Synthesis of Bis(2,2-benzimidazolyl)dibenzo-18-crown-6

A method has been developed for the introduction of benzimidazole substituents into the dibenzo-18-crown-6 molecule by condensation of its 4′,4″(5″)-diacetyl derivative with ortho-phenylenediamine. Increasing the length of the hydrocarbon chain of the acyl substituent or replacing Ac by CSNH₂ led to a decrease in the yield of the desired product. No product was formed when Ac was replaced by COOH or CN. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1388–1390, September, 2005.     

Hydration of complexes of 18-crown-6 with potassium nitrate or potassium picrate in the polymer phase

Adsorption of water vapor by granular polymer based on dibenzo-18-crown-6 and containing potassium nitrate or potassium picrate in the polymer phase was studied by the isopiestic method at 298 K. The adsorption of water vapor is described by isotherms corresponding (according to BDDT classification) to polymolecular absorption with a high adsorptive potential. In terms of the Aranovich model of polymolecular absorption, the monolayer capacity and differential heat of adsorption were calculated, and the stoichiometry of hydration of the potassium nitrate and potassium picrate complexes with immobilized crown ether was estimated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1940–1942, October, 1998.     

吖啶基功能化二苯并-18-冠-6的合成

通过改变离去基团的活性、亲核试剂、溶剂的极性、离子性及反应温度等,对传统的U llm ann合成法进行了优化,将二苯并-18-冠-6进一步功能化,合成了未见文献报道的N,N′-二-(9-吖啶基)-4,4′-二氨基二苯并-18-冠-6,收率在87%以上。其结构经1H NMR,IR及元素分析表征。     

Synthesis and crystal structure of ammonium (picrate) (dibenzo-18-crown-6)

NH₄(Pic)(DB18C6) (Pic=picrate and DB18C6=dibenzo-18-crown-6), (C₂₆H₃₀N₄O₁₃) FW 606.56, arthorhombic,Pmn2₁,a=26.045(5),b=12.055(3),c=8.982(3) Å,V=2820(1) ų,Z=4,D _c =1.429 g/cm³, CuK, =1.54184 Å, (CuK)=9.5 cm^–1,F(000)=1272,T=298 K. The structure has been refined toR=0.0475 for 2617 unique observed reflections. In the lattice the 1:1 complex exists as a 2:2 dimer in which the crown are coupled through the Pic anions and NH₄ ⁺ cations. The asymmetric unit consists of two independent half crown ethers of which two opposite O atoms are on the mirror plane, two half ammonium cations of which the N and two H atoms are also on the mirror plane while the Pic anion is in a general position. Relative to each other, the corwn ethers are shifted by about 7.3 Å alongb and 1 Å alongc. The 1:1 sandwich of NH₄ with DB18C6 and Pic on dimerisation becomes a club pseudo-sandwich with three phenyl rings on either side of the mirror plane, thus forming a nearly parallel stack with a 3.6 Å inter-ring distance. The NH₄ ions hold the structure; two H atoms on the mirror plane are hydrogen-bonded to the opposite oxygens of the crown located on the purely aliphatic part of the ring (2.10(1), 2.06(3) and 2.26(3), 2.05(1) Å) for the two independent crowns, respectively, while the other two H atoms form mirror-related bifurcated hydrogen bonds with the phenoxide oxygen (1.99(1) and 2.01(1) Å) and theo-nitrogen oxygen (2.44(2) and 2.34(1) Å) of the picrates. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82037 (29 pages)     

Thermodynamics of sorption of KNO3 by a crown-containing polymer

The equilibrium of sorption of KNO₃ from aqueous solutions by a granular polymer containing immobilized dibenzo-18-crown-6 was studied. The thermodynamic characteristics for sorption of an electrolyte by a crown-containing polymer were determined. It was shown that the adsorption sites are energetically equivalent in the range of compositions studied. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 7, pp. 1350–1352, July, 1998.     

Sorption of rubidium chloride by crown-containing polymer

The kinetics and mechanism of the sorption of rubidium chloride from ethanol by granulated polymer containing immobilized dibenzo-18-crown-6 are studied. The sorption of RbCl is controlled by internal diffusion accompanied by complex formation in the polymer. The equilibrium constants of the sorption and diffusion coefficients of the electrolyte in the sorbent are calculated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1025–1028, June, 1995.     

Syntheses of dibenzo-18-crown-6 lariat isomers and their complexation with lanthanoid nitrates

Two constitutional isomers of dibenzo-18-crown-6 derivatives (6 and 7) were synthesised and their binding behaviours towards trivalent lanthanoid cations (La^3 + , Ce^3 + , Pr^3 + , Nd^3 + , Sm^3 + , Eu^3 + , Gd^3 +  and Tb^3 + ) were investigated. Both isomers expressed better binding affinities towards Sm^3 +  and Tb^3 +  than a group of other lanthanoids, as measured by the ligand-to-metal charge-transfer (LMCT) band intensity at ca. 425 nm using UV–vis spectroscopic method. Additionally, the trans isomer 7 was shown to have a higher binding ability than the cis isomer 6 towards Tb^3 + .

     

Sorption of silver and thallium salts by a polymer on dibenzo-18-crown-6

Complexes of 11 composition are formed by sorption of silver and thallium salts from solution by a polymer containing immobilized dibenzo-18-crown-6. The anions are not coordinated. The hydration energy of the anions determines their effect on the transfer coefficients of Ag and Tl from aqueous solutions into the sorbentcontaining crown.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 759–761, April, 1990.     

The kinetics of KNO3 sorption by crown-containing polymer

The kinetics of sorption of KNO₃ from aqueous solutions by a granulated polymer containing fragments of dibenzo-18-crown-6 was studied. Internal diffusion of the electrolyte in the polymer was shown to be a rate-limiting step of sorption of KNO₃. The effective coefficient of diffusion of the electrolyte in the polymer was calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1549–1551, August, 1997.     

Electrosyntheses of free-standing poly(dibenzo-18-crown-6) films in boron trifluoride diethyl etherate on stainless steel electrode

High-quality free-standing poly(dibenzo-18-crown-6) (PDBC) films with a conductivity of 4.1 × 10⁻² S cm⁻¹ and good thermal stability were synthesized electrochemically on stainless steel electrode by direct anodic oxidation of dibenzo-18-crown-6 (DBC) in pure boron trifluoride diethyl etherate (BFEE). In this medium, the oxidation potential onset of DBC was measured to be only 0.98 V vs. SCE, which was much lower than that in acetonitrile + 0.1 mol L⁻¹ Bu₄NBF₄ (1.45 V vs. SCE). PDBC films obtained from this medium showed good redox activity and stability in BFEE. The structural characterization of PDBC was performed using UV-vis, FTIR spectroscopy. The results of quantum chemistry calculations of DBC monomer and FTIR spectroscopy of PDBC films indicated that the polymerization mainly occurred at C₍₄₎ and C₍₅₎ positions). Fluorescent spectral studies indicated that PDBC was a blue light emitter. To the best of our knowledge, this is the first report on the electrodeposition of free-standing PDBC films.     

Sorption of alkali metals and silver nitrates from binary and multicomponent solutions by a crown-containing polymer

The equilibrium in the systems containing a polymer based on dibenzo-18-crown-6 and binary or multicomponent aqueous solutions of NaNO₃, KNO₃, RbNO₃, and AgNO₃ was studied. The constants of the sorption of the individual electrolytes from solution into the polymer were determined. Preliminary calculations of the phase composition on sorption of 11 mixtures of electrolytes with a common anion from the data on the equilibria in the systems with one electrolyte are possible.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 464–466, March, 1993.     

Sulfonation of 4′-acetyl-, 4′-(<Emphasis Type="Italic">tert</Emphasis>-butyl)-dibenzo-18-crown-6 and (dibenzo-18-crown-6)-4′-sulfonic acid with potassium sulfate in polyphosphoric acid

The sulfonation of monosubstituted derivatives of dibenzo-18-crown-6 with potassium sulfate in polyphosphoric acid has been carried out. Sulfonic acids with various functional groups in the second nucleus of dibenzo-18-crown-6 have been obtained. A qualitative comparison of the reactivity of the substrates gave information on the transfer of the electronic influence of a substituent through the macrocycles. The displacement of electron density in the benzene nuclei of the substrates and the products of sulfonation was assessed from the value of the displacement of the proton signals in the ¹H NMR spectra. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 370–375, March, 2009.     

4′,4″(5″)-dibenzo-18-crown-6-diaryl-acetohydroxamic acids

4′,4″(5″)-(Dibenzo-18-crown-6)diarylacetohydroxamic acids were obtained by the reaction of DB18C-6 with β-nitrostyrenes under the influence of polyphosphoric acid. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 838–840, June, 2006.     

Fluorescence sensing of Cu within a pseudo 18-crown-6 cavity

We report herein a pseudo-crown based fluorescent receptor (1) for the selective detection of Cu²⁺ cation. Receptor 1 can detect Cu²⁺ even in 5 μM level in acetonitrile-water (9:1 v/v). Compound 1 is very effective for the detection of Cu²⁺ amongst the series of metal ions studied (Li⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺, Ba²⁺, Pb²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺ and Mn²⁺).     

A Polarographic Study of Tl+, Pb2+ and Cd2+ Complexes with Aza-18-crown-6 and Dibenzopyridino-18-crown-6 in some Binary Mixed Non-aqueous Solvents

The complexation of Tl⁺, Pb²⁺and Cd²⁺ cations by macrocyclic ligands, aza-18-crown-6 (L1) and dibenzopyridino-18-crown-6 (L2) was studied in some binary mixtures of methanol (MeOH), n-propanol (n-PrOH), nitromethane (NM) and acetonitrile (AN) with dimethylformamide (DMF) at 22 °C using DC (direct current) and differential pulse polarographic techniques (DPP). The stoichiometry and stability constants of the complexes were determined by monitoring the shifts in half-waves or peak potentials of the polarographic waves of metal ions against the ligand concentration. In all of the solvent systems, the stability of the resulting 1:1 complexes was found to be L1 > L2. The selectivity order of the L2 ligand for the cations was found to be Pb²⁺ > Tl⁺ > Cd²⁺ and the selectivity of the L1 ligand for Pb²⁺ ion was greater than that of Tl⁺ ion. The results show that the stability of the complexes depends on the nature and composition of the mixed solvents. There is an inverse relationship between the stability constants of the complexes and the amount of dimethylformamide in the mixed solvent systems.     

Solid-solid synthesis of a hydrophobic vitamin B12 having a benzo-18-crown-6 moiety at the C10 position of the corrin ring

A new hydrophobic vitamin B₁₂ having a benzo-18-crown-6 moiety at the C-10 position of the corrin ring was synthesized by solid-state condensation reaction. The proton NMR titration study in acetonitrile exhibits a potassium ion binding behavior of the hydrophobic vitamin B₁₂ at the benzo-18-crown-6 moiety.     

Factors influencing enantiomeric recognition of primary alkylammonium salts by pyridino-18-crown-6 type ligands

Equilibrium constant (K), enthalpy change (H), and entropy change (S) values were determined for the interactions of a series of chiral pyridino-18-crown-6 type ligands with enantiomers of several primary alkylammonium salts in various solvents. Good enantiomeric recognition in terms of logK was observed in many systems with logK values greater than 0.4. The extent of enantiomeric recognition and the stabilities of the chiral crown ether-ammonium salt complexes were found to depend on the rigidity of the macrocyclic frame of the ligand, the type and arrangement of the donor atoms on the ligand, the bulkiness of the substituents on the ligand's chiral centers, the location of the chiral centers on the ligand, and the solvent. The effects of these factors on the extent of enantiomeric recognition and on the stabilities of the complexes were examined for the systems studied.     

基于2，3-萘-18-冠-6单元的共轭高分子对金属离子的荧光传感器

能发射蓝绿色荧光的共轭高分子由单体1,4-二溴-2,3-萘-18-冠-6(M-2)与1,4-二乙烯基-2,5-二丁氧基苯(M-3)通过Pd催化的Heck偶联反应合成制得。通过荧光和紫外-可见光谱探讨了高分子对金属离子的响应性质,其中Hg²⁺能使高分子荧光淬灭、吸收增强,但As^Ⅲ、Pb²⁺和K⁺对高分子的荧光光谱改变很小。结果表明以2,3-萘-18-冠-6作为荧光团和识别位点的共轭高分子可作为有效识别Hg²⁺的荧光化学传感器。     

Solvent Extraction Studies of Metal-4-(2-pyridyl-azo)-Resorcinol Complexes with Potassium-Dicyclohexyl-18-crown-6 Complex

Abstract

The solvent extraction studies of Pd(II), V(V), Co(III), Cu(II), Ni(II) and Fe(II)-PAR [4 - (2-pyridyl azo)-resorcinol] complexes with dicyclohexyl-18-crown-6 have been investigated in 1,2-dichloroethane as a solvent. It was observed that the complexes of Pd(II), V(V), Co(III), Cu(II), Ni(II) and Fe(II)-PAR were extracted into organic phase. In order to investigate the effect of enthalpy and entropy in the extraction of metal-PAR complexes, an attempt has been made to explore the temperature effect. In the extraction studies, it was observed that the entropy effect is one of the major factors for the selective extraction. The shape of the complexes may be one of the causes for the extractability of metal-PAR complexes with potassium dicyclohexyl-18-crown-6. The planar palladium-PAR-SCN^? complex was easily extracted into organic phase in comparison with other complexes.     

Thermal decomposition of cobalt nitrato compounds: Preparation of anhydrous cobalt(II)nitrate and its characterisation by Infrared and Raman spectra

The thermal decomposition of Co(NO₃)₂·6H₂O (1) as well as that one of NO[Co(NO₃)₃] (Co(NO₃)₂·N₂O₄) (2) was followed by thermogravimetric (TG) measurements, X-ray recording and Raman and IR spectra. The stepwise decomposition reactions of 1 and 2 leading to anhydrous cobalt(II)nitrate (3) were established. In N₂ atmosphere, cobalt oxides are finally formed whereas in H₂/N₂ (10% H₂) cobalt metal is produced. Rapid heating of cobalt(II)nitrate hexahydrate causes melting (formation of a hydrate melt) and therefore side reactions in the hydrate melt by incoupled reactions and evolution/evaporation of different species as, e.g., HNO₃, NO₂, etc. In case of larger amounts in dense packing in the sample container, the formation of oxo(hydoxo)nitrates is possible at higher temperature. For 2, its thermal decomposition to 3 was followed and its decomposition mechanism is proposed.