质子化4,4’-联吡啶盐与二苯并-24-冠-8的包合行为

通过1H NMR, ESI-MS, 紫外-可见光谱等分析手段研究了两个新的质子化联吡啶盐客体与冠醚二苯并-24-冠-8在溶液中和气态下的包合行为. 研究结果表明, 质子化的联吡啶盐与冠醚主要形成1∶1的超分子包合物, 且存在夹心式的几何结构, 双质子化的联吡啶盐比单质子化的联吡啶盐具有更强的结合冠醚的能力, 其缔合常数分别为200, 116 L•mol－1.     

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.     

A Mixed Phase C60 + Dibenzo-24-crown-8 for Gas Chromatography

Stationary phases for gas chromatography were prepared: 10 wt % fullerene C₆₀ on Inerton N-AW (deposition from saturated toluene solution) and a mixed phase C₆₀ + dibenzo-24-crown-8. These phases were tested in a wide temperature range (40-280°C) with selected organic compounds containing various functional groups and with their mixtures.     

Crystal Structures of Dibenzo-13-crown-4 and sym-(2-Picolyloxy)dibenzo-13-crown-4

Solid-state structures are determined for two compounds which containdibenzo-13-crown-4 rings. These include the parent crown etherdibenzo-13-crown-4 and its lariat ether derivativesym-(2-picolyloxy)dibenzo-13-crown-4. The solid-state structure ofdibenzo-13-crown-4 is complicated by disorder of the carbon atoms in theethylene and propylene bridges. The asymmetric unit of the crystal for thelariat ether derivative consists of two chemically identical, butcrystallographically different, molecules.     

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).     

Solid-state structures of sym-dibenzo-16-crown-5 and its derivatives

Solid-state structures of sym-dibenzo-16-crown-5 (1) and five derivatives with one or two substituents on the three-carbon bridge have been determined. The derivatives with three sp³-hybridized carbons include sym-(propyl)dibenzo-16-crown-5 (4), sym-(pentafluorophenoxy)-dibenzo-16-crown-5 (5), and sym-[di(methoxymethyl)]dibenzo-16-crown-5 (6). Structures of two derivatives with sp²-hybridization of the central carbon (7 and 8) were also determined. Twisting of the three-carbon bridge causes one of the terminal methylene groups to be oriented within the polyether cavity.     

Modification of salsoline, salsolidine, and anabasine with dibenzo-24-crown-8-dicarboxylic acid dichloride

New derivatives of dibenzo-24-crown-8-dicarboxylic acid diamide with salsoline, salsolidine, and anabasine moieties were prepared by condensation of the alkaloids with 4′,4″(5″)-dibenzo-24-crown-8-dicarboxylic acid dichloride. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 471–473, September–October, 2006.     

Preparation of chloromethyl derivatives of dibenzo-18-crown-6 and syntheses based on them

The reaction of chloromethylated dibenzo-18-crown-6 and some monosubstituted derivatives (4-acetyl-, 4-propionyl-, and 4-tert-butyldibenzo-18-crown-6) was studied. Modification of the chloromethyl group resulted in the synthesis of various dibenzo-18-crown-6 derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 470–474, April, 1989.     

Synthesis of Phenacyl Esters by Using PTC and Dibenzo-[18]-crown-6

In view of the importance of phenacyl esters as a protecting groups, a simple and efficient method is now reported here for synthesis of phenacyl esters in quantitative yield and high purity under mild reaction condition by using phase transfer catalyst and dibenzo-[18]-crown-6. It has been demonstrated that the spatial coordination of ion and ligand cavity plays important role in using crown ethers.     

二苯并-18-冠-6与杯环芳烃毛细管气相色谱混合固定相的协同效应研究

在气相色谱混合固定相中 ,一直认为具有加和效应 .但近年来我们 [1,2 ] 在研究特殊选择性气相色谱混合固定相时 ,在填充柱气相色谱中发现了协同效应 ,并在气相色谱领域运用协同效应概念( Synergistic Effect) ,而后又在毛细管气相色谱中观察到这种现象 [3,4 ] .由于冠醚有一个洞穴的结构 ,并存在氢键作用 ,因此对很多极性的位置异构体的分离具有高选择性 [5] .杯芳烃也是一个具有洞穴式结构的特殊分子 ,它能与一些金属离子和有机分子形成包合物 ,已被用于分离位置异构体 [6 ] .本文将二苯并 - 1 8-冠 - 6与杯环芳烃的衍生物组成混合固定相 …     

Potentiometric Selectivities of Dibenzo-16-crown-5 Compounds for Alkali and Alkaline Earth Metal Cations and Ammonium Ions

Potentiometric selectivities toward alkali and alkaline earth metal cations and ammonium ions are utilized to probe the complexation of these cationic species by dibenzo-16-crown-5 lariat ethers. Attachment of one or two pendant groups to the central carbon of the three-carbon bridge in dibenzo-16-crown-5 markedly alters the potentiometric responses of the ionophores when incorporated in solvent polymeric membrane electrodes. Results obtained for dibenzo-16-crown-5 compounds with coordinating side arms containing ether, carboxylic acid, ester, and amide groups provide insight into the role of the side arm in metal ion complexation by lariat ether compounds.     

New Derivatives of Dibenzo-18-crown-6 with Salsolidine and Salsoline Fragments

New derivatives of dibenzo-18-crown-6 were prepared by condensing 4,4(5)-dibenzo-18-crown-6-dicarboxylic acid dichloride with salsolidine and salsoline. The structures of these compounds were proved by PMR and IR spectral methods.     

微波辅助二苯并-18-冠-6的合成

以邻苯二酚与二甘醇二取代物为原料,氢氧化钾为碱和模板剂,在微波辅助下,采用“一锅煮”法合成二苯并-18-冠-6。 经单因素及正交实验考察了原料、溶剂、时间、温度和功率对反应收率的影响,获得了最佳的工艺条件：以邻苯二酚与二氯乙醚为原料,二甲亚砜为溶剂,反应温度70 ℃,时间60 min,功率500 W,收率可达46.3%。     

Inclusion of a Cu2+ ion by a large-cavity crown ether dibenzo-24-crown-8 through supramolecular interactions

A supramolecular copper-aqua-crown ether complex, [Cu(II)(H2O)4(dibenzo-24-crown-8]2+ (1c) is stabilized with a Lindqvist-type polyoxometalate anion, [Mo(VI)6O19]2- (1a), in an ion-pair compound [Cu(II)(H2O)4(dibenzo-24-crown-8][Mo(VI6O19] identical with [1c][1a] identical with 1. In the crystal, 1c and 1a assemble to a chainlike structure in which each polyoxoanion 1a is sandwiched by two 1c cations. 1c is a structurally characterized dibenzo-24-crown-8 (a larger-cavity crown ether) supramolecular complex that shows encapsulation of a small cation at the center of its internal cavity, and compound 1 represents a unique example of a first-row transition metal-crown ether inclusion complex that interacts with a polyoxometalate anion.     

Two protocols for the preparation of [2]rotaxanes based on the dibenzo-24-crown-8-based cryptand/paraquat recognition motif

Host–guest complexation between a dibenzo-24-crown-8-based cryptand and a paraquat derivative was studied. Subsequently, two novel [2]rotaxanes based on the dibenzo-24-crown-8-based cryptand/paraquat recognition motif were prepared by threading-followed-by-stoppering method and single-pot method, respectively. The obtained mechanically interlocked structures were confirmed by ¹H NMR, ¹³C NMR, 2D NMR, and ESI-MS.     

Stabilities in Water of Alkali Metal Ion Complexes with Dibenzo-24-crown-8 and Dibenzo-18-crown-6 and Their Transfer Activity Coefficients from Water to Nonaqueous Solvents

Stability constants K _ML for the 1:1 complexes of Na⁺, K⁺, Rb⁺, and Cs⁺ with dibenzo-24-crown-8 (DB24C8) and dibenzo-18-crown-6 (DB18C6) in water have been determined by a capillary electrophoretic technique at 25°C. The K _ML sequence is Na⁺ < K⁺ < Rb⁺ < Cs⁺ for DB24C8 and Na⁺ < K⁺ > Rb⁺ > Cs⁺ for DB18C6. Compared with DB18C6, DB24C8 exhibits higher selectivity for K⁺ over Na⁺, but lower selectivity for K⁺, Rb⁺, and Cs⁺. To evaluate the solvation of the complexes in water, their transfer activity coefficients sH₂O between polar nonaqueous solvents and water have been calculated. The sH₂O values provide the following information: interactions with water of the metal ions and of the crown-ether oxygens are greatly reduced upon complexation and the complexes undergo hydrophobic hydration in water; the character of each alkali metal ion in solvation is more effectively masked by DB24C8 than by DB18C6, because of the larger and more flexible ring structure of DB24C8. Solvent effects on the complex stabilities are discussed on the basis of the sH₂O values.     

Unraveling the molecular recognition of "three methylene spacer" bis(benzimidazolium) moiety by dibenzo-24-crown-8: pseudorotaxanes under study

"Three methylene spacer" bis(benzimidazolium) derivatives act as a new template for threading dibenzo-24-crown-8 into [2]pseudorotaxanes. In this Article we sought to unveil the difference in the extent of threading of various "three methylene spacer" bis-benzimidazolium moieties based on differences in aromatic methyl substituent positions and anions through the macrocycle dibenzo-24-crown-8. The temperature of the systems were also varied (low temperatures of 240 K and 253 K), when such interwinding of the thread and crown were not detected at room temperature of 308 K. The presence of such threaded complexes was determined based on (1)H-NMR initially and finally corroborated by high resolution mass spectrometry and DFT calculations. 2D-NMR experiments ((1)H-(1)H-NOESY) proved to be a very important tool in elucidating the interaction present between the components of the pseudorotaxanes. The dethreading/rethreading process was studied. DFT optimized structures suggest lower energy H-bonding orientations and compare the effect of methyl substituents on the axle.     

The Role of Potassium Cation in the Favorskii Ethynylation of Acetone: Effekt of Dibenzo-18-crown-6

Macrocyclic polyether dibenzo-18-crown-6 possessing a specific affinity for potassium cation inhibits ethynylation of acetone with acetylene in the presence of KOH according to Favorskii. The inhibition becomes stronger in the presence of the complex dibenzo-18-crown-6 ? KOH ? MeOH as catalyst (both in excess acetone and in DMSO). The effect does not originate from deactivation of acetone, for its aldol-like condensation is accelerated in the presence of both dibenzo-18-crown-6 and its complex (the selectivity of ethynylation sharply falls down). Thus, apart from the high basicity of the medium, activation of acetylene due to complex formation with potassium cation plays an important role in the Favorskii ethynylation of ketones.     

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.     

冠醚共缩聚物的合成与性能

双冠醚化合物对某些金属离子比单冠醚具有更好的络合性能和选择性,它们合成、应用研究越来越受到人们的重视,本工作采用2,6-二羟甲基对甲氧基苯酚为缩合剂与芳香族冠醚缩聚,得到一系列具有双冠醚结构特征的新酚醛型聚苯并冠醚(简称聚冠醚),聚冠醚合成容易,并呈现了比相应单冠醚更优越的络合萃取能力和富集效率。