The synthesis and characterization of 22-membered diazapentathia macrocycles and investigation of their ion extraction capability from aqueous media

Two new macrocyclic ligands, (5) and (6), containing nitrogen–sulfur donor atoms were designed and synthesized in a multi-step reaction sequence. Ion extraction capability of macrocycles (5) and (6) were investigated involving solvent extraction of metal picrates such as Ag⁺, Hg²⁺, Cd²⁺, Zn²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Co²⁺ and Pb²⁺ from aqueous phase to the organic phase. The metal picrate extractions were carried out at 25 ± 0.1 °C and extractions were measured by u.v.–visible spectrometry. The extractability and selectivity of the mentioned metal picrates were evaluated depending on the organic solvents used for extraction. The extraction constant (log K_ex) and the complex composition of each metal complex were determined using spectroscopic methods.     

Ion-pair extraction of transition metal cations from aqueous media using novel N2O2-macrocyclic crown ligands

Three new macrocyclic crown ether ligands containing nitrogen–oxygen donor atoms were designed and synthesized from 1,4-bis(2′-formylphenyl)-1,4-dioxabutane and 4-nitro-o-phenylenediamine. Ion-pair extraction of metal picrates such as Ag⁺, Hg²⁺, Cd²⁺, Zn²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Co²⁺, and Pb²⁺ from aqueous phase to the organic phase was carried out using the novel ligands. The solvent effect over the metal picrate extractions was investigated at 25 ± 0.1 °C by using UV–visible spectrometry. The extractability and the values of the extraction constants (log K_ex) were determined for the extracted complexes.     

Synthesis and complexing properties of four imidazolyl acetamido p-tert-butylcalix[4]arenes

Four imidazolyl acetamido p-tert-butylcalix[4]arenes 5–8 have been prepared by reacting the corresponding methyl esters derivatives 1–4 with histamine in 1:1 mixture of methanol:toluene. The yields ranged from 56 to 68%. 5–8 have been shown to be in cone conformation. The complexation behaviour of 5–8 towards monovalent metal picrates M⁺Pic⁻ with M⁺ = Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺ and divalent metal picrates M²⁺(Pic⁻)₂ with M²⁺ = Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Pb²⁺, Cd²⁺, Zn²⁺ and Co²⁺ are given. Tentative localisation of the metal cations in the receptors is given. The binding properties towards these cations have been determined along with stoichiometries of the complexes.     

Synthesis of new macrocyclic lactones and their extraction study

New macrocyclic lactones were synthesized by reaction of 3-bromo-5-(5-tert-butyl-2-hydroxybenzyl)biphenyl-4-ol with appropriate polyethylene glycol-based dicarboxylic acid dichlorides, and their complexes with Mg(ClO₄)₂·6H₂O, Pb(SCN)₂, NaClO₄·H₂O, and KClO₄ were prepared. The macrocyclic ligands were evaluated as extractants in the transfer of Li⁺, Na⁺, K⁺, Cu²⁺, Ni²⁺, and Hg²⁺ picrates from aqueous to organic phase. Published in Russian in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 9, pp. 1400–1405. The text was submitted by the authors in English.     

Transition Metal Ion-binding Properties of a 14-Membered N2O2S2- Macrobicyclic Ligand

The selective liquid–liquid extraction of various transition metal cations from the aqueous phase to the organic phase was carried out using a 14-membered N₂O₂S₂-macrobicycle. Metal picrates such as Pb²⁺, Co²⁺, Zn²⁺, Ni²⁺,Cu²⁺ and Cd²⁺ were used in this extraction studies. It was found that the ligand showed moderate selectivity towards Pb²⁺ only among the other metals. The extraction constant (log K _ex) was determined to be 13.8 for Pb²⁺ complex.     

A new bile acid-derived lariat-ether: Design, synthesis and cation binding properties

A newchola lariat ether (1, a 21-crown-6) was constructed fromreadily available precursors. The association constant of compound1 with alkali metal picrates was measured using Cram’s extraction protocol. Evidence is presented for the involvement of the 3-methoxy group for the complexation. Energy minimised structures show that the A-ring gets slightly distorted upon metal ion binding. Dedicated to Professor C N R Rao on his 70th birthday     

Solvent extraction of univalent and bivalent metal picrates with 1,2-bis[2-(2-methoxyethoxy)ethoxy] benzene (noncyclic crown ether) into CHCl3

The overall extraction equilibrium constants, K_ex, of 1:1:m complexes of 1,2-bis[2-(2-methoxyethoxy)ethoxyjbenzene (AC · B18C6) with uni- and bivalent metal picrates, MA _m were determined at 25°C between CHCl₃ and water, and thereby the ion-pair complex-formation constants,K _MLA,o, of AC · B18C6 with the univalent metal picrates in CHCl₃ were calculated. The AC · B18C6 is an open-chain analog of benzo-18-crown-6 (B18C6). The equilibrium constants of AC · B18C6 were compared with those of B18C6. K_ex sequences of AC · B18C6 for uni- and bivalent metals are Tl⁺ > K⁺ > Rb⁺ > Cs⁺ > Na⁺ > Li⁺ and Pb²⁺ > Ba²⁺ > Sr²⁺, respectively. The same extraction-selectivity was observed for B18C6, but the extractability of AC · B18C6 for the same cation is much lower than that of B18C6; the extraction selectivity of AC · B18C6 for alkali metals is lower than that of B18C6. TheK _MLA,o sequence of AC · B18C6 is K⁺ > Rb⁺ > Tl⁺ > Cs⁺ Na⁺, which is consistent with that of B18C6. ButK _MLA,o of AC · B18C6 is much smaller than the correspondingK _MLA,o of B18C6; the selectivity of AC · B18C6 among alkali metal picrates in CHCl₃ is lower than that of BI8C6. This reflects the difference in the structures between AC · B18C6 (acyclic and flexible) and B18C6 (cyclic and rigid).     

Conductance of substituted amine perchlorates and picrates in N-methyl-2-pyrrolidinone at 25°C

Conductance measurements of 16 perchlorates and picrates of substituted ammonium cations have been made in N-methyl-2-pyrrolidinone (NM-2-Py) at 25°C. To aid in the estimation of ionic conductances, measurements of tetrabutyl-ammonium tetraphenylborate were also included. The data were analyzed by both the full Pitts equation and the expanded Pitts equation in order to obtain limiting molar conductances _o and the ion association constants K _A . The results showed that pyridinium perchlorate and piperidinium, 2,4-dimethyl-pyridinium, 2,4,6-trimethylpyridinium picrates and tetrabutylammonium tetraphenylborate appear to be completely dissociated in NM-2-Py. The values of K _A for the other salts range from 1 to 36 dm³-mol^–1. Limiting molar conductances for the cation were based on the Coplan-Fuoss assumption.On leave 1973–1975 from University of Gdask, Poland.     

Silver selective benzimidazol-2(1H)-one based,sulphur-containing podands

Podands based on benzimidazol-2(1H)-one, containing S and terminal NH₂ groups, selectively transport and extract silver picrate over Mg²⁺, Ca²⁺, Sr²⁺, Ph²⁺ and Tl⁺ picrates.     

Crystal structures of the complexes of rare earth picrates with N, N, N′, N′-tetraphenyl-3, 6-dioxaoctanediamide

The complexes of rare earth picrate with N, N, N′, N′-tetraphenyl-3, 6-dioxaoctanediamide (TDD), [Eu(pic)₃(TDD)]-2CH₃CN and [Y(pic)₃(TDD)], have been synthesized. The crystal structures reveal that TDD acts as a tetradentate ligand, forming a ring-like coordination structure with its oxygen atoms together with one oxygen atom of the bidentate picrate. In the Eu (III) complex, the europium ion with a larger ionic radius lies out of the ring, while in the Y (III) complex, the yttrium ion with a smaller ionic radius enters the cavity of the ligand. The structures of the complexes are greatly affected by the ionic radii due to participation of the picrates in coordination. Project supported by the National Natural Science Foundation of China, the Doctoral Foundation of the State Education Commission of China, and the Climb Plan Foundation of the State Science and Technology Commission of China.     

Structure and fluorescence properties of a europium complex with N-ethyl-2-{2′-[(ethylphenylcarbamoyl) methoxy]-[1,1′]binaphthalenyl-2-yloxy}-N-phenylacetamide

A binaphthylamide complex derived from 1,1′-2,2′-binaphthol (BINOL) and europium picrate has been formed with a wave-like coordination structure through π–π interactions. The molecular structure of [Eu(pic)₃L] (L?=?N-ethyl-2-{2′-[(ethylphenylcarbamoyl)methoxy]-[1,1′]binaphthalenyl-2-yloxy}-N-phenylacetamide; pic?=?picrate) shows that the Eu(III) ion is nine-coordinate with four oxygen atoms from L and five from two bidentate and one unidentate picrates. The structure of the complex was investigated in solution by ¹H NMR, and its fluorescence properties in the solid state and in solution were studied.     

Synthesis, characterization and liquid–liquid extraction properties of new methoxyaminobiphenylglyoxime derivatives and their complexes with some transition metals

In this study, three new aminobiphenylglyoximes, [L¹H₂] N-(2-methoxy)aminobiphenylglyoxime, [L²H₂] N-(3-methoxy)aminobiphenylglyoxime and L[³H₂] N-(4-methoxy)aminobiphenylglyoxime have been synthesized by the reaction of (E,E)-4′-biphenylchloroglyoxime with 2-Methoxyaniline, 3-Methoxyaniline and 4-Methoxyaniline in absolute ethanol. The preparation Ni^II, Co^II and Cu^II complexes of these ligands are described. The ligands and their complexes were characterized by elemental analyses, IR, mass, H¹ and ¹³C NMR spectra, thermogravimetric analyses (t.g.a) and magnetic susceptibility measurements. Ligands complexing properties were studied by the liquid–liquid extraction of selected alkali (Li⁺, Na⁺, K⁺, Cs⁺) and transition metals (Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺). It has been observed that all ligands show a high affinity to Cu²⁺ ions, whereas almost no affinity to alkali metals. The extraction equilibrium constants (K _ex) for complexes of ligands with Cu²⁺ metal picrates between dichloromethane and water have been determined at 25°C.     

A FACIAL SYNTHESIS OF THE NEUTRAL [1,2,4]TRIAZOLO- [3,2-d][1,5]BENZOXAZEPINES AND THEIR CHALCOGEN-ANALOGUES

ABSTRACT

An expedient synthesis of neutral [1,2,4]triazolo[3,2-d][1,5]-benzoxazepines 6a–e and their chalcogen analogues 6f–i was accomplished via cycloaddition of the heterocumulene cations (3a,b), generated sequentially by action of chroman-4-one as well as thiochroman-4-one ethoxy carbonylhydrazones (1a,b) with t-BuOCl and SbCl₅, to the triple bond of nitriles and concurring ring enlargement and hydrolytic removal of the N(1)-ethoxycarbonyl group. The oily final products were characterized as their picrates.     

Equilibrium Study on Ion-Pair Formation in Water and Distribution Between Water and m-Xylene of Tetraalkylammonium Picrates

The 1:1 ion-pair formation constants (K _IP) of tetraalkylammonium (Me₄N⁺, Et₄N⁺, Pr₄N⁺, Bu₄N⁺, and Bu₃MeN⁺) picrates in water were determined by capillary electrophoresis at 25°C. The ion-pair extraction constants (K _ex,ip) of the picrates from water to m-xylene were determined by a batch-extraction method at 25°C, and the distribution constants (K _D) of the neutral ion-pairs were calculated from the relationship K _D = K_ex,ip/K _IP. The tetraalkylammonium ion having more methylene groups generally forms a slightly more stable ion-pair with the picrate ion in water, which is attributed to the lower hydration of the cation. For Me₄N⁺, Et₄N⁺, Pr₄N⁺, and Bu₄N⁺, the distribution of the ion pair into m-xylene increases in that order, and a linear relationship was found between log K _D and the number of methylene groups in the cation. This is consistently explained by the regular solution theory. It was also revealed that the ion pairs have a strong specific interaction with water. The ion pair of Bu₃MeN⁺ has a higher distribution constant than that expected from the relationship between log K _D and the number of methylene groups for the symmetrical tetraalkylammonium ions. The cation dependence of the ion pair extractability is mostly governed by that of the distribution of the ion pair.     

Synthesis and properties of alkyl- and phenyltetrazolium picrates

A series of tetrazolium picrates has been synthesized by quaternization of C- and N-mono substituted tetrazoles using dimethylsulfate and the systemt-BuOH/H₂SO₄ and subsequent precipitation of the cations formed with picric acid. Their thermal stability has been studied using differential scanning calorimetry and thermogravimetric analysis. An x-ray structural investigation has been carried out on 1,3-di-tert-butyl-5-methyltetrazolium picrate.Science Research Institute for Physicochemical Problems, Belorussian State University, Minsk 220080. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 657–665, May, 1998.     

Preparation, crystal structure and luminescent properties of the (6,3) type network supramolecular lanthanide picrate complexes with 2,2′-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide

Solid complexes of lanthanide picrates with a new podand-type ligand, 2,2′-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide (L) have been prepared and characterized by elemental analysis, conductivity measurements, IR and electronic spectroscopies. The crystal and molecular structures of the coordination polymer {[Eu₂L₃(Pic)₆]·(CHCl₃)₃·(H₂O)_0.5}_n have been determined by single-crystal X-ray diffraction, and the structure displays a two-dimensional honeycomb-like framework in the ab plane, which can be regarded as a (6,3) topological network with europium atoms acting as “three-connected” centers. Furthermore, the coordination layers are linked by the intermolecular hydrogen bonds to form a three-dimensional (3-D) netlike supermolecule. Under excitation, Eu complex exhibited characteristic emissions. The lowest triplet state energy level of the ligand indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion.     

Synthesis and Complexing Properties of Four New Tetraamido-type p-tert-Butyl Calix[4]arenes Presenting Two Proximal Binding Subunits

The synthesis of four new tetraamido-type p-tert-butylcalix[4]arenes presenting two proximal binding subunits is reported. Complexation of alkalimetals and zinc picrates with these ligands have been carried out and monitored by ¹H-NMR inCDCl₃. It is shown that hard cations are included in the tetraamido cavity while thezinc cation is chelated to the pyridine rings of one of the ligands. The formation of a 1:1:1heterobinuclear complex is also described     

N-Amino Derivatives of Condensed Imidazole Systems

The previously unknown 1-amino- and 3-aminonaphtho[1,2-d]imidazoles, 1-aminonaphtho[2,3-d]imidazole, 1-aminophenanthro[9,10-d]imidazole and the N-amino-N'-methylimidazolium picrates corresponding to them have been obtained by direct amination of a series of condensed imidazoles with O-picrylhydroxylamine. An X-ray structural investigation of 1-amino-3-methylnaphtho[1,2-d]imidazolium picrate showed that, in difference to 1-aminobenzimidazolium salts, a conformation exists in it in which the hydrogen atoms of the N-NH₂ group are directed to the side of the meso carbon atom.     

Spectroscopic and Crystal Structure of Europium(III) Picrate Complexes with Novel BINOL Derivatives

Two novel ligands N‐Benzyl‐2‐{2′‐[(benzyl‐phenyl‐carbamoyl)‐methoxy]‐[1,1′]binaphthalenyl‐2‐yloxy}‐N‐phenyl‐acetamide (L1) and N‐Methyl‐2‐{2′‐[(methyl‐phenyl‐carbamoyl)‐methoxy]‐[1,1′]binaphthalenyl‐2‐yloxy}‐N‐phenyl‐acetamide (L2), and their europium(III) complexes with picrate, [Eu(pic)₃(L1)] and [Eu(pic)₃(L2)], were synthesized and characterized by elemental analysis, IR, UV‐Vis and fluorescence spectroscopy. The crystal structure of [Eu(pic)₃(L1)]·2CHCl₃ was determined by single crystal X‐ray diffraction. The europium atom is coordinated by nine oxygen atoms of four from the L1 and five from two bidentate and one unidentate picrates. The fluorescent intensity of [Eu(pic)₃(L2)] is about 2.6 times that of [Eu(pic)₃(L1)] in solid states. But in CHCl₃ solution, the fluorescent intensity of [Eu(pic)₃(L1)] is stronger slightly than [Eu(pic)₃(L2)].     

Reactions of 1,1-bis(dimethylamino)-1,3-butadiene with olefins – (4 + 2) cycloadditions and zwitterion formation

1,1-Bis(dimethylamino)-1,3-butadiene ( 1 ) as a strong donor diene (E_1/2 = 0.03 V vs. SCE, 1st IP_v = 6.94 eV) is treated with acrylonitrile, dimethyl dicyanofumarate, and tetracyanoethylene. Cycloaddition with acrylonitrile is slow and requires elevated temperatures at which elimination of dimethylamine with formation of 1-cyano-2-(dimethylamino)-1,3-cyclohexadiene occurs. The reaction of 1 with TCNE at −40°C in acetonitrile is very fast and leads to the zwitterion 5 . At T ⩾ −20°C, 5 eliminates hydrogen cyanide to give a highly colored (λ_max = 489 nm, lgϵ = 4.716) merocyanine. A zwitterion 9 generated from 1 and dimethyl dicyanofumarate can be isolated in crystalline form. The structural analysis shows that the zwitterions are produced by attack of the olefin at the antiperiplanar conformation of 1 . Both zwitterions which can be trapped as crystalline picrates cannot be converted to cycloadducts. These results suggest that cycloaddition is observed if zwitterion formation becomes energetically unfavorable.