- Synthesis of new N-pivot lariat crown ethers containing a propylene linkage in the side arm
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A series of new 15- and 18-membered N-pivot lariat aza-crown ethers having a propylene linkage in the side arm was prepared starting from functionalized diethanolamines and functionalized lariat aza-crown ethers containing the easily modified benzotriazole moiety. Addition reactions of such derivatives to electron-rich vinyl ethers or vinylamides followed by displacement of the benzotriazolyl group in the addition products by hydrogen (by reduction with LiAlH4) gives a variety of N-(3-oxo-3-substituted)- and N-(3-aza-3-substituted)propylene side-armed derivatives of aza-crown ethers. Stability constants for the complexes of several synthesized lariats with metal cations are discussed.
- Katritzky, Alan R.,Denisko, Olga V.,Belyakov, Sergei A.,Schall, Otto F.,Gokel, George W.
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- Barium complexes with crown-ether-functionalised amidinate and iminoanilide ligands for the hydrophosphination of vinylarenes
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The detailed multistep syntheses of two nitrogen-based sterically congested iminoanilidine and amidine proligands bearing a tethered 15-member aza-ether-crown macrocycle, namely {I^Acrown}H and {Amcrown}H, are reported. These proligands react with [Ba{N(SiMe2H)2}2·(thf)n] to generate the heteroleptic barium complexes [{I^Acrown}BaN(SiMe2H)2] (5) and [{Amcrown}BaN(SiMe2H)2] (6) in high yields. These complexes exhibit high coordination numbers (resp. eight and seven) and are in addition stabilised by mild Ba?H-Si interactions. Unusually for oxophilic elements such as barium, the amidinate ligand in 6 is only η1-coordinated. Complexes 5 and 6 mediate the intermolecular hydrophosphination of styrene with primary (PhPH2) and secondary (HPPh2) phosphines. Their catalytic performance compares favourably with those of other barium precatalysts for these reactions. During the course of the hydrophosphination of styrene with HPPh2 catalysed by 5, the phosphide complex [{I^Acrown}BaPPh2] (7) could be intercepted and crystallographically characterised.
- Le Coz, Erwann,Roueindeji, Hanieh,Roisnel, Thierry,Dorcet, Vincent,Carpentier, Jean-Francois,Sarazin, Yann
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supporting information
p. 9173 - 9180
(2019/07/04)
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- Tridentate phosphine ligands bearing aza-crown ether lariats
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Crown ethers are useful macrocycles that act as size-selective binding sites for alkali metals. These frameworks have been incorporated into a number of macromolecular assemblies that use simple cations as reporters and/or activity triggers. Incorporating crown ethers into secondary coordination sphere ligand frameworks for transition metal chemistry will lead to new potential methods for controlling bond formation steps, and routes that couple traditional ligand frameworks with these moieties are highly desirable. Herein we report the syntheses of a family of tridentate phosphine complexes bearing tethered aza-crown ethers (lariats) designed to modularize the variation of aza-crown size, lariat length, and distal phosphine substituents, followed by the synthesis and solid-state structures of Mo(III) complexes bearing cations in the pendent crown ethers.
- Pap, Levente G.,Arulsamy, Navamoney,Hulley, Elliott B.
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supporting information
p. 385 - 392
(2017/11/30)
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- Synthesis of monoazacrown ethers under phase-transfer catalysis
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A procedure has been proposed for the synthesis of monoazacrown ethers by reaction of N-benzyldiethanolamine with oligo(ethylene glycol) bis-p-toluenesulfonates in a two-phase system aromatic hydrocarbon-50% aqueous alkali, followed by removal of the benzyl group by catalytic hydrogenolysis. The maximal yields of N-benzylaza-12-crown-4, -18-crown-6, and -21-crown-7 were achieved by adding 4-10 equiv of LiCl, BaBr2, and CsCl, respectively, to the reaction mixture, which probably indicated template effect. Pleiades Publishing, Ltd., 2012.
- Luk'yanenko,Basok,Kulygina, E. Yu.,Bogashchenko, T. Yu.,Yakovenko
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p. 1345 - 1352
(2013/02/22)
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- Synthesis of N-(bisphosphonomethyl)-aza-15-Crown-5 and N- (bisphosphonomethyl)-aza-18-crown-6 ethers as artificial ion channels: An approach to channel-type molecular structures
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We report the synthesis and characterization of 2 new N- (bisphosphonomethyl)-aza-15-crown-5 1a and N-(bisphosphonomethyl)-aza-18-Crown-6 ethers 1b designed to further investigate the supramolecular assemblies based on exocyclic functional groups of crown ethers. Copyright Taylor & Francis LLC.
- Fallouh,Bernier,Virieux,Cristau,Pirat
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p. 219 - 225
(2007/10/03)
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- Fluorescence enhancement of a signaling system in the simultaneous presence of transition and alkali metal ions: A potential AND logic gate
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Attachment of a laterally non-symmetric cryptand and a macrocycle at the 9- and 10-positions of anthracene leads to a fluorescent signaling system L 1 which gives fluorescence enhancement in the simultaneous presence of alkali and transition metal ions.
- Bag, Bamaprasad,Bharadwaj, Parimal K.
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p. 513 - 515
(2008/09/18)
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- Effects of metal ions on physicochemical properties and redox reactivity of phenolates and phenoxyl radicals: Mechanistic insight into hydrogen atom abstraction by phenoxyl radical-metal complexes
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Phenolate and phenoxyl radical complexes of a series of alkaline earth metal ions as well as monovalent cations such as Na+ and K+ have been prepared by using 2,4-di-tert-butyl-6-(1,4,7,10-tetraoxa-13-aza-cyclopentadec-13-ylmethyl) phenol (L1H) and 2,4-di-tert-butyl-6-(1,4,7,10,13-pentaoxa-16-aza-cyclo-octadec-16-ylmethyl) phenol (L2H) to examine the effects of the cations on the structure, physicochemical properties and redox reactivity of the phenolate and phenoxyl radical complexes. Crystal structures of the Mg2+- and Ca2+-complexes of L1- as well as the Ca2+- and Sr2+-complexes of L2- were determined by X-ray crystallographic analysis, showing that the crown ether rings in the Ca2+-complexes are significantly distorted from planarity, whereas those in the Mg2+- and Sr2+-complexes are fairly flat. The spectral features (UV-vis) as well as the redox potentials of the phenolate complexes are also influenced by the metal ions, depending on the Lewis acidity of the metal ions. The phenoxyl radical complexes are successfully generated in situ by the oxidation of the phenolate complexes with (NH4)2[Ce4+(NO3)6] (CAN). They exhibited strong absorption bands around 400 nm together with a broad one around 600-900 nm, the latter of which is also affected by the metal ions. The phenoxyl radical-metal complexes are characterized by resonance Raman, ESI-MS, and ESR spectra, and the metal ion effects on those spectroscopic features are also discussed. Stability and reactivity of the phenoxyl radical-metal complexes are significantly different, depending on the type of metal ions. The disproportionation of the phenoxyl radicals is significantly retarded by the electronic repulsion between the metal cation and a generated organic cation (Ln+), leading to stabilization of the radicals. On the other hand, divalent cations decelerate the rate of hydrogen atom abstraction from 10-methyl-9,10-dihydroacridine (AcrH2) and its 9-substituted derivatives (AcrHR) by the phenoxyl radicals. On the basis of primary kinetic deuterium isotope effects and energetic consideration of the electron-transfer step from AcrH2 to the phenoxyl radical-metal complexes, we propose that the hydrogen atom abstraction by the phenoxyl radical-alkaline earth metal complexes proceeds via electron transfer followed by proton transfer.
- Itoh,Kumei,Nagatomo,Kitagawa,Fukuzumi
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p. 2165 - 2175
(2007/10/03)
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- MACROHETEROCYCLES. 25. CONVENIENT SYNTHESIS OF CROWN-COMPOUNDS WITH THIOCARBAMIDE GROUPS
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The reaction of polyoxyethylene diamines with polyoxyethylene diisothiocyanates leads to new crowns with thiocarbamide groups having 13- to 34-membered rings.Binuclear crown compounds with thiocarbamide groups are prepared by the reaction of polyoxyethylene diisothiocyanates with aza-15-crown-5
- Luk'yanenko, N. G.,Kirichenko, T. A.,Limich, V. V.,Bogatskii, A. V.
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p. 222 - 225
(2007/10/02)
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- Direct ESR Evidence for Sodium Selective, Intramolecular Ion Pairing in Redox-Switched Nitrogen-Pivot Lariat Ethers
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N-(2-Nitrobenzyl)aza-15-crown-5, 1, and the sidearm hexadeuterio analogue 2 have been reduced electrochemically to their corresponding radical anion forms and analyzed by ESR.Addition of Li(1+), Na(1+), or K(1+) to the solutions leads to changes in the ESR spectra but the changes are most marked when Na(1+) is present.Essentially no change is observed in the ESR spectrum of 2-nitrotoluene, confirming that both macroring and sidearm must be involved for the intramolecular ion pair to be stable.The radical anion sidearm compexes must be relatively rigid species since the strongest sidearm interaction is observed with Na(1+) cation which is closest in size to the cavity formed by the cooperating macroring and sidearm.
- Delgado, Milagros,Echegoyen, Luis,Gatto, Vincent J.,Gustowski, Deborah A.,Gokel, George W.
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p. 4135 - 4138
(2007/10/02)
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- Lipophilic Bis(monoaza crown ether) Derivatives: Synthesis and Cation-Complexing Properties
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Eleven lipophilic bis(monoaza crown ether) derivatives were synthesized, in which two monoaza crown ethers with 9-, 12-, 15-, or 18-membered rings are linked through the nitrogen atoms by an alkane-, diether-, or diester-type bridge chain bearing a dodecyl group.Sodium and potassium binding with the bis(monoaza crown ether) was determined potentiometrically and compared with those for previous bis(crown ethers) 5 (n = 1 - 3) and corresponding monocyclic analogues 4 and 6 (n = 1 - 3).Marked bis(crown ether) effect was observed only for the alkane-type bis(monoaza-12-crown-4) and bis(monoaza-15-crown-5) derivatives 1 (n = 1,2) on complexing Na+ and K+, respectively.It was suggested that in some of the other bis(monoaza crown ethers) lariat-ether effect works instead.Bis(monoaza-9-crown-3) derivatives 1 and 2 (n = 0) possess very poor cation-complexing ability.Acidity constant values gave some hints about the bis(crown ether) effect.
- Sakamoto, Hidefumi,Kimura, Keiichi,Koseki, Yasuaki,Matsuo, Mitsunori,Shono, Toshiyuki
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p. 4974 - 4979
(2007/10/02)
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- Na+ Complexation of New Multidentate Polyether Ligands - Rapid Estimation of Complexation Constants by 23Na NMR Spectroscopy
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A new 23Na NMR method for fast and simple estimation of Na+ complex stabilities is reported and applied to various polyether ligands.Synthesis of the new coronands and podands amongst the employed substrates are given.
- Offermann, Werner,Weber, Edwin
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p. 234 - 245
(2007/10/02)
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- Synthesis of Monoaza Crown Ethers from N,N-Diamines and Oligoethylene Glycol Di(p-toluenesulfonates) or Corresponding Dichlorides
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Monoaza crown ethers were prepared in satisfactory yields by the one-step reaction between diethanolamine or N,N-diamines and oligoethylene glycol di(p-toluenesulfonates) or corresponding dichlorides in t-butyl alcohol/dioxane in the presence of sodium or potassium t-butoxide.The reaction conditions in the preparation of monoaza 15- and 18-crown ethers were studied.Various monoaza crown ethers having substituents were also prepared and their properties were investigated.
- Maeda, Hirokazu,Furuyoshi, Shigeo,Nakatsuji, Yohji,Okahara, Mitsuo
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p. 212 - 218
(2007/10/02)
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- INTRAMOLECULAR CYCLIZATION OF N,N-Di(OLIGOOXYETHYLENE)AMINES: A NEW SYNTHESIS OF MONOAZA CROWN ETHERS
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The reaction of N,N-di(oligooxyethylene)amines with arenesulfonyl chloride in the presence of alkali metal hydroxide was investigated.It was found that the monoarenesulfonates of N,N-di(oligooxyethylene)amines were first formed as intermediates, and their subsequent intramolecular cyclization gave N-unsubstituted monoaza crown ethers rather selectively.
- Maeda, Hirokazu,Furuyoshi, Shigeo,Nakatsuji, Yohji,Okahara, Mitsuo
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p. 3359 - 3362
(2007/10/02)
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- Effect of Chain Length and Heteroatom Position on Ammonium Ion Binding in Nitrogen-containing "Lariat" Ethers
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Macrocyclic polyethers having polyethyleneoxy-sidechains extending from a nitrogen pivot bind ammonium ions quite strongly when an 18-membered ring and a two-oxygen sidechain are present; a 15-membered ring and other chain lengths give inferior binding.
- Schultz, Rose Ann,Schlegel, Eric,Dishong, Dennis M.,Gokel, George W.
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p. 242 - 243
(2007/10/02)
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- Neue Chromoionophore
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The synthesis and spectroscopic properties, especially shifts in light absorption upon addition of salts, of the new ionophore dyes 1, 3, 4, 10, and 11 of the anthraquinone-, naphthoquinone-, and phenol blue type are described.The observed hypsochromic and bathochromic shifts are discussed in view of the crown ether complexation in the donor or acceptor part, resp., or with 3 and 4 in view of the coordination at both donor and acceptor.Influences of the ion size and of the charge density as well as the influence of changes of the cyanine and polyene character are explained.
- Dix, Johannes Peter,Voegtle, Fritz
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p. 638 - 651
(2007/10/02)
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- SYNTHESIS OF N-CYANO MONOAZA CROWN ETHERS
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N-Cyano monoaza crown ethers were prepared by the reaction of cyanamide with oligoehtylene glycol dichlorides or ditosylates in the NaH/DMSO reaction system and led to the derivatives.
- Maeda, Hirokazu,Nakatsuji, Yohji,Okahara, Mitsuko
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p. 4105 - 4106
(2007/10/02)
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- Facile Synthesis of Monoaza Crown Ethers
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A facile one-step synthesis of monoaza crown ethers by treatment of dialkanolamines with oligoethylene glycol di(toluene-p-sulphonates) or dichlorides in ButOM-ButOH (M = Na, K) is described.
- Maeda, Hirokazu,Nakatsuji, Yohji,Okahara, Mitsuo
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p. 471 - 472
(2007/10/02)
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