41775-36-4Relevant academic research and scientific papers
A Chromogenic Reagent for Calcium. The Importance of Ion-pairing in Cation Selection
Mason, Andrew,Sutherland, Ian O.
, p. 1131 - 1132 (1994)
The chromoionophore 2 has been synthesized from the corresponding diaza 18-crown-6 in two steps in good overall yield, and the reagent 2 extracts calcium cations from aqueous solutions in the pH range 7-9 with moderately high selectivity as compared with
Synthesis, NMR studies and crystal structure of cryptand 4,7,10,16,21-pentaoxa-1,13-diazabicyclo[11.5.5]tricosane, [H(3.1.1) ·(H2O)3]Cl
Nguyen, Tam,Buckley, Christopher M.,Ellis, Trevor K.,Smith, Gary L. N.,Powell, Douglas R.,Taylor, Richard W.
, p. 573 - 577 (2012)
The cryptand 4,7,10,16,21-pentaoxa-1,13-diazabicyclo[ 11.5.5]tricosane (3.1.1, I) has been synthesized, the crystal structure of the triaquo-hydrochloride salt has been determined by single crystal X-ray crystallography and the 1H- and 13C-NMRchemical shifts have been assigned for the protonated ligand. [(C16H 33N2O5)·(H2O) 3]Cl, (I), is triclinic with space group P1 and cell constants: a = 9.957(3) A, b = 10.557(5) A, c = 11.324(3) A, α = 95.917(8)°, β = 105.574(8)°, γ = 107.506(9)°, V = 1071.4(3) A3 and Z = 2. In the solid state the cryptand is monoprotonated and holds a water molecule near the central cavity using the hydrogen bonds N13-H13 to O1S, O1S-H1S2 to N1 and O1S-H1S1 to ether oxygen atom O7. Pairs of cryptand molecules are linked by a hydrogen bond network, (O21· · ·H2S2-O2S-H2S1· · ·Cl1) 2(μ-H3S1-O3S-H3S2)2, that interacts with an ether oxygen (O21, O21A) in each ligand molecule. Springer Science+Business Media, LLC 2012.
Macrocyclic Ligands with an Unprecedented Size-Selectivity Pattern for the Lanthanide Ions
Hu, Aohan,MacMillan, Samantha N.,Wilson, Justin J.
supporting information, p. 13500 - 13506 (2020/09/09)
Lanthanides (Ln3+) are critical materials used for many important applications, often in the form of coordination compounds. Tuning the thermodynamic stability of these compounds is a general concern, which is not readily achieved due to the similar coord
Steric and stereoelectronic effects in aza crown ether complexes
Solov'ev, Vitally P.,Strakhova, Nadezhda N.,Kazachenko, Vladimir P.,Solotnov, Alexandr F.,Baulin, Vladimir E.,Raevsky, Oleg A.,Ruediger, Volker,Eblinger, Frank,Schneider, Hans-Joerg
, p. 1379 - 1389 (2007/10/03)
Stability constants and enthalpy changes determined by calorimetric titrations and supported by selected NMR titrations are reported for the complexation of sodium and potassium cations with 18 different crown ethers containing nitrogen atoms with different number, location and substitution pattern. The data, measured in methanol mostly with potassium salts, are compared to literature data; they show striking differences between all-oxygen analogs and the macrocycles with NH groups. In contrast, affinities with aza crown ethers bearing alkyl groups at the nitrogen as well as with the cryptand [2.2.2] come closer to the complexation free energies predicted from the number and electron donating capacity of the ligand heteroatoms. This is rationalised on the basis of molecular mechanics calculations, showing that a NH-containing crown predominates in conformations with axial N lone pairs, due to their repulsive electrostatic interactions with the ring oxygen atoms. Replacement of the hydrogen by alkyl groups forces the lone pairs to an equatorial position, thus enabling better complex formation, as borne out by experiment. In line with these arguments the IgK differences are with some exceptions more due to ΔH than to TΔS differences. The calorimetric data show linear isoequilibrium correlations between TΔS and ΔH, with slopes between those observed with other crown ether and cryptand complexes. Preliminary investigations of some synthetic macrocyclic amide precursors yield appreciable complexation only, if the two carbonyl oxygens can come in close contact with the guest cation. Computer aided molecular modelling shows that this is possible in a small 15C5-derivative, in which the polyethylenglycol cycle only serves as ring template without binding contributions from the ether oxygen atoms.
An Improved One-Step Method to Prepare Diaza-crown Ethers and the Cation Complexation Properties of 4,10-Diaza-18-Crown-6 with Two Transition Metal Ions
Krakowiak, Krzysztof E.,Maas, Garren E.,Bradshaw, Jerald S.,Hathaway, Jon K.,Izatt, Reed M.
, p. 179 - 182 (2007/10/02)
4,10-Diaza-15-crown-5, 4,10-diaza-18-crown-6, 4,13-diaza-21-crown-7, and 4,16-diaza-24-crown-8 were prepared by an improved method from the appropriate oligothylene glycol diiodides and diamines.The thermodynamic values of log K, ΔH and ΔS for the interaction of 4,10-diaza-18-crown-6 with Pb2+ and Ag+ were determined by a calorimetric titration method and compared with thermodynamic values for interactions of 4,13-diaza-18-crown-6 with the same cations.The thermodynamic values were found to be different for the two diaza-crown ligands. 4,10-Diaza-18-crown-6 and its 4,13-diaza-crown analog formed precipitates when treated with Co2+, Cd2+, Cu2+, and Ni2+ so that no thermodynamic data are reported for these interactions.
MACROHETEROCYCES. XXXVI. A CONVENIENT METHOD FOR SYNTHESIS OF DI- AND POLYAZACROWN ETHERS
Luk'yanenko, N.G.,Basok, S.S.,Filonova, L.K.
, p. 1562 - 1571 (2007/10/02)
A method is proposed for the production of di- and polyazacrown ethers by the condensation of bissulfonamides with dibromides or ditosyloxy derivatives in a two-phase aqueous alkali-toluene (benzene) system.The optimum concentration range for the substrate and the alkylating agent is 0.017-0.1 M.The catalytic activity of the quaternary ammonium salts decreases in the order (Bu)4NI > (Bu4)NBr > (Bu4)NCl > (Bu4)NHSO4 > (C2H5)3C6H5CH2NCl >> (Et)4NI > (Et)4NBr.The highest yields of te 12-membered azacrown ethers are obtained in the presence of lithium hyroxide, and the largest yields of the crown ethers with larger ring sizes are obtained in the presence of sodium or potassium hydroxide, and this is probably due to the matrix effects of the cation.
MACROHETEROCYCLES. PART 44. FACILE SYNTHESIS OF AZACROWN ETHERS AND CRYPTANDS IN A TWO-PHASE SYSTEM
Lukyanenko, Nikolai G.,Basok, Stepan S.,Filonova, Lyubov K.
, p. 3141 - 3148 (2007/10/02)
A facile procedure is proposed for the preparation of azacrown ethers and cryptands by condensation of dibromides or ethylene glycol bis(toluene-p-sulphonate)s with acyclic bis(sulphonamide)s or with bisdiazacrown ethers, respectively.The reaction was carried out in a two-phase system of aqueous alkali-toluene (benzene)in the presence of quaternary ammonium salts as phase transfer catalysts.The catalytic activity decreased in the sequence: Bu4NI ca.Bu4NBr > Bu4NCl > Bu4NHSO4 > Et3NCH2C6H5NCl.Maximum yields of twelve-membered azacrown ethers are obtained when lithium hydroxide is used, while crown ethers of larger size are observed in the presence of sodium or potassium hydroxides; this may be due to a template effect.
MACROCYCLIC POLYFUNCTIONAL LEWIS BASES-IX AZACROWN ETHERS
Biernat, Jan F.,Luboch, Elzbieta
, p. 1927 - 1930 (2007/10/02)
Several new diazacrown ethers and one tetraazacrown ether have been obtained.
SYNTHESIS OF N-UNSUBSTITUTED DI- AND TRIAZA CROWN ETHERS.
Maeda,Furuyoshi,Nakatsuji,Okahara
, p. 3073 - 3077 (2007/10/02)
Facile syntheses of di- and triaza crown ethers by intramolecular cyclization of oligoethylene glycols containing two or three imino groups or by their intermolecular cyclization with oligoethylene glycol bis(p-toluenesulfonate)s are described.
