- Synthesis and spectroscopic properties of new bis-tetrazoles
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Syntheses of N,N′-phenyltetrazole podands link with aliphatic chains containing oxygen, nitrogen and sulphur atoms, are described. The complexing properties of these compounds towards metal cations (Fe2+, Cu 2+, Zn2+, Co2+, Ni2+) were investigated by absorption and infrared spectroscopy. The UV-Vis titrations were performed to estimate the stability constant values of the respective complexes with Cu2+ ion. Changes in UV-Vis absorption spectra and IR spectra of compound 6 under various concentrations of Cu2+ ion in methanol suggest formation of very unstable complex. The structure of ligand 2 has been deduced by X-ray crystallography. The Author(s) 2012.
- Pazik, Agnieszka,Skwierawska, Anna
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- Fluorescent ion indicators for cadmium and lanthanide ion detection
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The present invention provides a metal chelator and methods that facilitate binding, detecting, monitoring and quantitating of heavy metal ions in a sample. This metal chelating moiety has the following formula
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Page/Page column 37
(2014/01/07)
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- CYCLIC CARBODIIMIDE COMPOUND
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Disclosed is a cyclic carbodiimide compound useful as an end-capping agent for polymer compounds. The cyclic carbodiimide compound is represented by the following formula (i): wherein X is a specific divalent group or tetravalent group, q is 0 when X is a
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Paragraph 0272
(2013/04/10)
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- The halogen-mediated opening of epoxides in the presence of pyridine-containing macrocycles
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The ring opening of epoxides with elemental iodine and bromine in the presence of three pyridine-containing macrocyclic diamides as new catalysts affords vicinal iodo alcohols and bromo alcohols in high yields. This new procedure occurs regioselectively under mild conditions in various aprotic solvents. The catalysts are easily recovered and can be reused several times.
- Sharghi, Hashem,Niknam, Khodabakhsh,Pooyan, Maryam
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p. 6057 - 6064
(2007/10/03)
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- Phenol-containing macrocyclic diamides as new catalysts in the highly regioselective conversion of epoxides to β-hydroxy thiocyanates
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The regioselective ring-opening reactions of some epoxides with ammonium thiocyanate in the presence of a series of new phenol-containing macrocyclic diamides and also dibenzo-18-crown-6-, 18-crown-6-, benzo-15-crown-5-, and pyridine-containing macrocyclic diamide have been studied. The epoxides were subject to cleavage by NH4SCN in the presence of these catalysts under mild reaction conditions in various aprotic solvents. In this study, reagents and conditions have been discovered with which the individual β-hydroxy thiocyanates can be synthesized in high yield and with more than 90% regioselectivity. The results can be discussed in terms of a four-step mechanism: (1) formation of complex between catalyst and NH4SCN, (2) release of SCN- nucleophile from the complex, (3) reaction of the active nucleophile at the less sterically hindered site in the epoxide, and (4) regeneration of catalyst. The major advantages of this method are as follows: (1) high regioselectivity, (2) simple regeneration of catalyst, (3) its reuse through several cycles without a decrease in activity, and (4) ease of workup of the reaction.
- Sharghi,Nasseri,Niknam
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p. 7287 - 7293
(2007/10/03)
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- Synthesis of new dibenzo-diaza-crown ethers
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A new method for the synthesis of dibenzo-diaza-crown ethers involving the 1:1-cyclocondensation of α,ω-contrafunctional amines is reported.
- Gersch, Bernd,Lehn, Jean-Marie,Grell, Ernst
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p. 2213 - 2216
(2007/10/03)
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- CHROMOGENIC CORONANDS. I. C-ARYLCROWN-FORMAZANS OF THE DO-, TRI-, TETRA-, PENTA-, HEXA-, HEPTA-, AND NONANEDECYNE AND DOCOSYNE SERIES
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The 12- to 22-membered dibenzodi(oligo)oxatetraazacoronands containing a crown-ether fragment and an endocyclic C-arylformazan group (C-arylcrown-formazans) in the ring were obtained by template and nontemplate bisazocoupling of bisdiazotized bis(2-aminoa
- Ostrovskaya, V. M.,D'yakonova, I. A.,Poponova, R. V.,Kozlova, N. P.,Ryabokobylko, Yu. S.,Filatova, M. P.
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p. 1583 - 1588
(2007/10/02)
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- Macroheterocycles with an Endocyclic Azo-Group. 1. Tetraazamacrocycles Obtained from Resorcinol
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High-dilution azocoupling of bisdiazotized bis-(2-aminophenyl)oligooxa (or thia)alkanes with resorcinol gives tetraazamacrocycles with two endocyclic azogroups.It is shown that azocoupling occurs exclusively at the 2- and 4-positions of the resorcinol ring.
- Sultanov, A. V.,Savvin, S. B.
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p. 106 - 109
(2007/10/02)
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- SYNTHESIS OF MACROHETEROCYCLES - ANALOGS OF DIBENZO-CROWN COMPOUNDS. 2. 18-MEMBERED DIOXADIAZA-CROWN COMPOUNDS
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Macrocyclic diamides were synthesized by condensation of bridged 1,7-bis(2-aminophenyl)-1,7-dioxaheptanes that contain an additional donor oxygen or nitrogen atom in the bridge with glutaric, diglycolic, and N-tosyliminodiacetic acid dichlorides under hig
- Formanovskii, A. A.,Mikhura, I. V.,Sokolovskii, S. A.,Murakhovskaya, A. S.,Terent'ev, P. B.,Sharbatyan, P. A.
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p. 930 - 936
(2007/10/02)
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- Stereochemistry of Crown Ethers I. Conformational and Dynamic Behaviour of N-Tosyl-Substituted Diaza Crown Ethers
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The variable temperature 1H and 13C NMR spectra of some N-tosyl diaza crown ethers have been obtained.They are discussed with respect to the preferred conformers of the crowns and the free energies of activation of the interconversional process of the large ring.Both the preferred conformers and the ring interconversional barriers have been found strongly dependent on the structure and the ring size of the studied compounds.KEY WORDS Variable-temperature 1H and 13C NMR spectra N-tosyl diaza crown ethers Crown conformation Free energies of activation.
- Kleinpeter, E.,Gaebler, M.,Schroth, W.
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p. 380 - 386
(2007/10/02)
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- Synthesis, N.m.r. Spectra, and Structure of Macrocyclic Compounds containing the Ferrocene Unit
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The condensation of 1,1'-bis(chlorocarbonyl)ferrocene with diaza-18-crown-6 gives 1,1'-(1,4,10,13-tetraoxa-7,16-diazacyclo-octadecane-7,16-diyldicarbonyl)ferrocene (5) together with its dimer 1,1'':1',1'''-bis-(1,4,10,13-tetraoxa-7,16-diazacyclo-octadecane-7,16-diyldicarbonyl)bisferrocene (6) and the separation and isolation of these compounds are described.High resolution 1H and 13C n.m.r. spectra using homo- and hetero-nuclear decoupling techniques allow a complete assignment of the spectral data for (5) and (6) and lead to a proposal of a structure for (5) involving a trans-disposition of the amide carbonyl groups.Variable-temperature n.m.r. data on (6) reveal two distinct dynamic processes within the molecule involving rotation about the ferrocene-carbonyl bond (ΔG=50 kJ mol-1, Tc=-10 deg C) and rotation about the N-CO bond (ΔG=67 kJ mol-1, Tc=+60 deg C).The preparation, 1H and 13C n.m.r. data of monocyclic compounds containing the ferrocene unit (13a-c), (14) and (15) are also described and the details of the synthesis of an 15N-labelled analogue of (13c), the macrocycle (16), are reported.
- Hammond, Philip J.,Bell, Alan P.,Hall, C. Dennis
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p. 707 - 715
(2007/10/02)
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- Short Chain Acyclic Crown Ethers
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A series of short chain acyclic crown ethers such as (1,2), (1,3), (1,4)-phenylenediethers and some symmetric or asymmetric o-substituted phenyl ethers were prepared.The complexation studies of these compounds were carried out by a) direct UV titration me
- Lin, Whei Oh,Souza, Maria Cecilia Bastos Vieira
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p. 253 - 258
(2007/10/02)
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- Ligands for the alkali metals. Part 3. Further examples of nitrogen-containing 'crown' compounds
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An unambigous route from o-aminophenol to dibenzo-crowns with two secondary amine links is reported: Some new mono- and di-nitrogen-containing monobenzo-crowns have also been prepared. The simple mononitrogen-containing crowns can be modified by N-substitution, with, for example, a pendant donor group, sufficiently flexible to co-ordinate to metals held in a polyether ring.
- Lockhart, Joyce C.,Thompson, Maurice E.
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p. 202 - 204
(2007/10/05)
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