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1.
N. Zh. Saifullina E. B. Galieva A. K. Tashmukhamedova 《Chemistry of Heterocyclic Compounds》2005,41(9):1183-1185
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.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1388–1390, September, 2005. 相似文献
2.
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. 相似文献
3.
4.
J. A. Kanters F. H. Van Der Steen A. Schouten Pushpa Bagdi N. S. Poonia 《Journal of inclusion phenomena and macrocyclic chemistry》1986,4(3):225-233
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) Å3,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) 相似文献
5.
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. 相似文献
6.
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. 相似文献
7.
Two constitutional isomers of dibenzo-18-crown-6 derivatives (6 and 7) were synthesised and their binding behaviours towards trivalent lanthanoid cations (La3 + , Ce3 + , Pr3 + , Nd3 + , Sm3 + , Eu3 + , Gd3 + and Tb3 + ) were investigated. Both isomers expressed better binding affinities towards Sm3 + and Tb3 + 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 Tb3 + . 相似文献
8.
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. 相似文献
9.
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. 相似文献
10.
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. 相似文献
11.
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. 相似文献
12.
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. 相似文献
13.
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.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 838–840, June, 2006. 相似文献
14.
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+). 相似文献
15.
Zahra Monsef Gholamhossein Rounaghi Ali Sarafraz 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(3-4):321-325
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. 相似文献
16.
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. 相似文献
17.
Reed M. Izatt Tingmin Wang Jon K. Hathaway Xian X. Zhang Janet C. Curtis Jerald S. Bradshaw Cheng Y. Zhu Peter Huszthy 《Journal of inclusion phenomena and macrocyclic chemistry》1994,17(2):157-175
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. 相似文献
18.
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 总被引:1,自引:1,他引:0
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AsⅢ、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。 相似文献
19.
《Analytical letters》2012,45(9):1625-1641
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. 相似文献
20.
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. 相似文献