Synthesis and crystal structure of copper complex of 7,16-bis(2-hydroxy-5-methyl-3-nitrobenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane

A lariat crown ether compound 7,16-bis(2-hydroxy-5-methylbenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane has been prepared via one-pot Mannich reaction. A copper(II) complex with the ligand 7,16-bis(2-hydroxy-5-methyl-3-nitrobenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane was unexpectedly synthesized and characterized by elemental analysis, IR and UV spectra. The crystal structure of the complex has been determined by X-ray diffraction. Both crystal structure analysis and spectroscopy study indicated that the side-arm phenols of lariat crown ether are nitrated while complexing with Cu(NO₃)₂. Structure shows that the copper(II) ion is coordinated to two nitrogen and four oxygen atoms, two from the crown ether and other two from the deprotonated phenolate groups. The coordination polyhedron is a distorted octahedron.     

Continuous flow analysis of lead (II) and mercury (II) with substituted diazacrown ionophore membrane electrodes

A novel flow cell for use with ion-selective membrane electrodes is reported in which the carrier stream is drawn through a tube that suppresses the pump noise. PVC membrane electrodes based on 7,16-dithenoyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTODC), and 7,16-di-(2-thiopheneacetyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTAODC) for lead (II), and 7,16-dithenyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTDC) and 7,16-di-(2-methylquinolyl)-1,4,10,13-tertraoxa-7,16-diazacyclootadecane (DQDC), for mercury (II) were prepared and evaluated. The linear ranges were pPb: 5.5-3.0 (DTODC) and 6.0-2.0 (DTAODC); pHg: 5.5-3.0 (DTDC) and 4.5-2.5 (DQDC). With flow rate of 3 ml min(-1) the repeatability of measurements was less than 5% RSD (n = 3). The system was applied to the determination of lead (II) and mercury (II) in spiked natural water samples.     

Synthesis and Crystal Structure of the Copper Complex of 7，16-Bis（2-hyd roxy-5-met hylbenzyl）-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane

A lariat crown ether ligand 7,16-bis (2-hydroxy-5-methylbenzyl)- 1,4,10,13-tetraoxa-7,16-diazacyclooctadeeane (L1) has been prepared via one-pot Mannich reaction. Its copper(Ⅱ) complex Cu-L1 was synthesized and characterized by elemental analysis, IR and UV-visible spectroscopy. The crystal structure of the complex has been determined by X-ray diffraction analysis. The result shows that the copper(Ⅱ) ion is six-coordinated by two nitrogen and four oxygen atoms, two from the crown ether and the other two from the deprotonated phenolate anions, forming an elongated octahedral complex. Electrochemical study indicates that the complex undergoes reversible reduction in DMF solution.     

Lead-selective membrane electrodes based on dithiophenediazacrown ether derivatives

Three double-armed diazacrown ethers with two thiophene side groups, 7,16-dithenyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTDC), 7,16-dithenoyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTODC), and 7,16-di-(2-thiopheneacetyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTAODC), have been synthesized and used as novel neutral lead(II) ionophores in ion selective electrode applications. The relationship between the molecular structure of these ionophores and electrochemical properties (linear range, response time, selectivity) of the membrane electrode is discussed. The optimum conditions for the preparation of the electrodes are described. The optimized dithenoyldiazacrown had a detection limit of pPb = 5.7, and Nernstian range with slope 29.2 mV decade⁻¹ from pPb = 5.0 to 2.7. Mercury and silver ions are the major interferences. These electrodes are applied to potentiometric titrations of lead(II) ions and show promise for the determination of lead ions in water samples.     

双臂套索冠醚双核铜(Ⅱ)配合物的磁性质研究

测定了双臂套索冠醚双核铜(Ⅰ)配合物[Cu₂L(OH)](ClO₄)₃Me₂CO(L=N,N'-二(8-喹啉甲基)-1,4,10,13-四氧-7,16-二氮环八环)的变温磁化率(4～300K),所加场强为5.O×10⁵A/m.拟合了变温磁化率数据,得到J=-279.cm^-1;加上分子场校正后,得J=-257.7cm^-1,Zj'=-30.1cm^-1.拟合结果表明,分子间存在反铁磁性交换作用,而分子内的磁交换(J＜500cm^-1)还未大到使其反铁磁性交换作用变为抗磁性.用自旋倾斜体系解释了其反常的χm-H图.晶体结构和Cu²⁺3d轨道的分析表明,磁交换作用是通过OH桥进行的.比较了另外2个类似的双核铜(Ⅰ)大环OH桥联配合物,得出了J值和轨道重叠之间的关系.     

Mercury macrocyclic complexes: The synthesis of [Hg([18]aneN2S4)] and [Hg(Me2[18]aneN2S4)]. The single crystal x-ray structure of [Hg([18]aneN2S4)](PF6)2·4/3H2O

Reaction of HgSO₄ with one molar equivalent of L{L = [18]aneN₂S₄ (1,4,10,13-tetrathia-7,16-diazacyclooctadecane) or Me₂[18]aneN₂S₄ (7,16-dimethyl-1,4,10,13-tetrathia-7,16-diazacyclooctadecane)} in refluxing MeOH-H₂O for 15 min affords a colourless solution containing the complex cation [Hg(L)]²⁺. Addition of excess PF₆⁻ counterion gives the complex [Hg([18]aneN₂S₄)](PF₆)₂·4/3H₂O as a cream coloured solid. A single crystal X-ray structure determination shows mercury(II) bound to a severely distorted octahedral arrangement of the six macrocyclic donor atoms, Hg---S = 2.655(5), 2.735(4), 2.751(4), 2.639(5) Å, Hg---N = 2.473(11), 2.472(17) Å. The cation is in a rac configuration with the two SCH₂CH₂NCH₂CH₂S linkages bound meridionally to the metal centre.     

Application of tetraoxadiaza-crown ether derivatives as chiral selector modifiers in capillary electrophoresis

Two new diaza-crown ether derivatives (R-1, RS-1) have been synthesized from 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane and tested as potential chiral selectors in capillary electrophoresis (CE) for the chiral separation of five amino acid derivatives. The individual use of the selectors did not lead to chiral differentiation. However, they enhanced the enantioselective effect of different cyclodextrins in dual selector systems. In this paper, we report the effect of different substituted diaza-crown ether derivatives on the separation results obtained in dual systems with cyclodextrins.     

Effect of structural modifications of diaza-18-crown-6 on the extractability and selectivity of univalent metal picrates

The solvent extraction of univalent metal cations with N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16 diaza-2,3,11,12-dibenzocycloocta deca-2,11-diene (L(1)), N,N' didodecyl-1,4,10,13-tetraoxa-7,16-diaza-2,3-benzocylooctadeca-2 ene (L(2)) and N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16 diaza-2,3,11,12-dibenzocyclo octadeca-2,11-diene (L(3)) with picrate anion into dichloromethane has been studied at 25 degrees C by UV-visible spectroscopy. The extractability and selectivity of univalent metal picrates (Li(+), Na(+), Ag(+), PhCH(2)NH(3)(+), NH(4)(+)) was evaluated as a function of [ligand]/[metal cation]. L(2) showed the highest extractability and selectivity for Li(+) over the larger studied cations, and also exhibited the highest [Li(+)]/[NH(4)(+)] selectivity as L/M=1.     

The influence of side-chains on the complexation of cations by crowns. synthesis and cu(ii) complexation of n,n'-diaryl-diaza-18-crown-6

Various N,N'-diaryl derivatives of l,4,10,13-tetraoxa-7,16-diazacyclooctadecane were synthesized. 7,16-diphenyl-l,4,10,13-tetraoxa-7,16-diazacyclooctad On the contrary, diamide derivatives of 7,16-di[(2-amino)phenyl]-l,4,10,13-tetraoxa-7,16- diazacyclooctadecane were deprotonated by Cu(II) and formed stable chelates. Spectral data suggest that monodeprotonation gives dissymmetric 1:1-complexes and dideprotonation gives symmetric 1: 1-complexes.     

Charge-transfer triiodide ion-selective electrode based on 7,16-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane.

A new PVC membrane electrode for the triiodide ion based on a charge-transfer complex of iodine with 7,16-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane as a membrane carrier was prepared. The electrode exhibits a Nernstian response for triiodide ions over a wide concentration range (1.0 x 10(-1)-1.0 x 10(-5) M) with a slope of 59.3 +/- 0.9 mV decade(-1) and a detection limit of 6.3 x 10(-6) M. It has a response time of 30 s and can be used for at least 3 months without any divergence in the potential. The potentiometric response is independent of the pH, in the pH range 1.6 - 10.0. The proposed electrode has shown very high selectivity for the triiodide ion over a wide variety of other anions. This electrode was successfully applied as an indicator electrode in the potentiometric titration of ascorbic acid and hydroquinone from pharmaceutical preparations as well as ascorbic acid in orange juice and dissolved O2 in tap water.     

Syntheses and crystal structures of copper complexes of 7,16-bis (5-t-butyl-2-hydroxybenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane

Reaction of the crown ether ligand H₂L (H₂L=7,16-bis (5-t-butyl-2-hydroxybenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) with Cu(Ac)₂ and Cu(NO₃)₂ affords complexes 1 and 2, respectively, which are characterized by elemental analysis, IR and UV–Visible spectroscopy and X-ray diffraction. Both crystal structure analysis and spectroscopy study unexpectedly showed that the two side-arm p-tert-butylphenols of the original crown ether are converted to nitro p-tert-butylphenols in complex 2. In each complex the copper (II) ion is coordinated to two nitrogen and four oxygen atoms, two from the crown ether ring and other two from the deprotonated phenolate groups, which define an elongated octahedron. Electrochemical studies indicate that the two complexes undergo irreversible reduction in DMF solution.     

Cationic diazacrown ether for the separation of positional isomers by capillary electrophoresis

The use of a positively charged diazacrown ether, N,N,N',N'-tetramethyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane dichloride (1), in capillary electrophoresis is reported, for the first time. The addition of the cationic diazacrown 1 to the running buffer permitted the successful separation of positional isomers of aromatic anions such as naphthalenedisulfonate, naphthalenedicarboxylate and phthalate. At a concentration of 1 of 2 mM, all the analyte anions were completely separated in less than 5 min. The ion association constants of the solute anions with diazacrown 1 were evaluated and the findings are discussed.     

Spectroscopic studies on [(DD18C6H2)(HPA)2](PA)2 and [(DD18C6H2)(DDQ)2](DDQH)2 formed in the reaction of N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane with HPA and DDQ

The interaction of the mixed oxygen-nitrogen cyclic base, N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DD18C6) with pi-acceptors such as picric acid (HPA) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) has been studied spectrophotometrically in chloroform at 25 degrees C. The results obtained indicate the formation of 1:4 charge-transfer complexes with the general formula (DD18C6)(acceptor)4. The electronic and infrared spectra of charge-transfer complexes along with the (1)H NMR spectra were recorded and discussed. Based on the data obtained, the complexes were formulated as [(DD18C6H2)(HPA)2](PA)2 and [(DD18C6H2)(DDQ)2](DDQH)2. A general mechanism explaining the formation of the DDQ complex has been suggested.     

The synthesis of macrocyclic ether-esters,thioether-esters,and ether-thiolesters with the oxalyl moiety

A new series of macrocyclic polyether-diesler compounds ( 3-12 ) have been prepared by treating various oligoethylene glyeols or mercaplans with oxalyl chloride. The compounds prepared were: 1,4,7,10,13-pentaoxacyclopentadecane-2,3-dione ( 3 ), 1,4,7,1 3-tetraoxa-10-thiacyclopenta-decane-2,3-dione ( 4 ), 1,4,10-lrioxa-7,13-dithiacyclopenladecane-2,3-dione ( 5 ), 1,4,7,10,13,16-hexaoxacyclooctadecane-2,3-dione ( 6 ), 1,4,7,10,13, 16-hexaoxacyclooctadecane-2,3,11,12-tetra-one ( 7 ), 1,4,10,13-tetraoxa-7,16-dithiacyclooctadecane-2,3,11,12-tetraone ( 8 ), 7,16-dioxa-1,4, 10,13-letralhiacyclooctadecane-2,3,11,12-tctraone ( 9 ), 1,4,7,10,13,16-hexathiacyclooctadecane-2,3,11,12-tetraone ( 10 ), 1,4,7,10,13,16,19-heptaoxacyclohencicosane-2,3-dione (11), and 1,4,7, 10,13,16,19,22-octaoxacyclolelracosane-2,3,14,15-letraone ( 12 ).     

Electronic, infrared and Raman spectral studies on the molecular complex of N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane with iodine

The molecular complexation reaction between iodine and the interesting mixed oxygen-nitrogen cyclic base N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DBTODAOD) has been studied spectrophotometrically in CH2Cl2, CHCl3, and CCl4. The results of photometric titrations and elemental analysis show that the DBTODAOD base:iodine ratio is 1:4 forming the heptaiodide complex [(DBTODAOD)I]+.I7-. The heptaiodide ion (I7-) is described as I3-(2I2) confirmed by the observation of its characteristic strong absorptions around 365 and 295 nm. In addition, the far infrared spectrum of the solid complex shows the three vibrations of I3- unit at 142, 104, and 62 cm(-1) assigned to nuas(I-I), nus(I-I) and delta(I-3), respectively, while the Raman spectrum shows the corresponding bands at 147 and 108 cm(-1) beside two other bands at 181 and 214 cm(-1) related to the vibration of the I2 unit and the first overtone of nus(I-I) of I3-, respectively. The structure of the formed heptaiodide complex was further supported by thermal gravimetric analysis measurements. Group theoretical analysis indicate that the triiodide unit (I3-) in I7- may be non-linear with C2v symmetry.     

Determination of Binding Selectivities by Electrospray lonization Mass Spectrometry

Electrospray ionization mass spectrometry is used for the measurement of binding selectivities of four model hosts, 18-crown-6, dibenzo-18-crown-6, dicyclohexano-18-crown-6, and 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane, for both alkali and transition metal ions. Based on the intensities of the metal complexes observed in the mass spectra, the relative binding selectivities can be directly estimated. Results are compared to theoretical selectivities obtained by solving simultaneous equilibria equations that define the competing complexation reactions in solution. Good agreement is found in most cases, thus allowing rapid determination of binding selectivities of hosts in a variety of solvents.     

New highly selective picrate sensors based on charge-transfer complexes.

Two novel highly selective potentiometric membrane sensors responsive to picrate ion were developed. They are based on the use of N,N'-dibenzoyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DD18C6)-picrate and Kryptofix 222-picrate charge-transfer complexes as novel electroactive materials in poly(vinyl chloride) matrix membranes plasticized with o-nitrophenyloctylether or dioctylphthalate. The sensors show a Nernstian response with anionic slopes of -59.0 +/- 0.1 and -58.0 +/- 0.2 mV decade(-1) over concentration ranges of 6.0 x 10(-5) - 1.0 x 10(-2) and 7.0 x 10(-5) - 1.0 x 10(-2) mol l(-1) picrate ion and pH ranges of 5-11.5 and 5.5-11.5 for DD18C6 and Kryptofix 222 based picrate sensors, respectively. Both sensors show highly selectivity towards picrate ion over many hydrophilic and lipophilic anions, and exhibit a non-Hofmeister selectivity sequence, which is an improvement over methods reported so far. The sensors are used for the titrimetric determination of alkaloids using picrate as a titrant.     

Three 18-membered macrocyclic diamides with differing donor atoms and backbone substituents

Journal of Inclusion Phenomena and Macrocyclic Chemistry - The crystal structures are reported for 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-6,17-dione, (C12H22N2O6), (I),...     

Chromogenic betaine lariates for highly selective calcium ion sensing in aqueous environment

This paper describes the design, synthesis, and the characterization of the two new chromogenic crown ethers 2,2′-[1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diylbis(methylene)]bis[4-[(1-methyl-4-(1H)-pyridinylidene)ethylidene]-2,5-cyclohexadien-1-one (KBC-001) and the lipophilic derivative 2,2′-[1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diylbis(methylene)]bis[4-[(1-dodecyl-4-(1H)-pyridinylidene)ethylidene]-2,5-cyclohexadien-1-one (KBC-002). A merocyanine dye that forms a betainic structure upon intramolecular charge transfer and shows solvent polarity dependent spectral sensitivity was selected as the chromophore system to develop the new chromoionophores. This approach allows the design of overall electrically neutral ligands bearing charged groups without the need of external counter ions. A proton ionizable group in the dye moiety acts as a charged ion-binding site and is an integral part of a lariat crown ether ionophore. A chromoionophore for calcium ion sensing has been developed, which combines the size-selective binding character of a crown ether with strong electrostatic attraction between the positively charged calcium ion and two negatively charged lariat side arms in the overall neutral compound. This water-soluble dye selectively responds to the presence of calcium ions in water at pH 8.5 with a dynamic response range between 10 μM and 10 mM. The binding event can be monitored both by absorption spectrometry and by fluorescence spectrometry. No cross-sensitivity was found for the physiologically important cations Mg²⁺, Li⁺, Na⁺, and K⁺ up to concentrations of 0.1 M under the same experimental conditions. In contrast to the water-soluble reagent KBC-001, the lipophilized derivative KBC-002 having two long alkyl chains was successfully applied to ion-exchange type optode membranes made from plasticized poly(vinyl chloride) (PVC). The dynamic response range of the optode at pH 9.0 was between 10 μM and 10 mM while retaining the high calcium selectivity.     

Complexation of Macrocyclic Compounds with Nicotinamide in Dimethylsulphoxideand its Water Mixture

The complexation behavior of nicotinamide with macrocyclic polyethers viz, 15-crown-5, benzo-15-crown-5, 18-crown-6, dicyclohexano-18-crown-6, dibenzo-18-crown-6, dibenzo-24-crown-8, 1,4,7,10,13,16-hexathiacyclooctadecane, monoaza-15-crown-5, 1,4,10-trioxa-7,13-diaza-cyclopentadecane, 5,6,14,15-dibenzo-1,4-dioxa-8,12-diazacyclopentadecane, 7,16-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane, 1,4,7-tritosyl-1,4,7-triazacyclononane, 1,4,7,10-tetratosyl-1,4,7,10-tetraazacyclododecane and 1,4,8,11-tetraazacyclooctadecane has been studied in dimethylsulphoxide (DMSO) and 90% DMSO + water using differential pulse polarography and complexation constants have been reported. Nicotinamide forms stable complexes with six-membered coronand rings of the crown ethers. The nature of the atoms (oxygen, sulfur and nitrogen) in the coronand ring is observed to affect the stability of the complex. The stoichiometry and stability constants of the complexes were determined by monitoring the shifts in peak potentials of the polarograms of nicotinamide against the ligand concentration. The Gibbs free energy change turns out to be negative at 25°C, which indicates the spontaneity of the binding of nicotinamide with crown ethers. The mole ratio of nicotinamide to the macrocyclic compound was also determined and it was found that the complexes were of 1:1 type with respect to crown ethers. The tendency of nicotinamide to form complexes with macrocycles is found to be greater in DMSO than in DMSO + water.