Synthesis and metal ion complexation of acyclic Schiff base podands with lipophilic amide and ester end groups

A series of acyclic Schiff base podands 14?C19 with lipophilic amide and ester end groups were synthesized in good yield and in a simple way. Their transition metal ions complexation was studied using conductometric method in acetonitrile (AN) at 25 °C. Schiff base podands 14?C16 showed a continuous decrease in the molar conductances in their complexation with Hg²⁺, Pb²⁺, Cu²⁺, Zn²⁺ and Cd²⁺ which begins to level off at a mole ratio of 1:1 crown-to-metal indicating the formation of a stable 1:1 complexes. The order of the stability constants of the metal ions studied with the Schiff base podands 14, 15 and 16 is: Hg²⁺ > Pb²⁺ > Cu²⁺ > Zn²⁺ > Cd²⁺ > Ag⁺. Metal ion complexation by acyclic diamide or diester podands involves presumably the oxygen atoms of the carbonyl groups in addition to the nitrogen atoms of the imino groups.     

New water-soluble calix[4]arene-based bipyridyl podands incorporating carboxylate groups

New calixarene-based bis-bipyridyl podands incorporating two sodium (4-oxo)-butanoate or four sodium carboxymethyl groups at the upper rim were synthesised and fully characterised. The (4-oxo)-butanoate derivative bearing unsubstituted bipyridyl arms was not soluble in water at neutral pH, while its 4,4′-dicarboxylate analogue was perfectly soluble, as were the carboxymethyl derivatives. The association of water solubility to the chelating behaviour of the bipyridyl subunits resulted in the ability to complex the unstable copper(I) cation in water, even in the presence of bovine serum albumin.     

Synthesis and tuberculostatic activity of podands with a dihydropyrimidine fragment

Russian Chemical Bulletin - A method for the preparation of 3-oxobutanoate-containing podands differing in the length of the polyether fragment by acetoacetylation of oligo(ethylene glycols) with...     

Synthesis and properties of polyacetylenes with salicylideneaniline groups

Acetylenes containing salicylideneaniline groups—N‐salicylidene‐3‐ethynylaniline ( 1 ), N‐(3‐t‐butylsalicylidene)‐3‐ethynylaniline ( 2 ), and N‐(3‐t‐butylsalicylidene)‐4‐ethynylaniline ( 3 )—polymerized smoothly and gave yellow to red polymers in excellent yields when a rhodium catalyst was employed. Polymers with alkyl substituents on the aromatic rings [poly( 2 ) and poly( 3 )] were soluble in CHCl₃, tetrahydrofuran, and so forth, whereas the polymer without alkyl substituents [poly( 1 )] was insoluble in any solvent. N‐(3‐t‐Butylsalicylidene)propargylamine did not provide any polymer. Thermogravimetric analyses of the resultant polymers exhibited good thermal stability (T_o, onset temperature of weight loss > 300 °C). The ultraviolet–visible spectra of the polymers showed absorption maxima and cutoff wavelengths around 360 and 520 nm, respectively. The polymers exhibited largely Stokes‐shifted fluorescence (emission wavelength ? 550 nm) upon photoexcitation at 350 nm, which resulted from the photoinduced intramolecular proton transfer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2458–2463, 2002     

Synthesis of podands with nido-carboranyl groups as a basis for construction of crown ethers with an incorporated metallacarborane moiety

The reactions of the dioxane derivative of 7,8-dicarba-nido-undecaborate anion (nido-carborane), [10-O(CH₂CH₂)₂O-nido-7,8-C₂B₉H₁₁], with a series of O,O′-dinucleophiles (pyrocatechol, resorcinol, hydroquinone, and ethylene glycol) were studied. The nido-carborane-based podand was obtained, which can be used for assembling of crown ethers with an inserted metallacarborane moiety.     

Synthesis and properties of polyacetylenes with adamantyl groups

Three disubstituted acetylenes with an adamantyl group—1-(p-adamantylphenyl)-2-chloroacetylene (ClpAdPA), 1-(p-adamantylphenyl)-1-propyne (pAdPP), and 1-(p-adamantylphenyl)-2-phenylacetylene (pAdDPA)—polymerized in good yields in the presence of MoCl₅- or TaCl₅-based catalysts. The highest weight-average molecular weights of poly(ClpAdPA), poly(pAdPP), and poly(pAdDPA) reached 3.6 × 10⁵, 1.1 × 10⁶, and 6.0 × 10⁶, respectively. The polymers were yellow to white solids and completely soluble in toluene, chloroform, and so forth. These polymers thermally were fairly stable, and the onset temperatures of weight loss in air were over 360 °C. Poly(pAdPP) and poly(pAdDPA) provided free-standing films by solution casting, and their oxygen permeability coefficients (P_O2) at 25 °C were 8.6 and 55 barrers [1 barrer = 1 × 10⁻¹⁰ cm³ · (STP) · cm/(cm² · s · cm Hg)], respectively, which are relatively small compared to those of other substituted polyacetylenes. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4546–4553, 1999     

Thermodynamics and selectivity of complexation of lithium and sodium thiocyanates with phosphorus-containing podands and compounds modeling the terminal groups of these podands

A series of model compounds and heptadentate neutral phosphorus-containing podands that differ in the conformational rigidity of the terminal groups and in the coordination properties of the phosphoryl groups were synthesized. The thermodynamic parameters of complexation and the cationic selectivity of organophosphorus compounds and podands with respect to LiNCS and NaNCS were studied by calorimetric titration in acetonitrile at 298 K. The reasons for the high selectivity of certain phosphorus-containing podands to the Li⁺ cation are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1581–1587, September, 1994.This work was financially supported by the Russian Foundation for Basic Research (Grant No. 94-03-08848) and the International Science Foundation (Grant No. MTH000).     

Synthesis and spectral properties of novel seco-porphyrazines with eight 4-biphenyl groups

Magnesium porphyrazinate substituted with eight 4-biphenyl groups on the periphery positions has been synthesized for the first time from cyclotetramerization of 1,2-bis(4-biphenyl)maleonitrile in the presence of magnesium butanolate. Its demetalation by treatment with trifluoroacetic acid, resulted in a partially oxidized product, namely, octakis(4-biphenyl)-2-seco-porphyrazine-2,3-dione. Further reaction of this product with copper(II) acetate, zinc(II) acetate and cobalt(II) acetate has led to the metallo derivatives, [octakis(4-biphenyl)-2-seco-2,3-dioxoporphyrazinato] M(II) (M = Cu, Zn, Co). These novel compounds have been characterized by elemental analysis, together with FT-IR, ¹H NMR, UV–Vis and mass spectral data.     

Synthesis and optical properties of copolymers of 4-aminostyrene with the side styrylquinoline chromophore groups

Successive molecular assembling in polymer chains furnished a series of the comb-shaped copolymers of 4-aminostyrene containing side styrylquinoline chromophore groups. Thermal, thermomechanical, spectroscopic, and luminescent properties of the polymers and low-molecular-weight model chromophores were studied.     

Synthesis, transport and ionophore properties of α,ω-diphosphorylated aza podands: III. Liquid ion-selective electrodes based on phosphorylated aza podands

Aza podands having side α-aminomethylphosphine oxide groups were prepared and used as electrode-active agents in liquid membrane ion-selective electrodes. A series of liqiud membrane electrodes sensitive to Cu²⁺ and Hg²⁺ cations were prepared on the basis of N,N-bis[di(n-hexyl)phosphorylmethyl]piperazine. The electrodes containing copper complexes with aza podands as ionophores exhibit anionic function toward lipophilic anions. Potentiometric and argentometric determination of iodide ions was performed with an iodide-selective electrode based on the mercury complex.     

New 1,2,4-triazine-containing podands: synthesis and properties

A method of one-step C-C coupling of 1,5-bis(2,6-dimethylphenoxy)-3-oxapentane (1a) and 1,8-bis(2,6-dimethylphenoxy)-3,6-dioxaoctane (1b) with 3-methylthio- (2) and 3-amino-1,2,4-triazine (3) and 3-aryl-1,2,4-triazin-5-one (6-8) has been described. The reaction of compounds 1a,b with compounds 2 and 3 in the presence of trifluoroacetic acid results in the addition of the dimethylphenoxy group to the unsubstituted C(5) carbon atom of the triazine ring. The reactions of triazinones 6-8 with compounds 1a,b in a mixture of trifluoroacetic acid and organic anhydrides are accompanied by the acylation of the nitrogen atom adjacent to the reaction center and affords bis[(3-R-1-acyl-5-oxo-1,4,5,6-tetrahydro-1,2,4-triazin-6-yl)-2,6-dimethylphenoxy]-3-oxapentane or -3,6-dioxaoctane. The obtained adducts can smoothly be oxidized under mild conditions to form more stable products of nucleophilic hydrogen substitution in the triazine ring. The extraction and transport of Ca²⁺ and Mg²⁺ cations through an organic membrane by the compounds synthesized are discussed.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2210–2215, October, 2004.     

Synthesis and properties of cyclolinear methylcyclotetrasiloxane polymers with vinyl groups

Atactic cyclolinear organosilicon polymers carrying vinyl groups in RSiO_1.5 or R₂SiO moieties or concurrently in two moieties of the polymer unit have been synthesized by the heterofunctional polycondensation of 2,6-dihydroxymethyl(vinyl)cyclotetrasiloxanes with 2,6-dichloromethyl(vinyl)cyclotetrasiloxanes. The structure of the polymers has been studied by ¹H and ²⁹Si NMR spectroscopy, IR measurements, and elemental analysis. According to DSC, X-ray diffraction, and polarization optical microscopy, the polymers are amorphous in the range from ?100 to +200°C; the interlayer spacing and the type of packing remain unchanged with an increase in the content of vinyl substituents in the repeating units of cyclolinear polymethylvinylsiloxanes.     

Synthesis and properties of novel bifunctional nitrosamines with omega-chloroalkyl groups

Novel N-nitroso-N-(acetoxymethyl)-omega-chloroalkylamines were synthesized and their chemical and biological properties were evaluated. The nitrosamines were expected to decompose through omega-chloroalkyldiazohydroxides in aqueous solution, and then to alkylate various cellular macromolecules. N-Nitroso-N-(acetoxymethyl)-2-chloroethylamine rapidly decomposed in aqueous solution, and the reaction rate was apparently independent of the pH of the solution. On the other hand, the rate of decomposition of chloropropyl and chlorobutyl homologs was pH-dependent, and increased in alkaline solution. When mutagenicity was assayed in Salmonella typhimurium TA1535 and TA92 for preliminary evaluation, all three compounds were directly mutagenic. The mutagenicity in Salmonella typhimurium TA1535, which can detect base-pair change mutation, clearly showed that these compounds induced DNA alkylation in vivo. The increase of alkyl chain length in chloroalkyl compounds increased the mutagenic activity, and the activities were stronger than those of the corresponding simple alpha-acetoxy nitrosamines lacking a chloro group, N-nitroso-N-(acetoxymethyl)alkylamines. Furthermore, the positive result in TA92 suggested that chlorinated nitrosamines cross-linked DNA like antitumor chloroethylnitrosoureas and that they are expected to be new lead compounds for antitumor agents.     

Polyimides with side groups: Synthesis and effects of side groups on their properties

Polyimides are a class of well-known high-performance polymers combined the excellent mechanical, electrical, and thermal properties and widely applied in many high-tech fields. Traditional polyimides can only be processed in the state of soluble intermediates with a hazardous step of cyclodehydration and elimination of a nonvolatile polar solvent. Therefore, a great effort has been devoted to the development of soluble polyimides that can be processed in the full imidation state. The incorporation of side groups into the polyimide backbone is an efficient approach to resolve above problems with a little sacrifice of its inherent merits. The subtle variation of side groups in polyimide backbones has allowed researchers to tune their final properties. In particular, some special side groups can endow polyimides the specific property or functionality to broaden their application fields. In this article, we summarize the synthesis of polyimides with side groups in recent 20 years and further discuss the effect of side groups on their physical and specific properties. The future research directions of polyimides with side groups are also discussed. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 533–559     

Synthesis and spectral properties of 4-amino- and 4-acetylamino-N-arylnaphthalimides containing electron-donating groups in the N-aryl substituent

A method for the synthesis of N-aryl-substituted 4-amino- and 4-acetylaminonaphthalimide derivatives with mono- and dialkoxy groups or a 15-crown-5 moiety in the N-aryl substituent is described. The introduction of electron-donating alkoxy groups into the benzene ring of the N-aryl fragment results in fluorescence quenching of the naphthalimide chromophore, which is most pronounced in the spectra of N-acetyl derivatives. The photophysical properties of the synthesized 4-amino- and 4-acetylaminonaphthalimides depend on the solvent polarity and its specific solvating ability due to H-bonding. The crown-containing compounds are promising fluorescent chemosensors for metal cations.     

Synthesis of podands modified with thiosemicarbazide and fluoroalkyl(hydroxy)pyrazoline fragments

1,8-Bis(diisothiosemicarbazido)-3,6-dioxaoctane have been synthesized by subsequent treatment of 2,2′-(ethylenedioxy)bisethylamine with carbon disulfide, sodium chloroacetate, and hydrazine hydrate. 1,8-Bis- (diisothiosemicarbazido)-3,6-dioxaoctane has reacted with lithium 1,1-difluoropenta-2,4-dionate in glacial acetic acid to yield 1,8-bis[5R*,5′R*(5-hydroxy-5-difluoromethyl-4,5-dihydro-3-methyl-1H-pyrazol-1-yl)-1-carbothioamido]-3,6-dioxaoctane. The molecular and crystal structure of the product has been determined by X-ray diffraction analysis.     

Synthesis and properties of Pluronic-based pentablock copolymers with pendant amino groups

Amphiphilic Pluronic-based pentablock copolymers with pendant amino groups have been successfully synthesized via ring opening polymerization of γ-(carbamic acid benzyl ester)-ε-caprolactone (γCABεCL) and ε-caprolactone (εCL) using Pluronic F127 as macroinitiator and Sn(Oct)₂ as catalyst, and followed by hydrolysis of the Cbz protected groups under acidic conditions. The structure of the copolymer was confirmed by proton nuclear magnetic resonance (¹H NMR) and Fourier transform infrared spectroscopy spectra. In addition, gel permeation chromatography results demonstrated that the synthetic copolymer had a single and symmetrical peak. Moreover, the crystallinity and hydrophilicity could be well adjusted by the content of the functionalized monomer. Successful formation of aggregates was demonstrated by fluorescence method and transmission electron microscopy revealed that the micelles had a spherical morphology and the size was on nano scale according to the laser particle sizer results. The polymeric micelles had no obvious cytotoxicity even the micelles concentration reached 500 mg/L. Thus the Pluronic-b-poly(γ-amino-ε-caprolactone-co-ε-caprolactone) copolymers have great potential for the use in the biomedical fields.     

Synthesis and surface properties of anionic gemini surfactants with amide groups

Novel anionic gemini surfactants, 1,2-bis(N-beta-carboxypropanoyl-N-alkylamino)ethane (2CnenAm; n is hydrocarbon chain length of 6, 8, 10, 12, or 14), with two hydrocarbon chains, two carboxylate groups, and two amide groups, were synthesized by three-step reactions. Their solution properties were characterized by equilibrium and dynamic surface tension, steady-state fluorescence spectroscopy of pyrene, and dynamic light-scattering techniques. The surface tension measurements of 2CnenAm give low critical micelle concentrations (cmc), great efficiency in lowering the surface tension, and strong adsorption at air/water interface. Gemini surfactants behave normally with the logarithm of cmc decrease linearly with the chain length. In addition, adsorption and micellization behavior of 2CnenAm was estimated by parameter of pC20, cmc/C20, and standard free energy (DeltaG(0)mic and DeltaG(0)ads); they are significantly influenced by hydrocarbon chain length, and the adsorption is promoted more than the micellization as chain length becomes longer. The results of dynamic light-scattering and fluorescence quenching indicate that small micelles of 2CnenAm are observed at the concentrations above the cmc, and further large particles are also seen. Further, from the dynamic surface tension measurements, it is found that the shorter hydrocarbon chain length of 2CnenAm, the faster the rate of decrease of surface tension.