers, benzo-5-crown-5, dibenzo-18-crown-6, and dibenzo-24-crown-8, were obtained in methanol at room temperature. The experimental data were factor-analyzed in order to yield the number of species in the reacting system. In addition to the usual criteria, it is proposed that tree-dimensional graphs of calculated data be compared to three-dimensional graphs of raw data in order to evaluate the factor space. It is also suggested that the three-dimensional graphs showing the residual error matrix be examined as a tool in the evaluation of the factor space. Two species were found from the reaction between benzo-15-crown-5 and potassium, one from dibenzo-18-crown-6-, and there from dibenzo-24-crown-8 in methanol.     

Conductance Study of the Thermodynamics of Binding of Some Macrocyclic Polyethers with Tl+ Ion in Dimethylformamide-Acetonitrile Mixtures

The complexation reactions between Tl⁺ ion and dibenzo-30-crown-10 (DB30C10), dibenzo-24-crown-8 (DB24C8), dibenzo-21-crown-7 (DB21C7), and aza-18-crown-6 (A18C6) were studied in different dimethylformamide-acetonitrile mixtures at various temperatures. The formation constants of the resulting 1 : 1 complexes were determined from the molar conductance-mole ratio data and found to vary in the order A18C6 > DB30C10 > DB21C7 > DB24C8. The enthalpy and entropy of complexation were determined from the temperature dependence of the formation constants.     

Stability of Complexes of NH4 + with 18-Crown-6, Dicyclohexyl-18-Crown-6, Dibenzo-18-Crown-6 and Dibenzo-24-Crown-8 in Water Saturated Nitrobenzene

From extraction experiments with ²²Na tracer, the exchange extraction constants corresponding to the NH₄ ⁺(aq) + NaL⁺ (nb)NH₄L⁺(nb) + Na⁺ (aq) equilibrium taking place in the two-phase water-nitrobenzene system (L = 18-crown-6, dicyclohexyl-18-crown-6, dibenzo-18-crown-6 and dibenzo-24-crown-8; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the NH₄L⁺ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the order dibenzo-24-crown-8 (DB24C8) < dibenzo-18-crown-6 (DB18C6) < dicyclohexyl-18-crown-6 (DCH18C6) < 18-crown-6 (18C6).     

SYNTHESIS OF MAIN CHAIN LIQUID CRYSTALLINE COPOLYESTERS WITH X-SHAPED TWO-DIMENSIONAL MESOGENIC UNIT AND CROWN ETHER CYCLE

A novel series of main chain liquid crystalline copolyesters with X-shaped two-dimensional mesogenic unit and crown ether cycle of cis-4,4′-bis(4-hydroxyphenylazo) dibenzo-18-crown-6 was prepared via solution condensation polymerization from 4,4′-(α,ω-hexanedioyloxy) dibenzoyl dichloride (M1), 2,5-bis(p-octyloxybenzoyloxy) hydro-quinone (M2) and cis-4,4′-bis(4-hydroxyphenylazo) dibenzo-18-crown-6 (M3). Monomer M1 was synthesized by esterification and substitution of adipoyl chloride with p-hydroxybenzoic acid, monomer M2 was synthesized by esterfication and reduction reaction of 2,5-dihydroxybenzoquinone and p-octanoxybenzoyl chloride and monomer M3 was synthesized by diazotization and coupling reaction of cis-diaminodibenzo-18-crown-6 with phenol. The molecular weights of copolyesters are not high,and the intrinsic viscosity [η] of copolyesters ranges from 0.25-0.35. The monomers' structures were identified by using elemental analysis, IR, UV, 1H-NMR, MS, etc. All the copolyesters are yellowish powders and insoluble in THF and CHCl3 at room temperature except CP9. The properties of copolyesters were investigated by using GPC, [η] , DSC, TG,WAXD and POM. It was found that all the copolyesters entered into liquid crystal phase when they were heated to above their melting temperature (Tm). The typical smectic and nematic phase texture can be observed on POM. Their mesophase transition temperature and thermal stability change regularly with varying the content of cis-4,4′-bis(4-hydroxyphenylazo)dibenzo-18-crown-6 unit in the copolyesters.     

含X-型二维液晶基元和反式-4,4′-双(4-羟基苯基偶氮)二苯并-18-冠-6冠醚环的液晶共聚酯的合成与表征

以4,4-′(α,ω己二酰氧)二苯甲酰氯(M1)、2,5-二(对辛氧基苯甲酰氧基)氢醌(M2)和反式4,4′-双(4羟基苯基偶氮)二苯并18冠6(M3)为单体,通过溶液共缩聚反应,合成了一系列含X型二维液晶基元和反式4,4′双(4羟基苯基偶氮)二苯并18冠6冠醚环的主链型液晶共聚酯.共聚酯的分子量不高,[η]在0.37～0.25dL g之间.单体的化学结构通过IR、UV、H NMR、MS和元素分析等方法确证.共聚酯的外观为黄色粉状固体,除CP9外,室温下不溶于CHCl3和THF溶剂.共聚酯的性质采用GPC、[η]、DSC、TG、WAXD和POM等方法进行了研究.发现所有的共聚酯加热到各自的熔融温度以上都能形成液晶态,在液晶态可以观察到近晶相的镶嵌织构或焦锥织构或破扇型织构和向列相的球粒织构或丝状织构或纹影织构.共聚酯的熔融温度(Tm)和各向同性温度(Ti)随共聚酯分子中反式4,4′双(4-羟基苯基偶氮)二苯并18冠6用量的改变呈规律性变化.WAXD研究进一步证实了共聚酯的液晶性.