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1.
Derivatives of 12-crown-4 and 18-crown-6 in which one of the ethereal oxygens is replaced by a CO group have been synthesised and their complexing abilities towards both metal and organic cations have been assessed. Variable temperature 1H decoupled 13C n.m.r. spectroscopy reveals the presence of anisometric species in solution when a :1 complex is formed between oxo-18-crown-5 and (S)-PhCHMeNH3+ClO4. 相似文献
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Junzo Yamashita Hideaki Takahashi Harukichi Hashimoto Keiichi Kitahara Hisao Sato 《Journal of inclusion phenomena and macrocyclic chemistry》1984,2(1-2):145-151
The chiral recognition properties of chiral 18-crown-6 ethers with phenyl, 1-naphthoxymethyl, 1-naphthylmethyl, or 2,3,5,6-tetramethylphenylmethyl substituents for -phenylglycine methyl ester and 1-phenylethylamine perchlorate were investigated by a standard extraction procedure. The chiral recognition factor of 1-naphthoxymethyl substituted crown ether is 2.0 for the former salt but near 1.0 for the latter, whereas that of the other crown ethers is not so dependent on the structure of salts, which indicates the importance of the mutual relation of the structure of host and quest molecules. 相似文献
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Bis-crown ethers in which the benzo-15-crown-5 units were linked to 1,1′-positions of metallocene (M = Fe or Ru) with amide, ester, or ? C? C? bonds were synthesized. Complexing ability of the compounds with alkali, alkali earth, and transition metal cations were measured by the solvent extraction method. The results showed that these crown ethers had high affinity toward alkali metal cations (Li+, Na+, K+, and Rb+) and heavy-metal cations (Ag+ and Tl+). The difference of complexing ability for metal cations between ferrocene and ruthenocene derivatives could not be detected significantly. The extractability of metallocene-bis-crown ethers for metal cations was more larger than that of the corresponding mono-crown ethers, and irregular increments of extractability were explained by assuming the existence of a mixture of 1:1 and 2:1 complexes. 相似文献
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O. A. Fedorova Yu. P. Strokach A. V. Chebun’kova T. M. Valova S. P. Gromov M. V. Alfimov V. Lokshin A. Samat 《Russian Chemical Bulletin》2006,55(2):287-294
Complex formation of Mg2+, Ba2+, and Pb2+ perchlorates with 3,3-diphenyl-3H-benzo[f]chromenes containing aza-and diaza-18-crown-6-ether or morpholine fragments was studied. The strong influence of the metal
cations on the spectral characteristics of these organic ligands and on the kinetic of photochromic transformations was found.
The results obtained were explained by the formation of carbonyl-“ capped” complexes of various structures.
Faculte des Sciences de Luminy, Universite de la Mediterranee, UMR 6114 CNRS, 13288 Marseille, France.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 280—287, February, 2006. 相似文献
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Javad Zolgharnein Ghasem Shahmoradi Khosrow Zamani Saeid Amani 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(1-2):99-103
The complexation reaction of phenylaza-15-crown-5, and 4-nitrobenzo-15-crown-5, benzo-15-crown-5 and dibenzopyrdino-18-crwon-6,
dibenzo-18-crown-6,dicyclohexyl-18-crown-6(cis and trans), and 18-crown-6 with Na+ ion in methanol have been studied by potentiometric method. The Na+ ion-selective electrode has been used both as indicator and reference electrode. The stoichiometry and stability constants
of complexes of these crown ethers with sodium ion were evaluated by MINIQUAD program. The major trend of stability of resulting
complexes of these macrocycle with Na+ ion varied in the order DCY18C6 > DB18C6 > 18C6 > DBPY18C6 > phenylaza-15C5 > benzo-15C5 > 4-nitrobenzo-15C5. The obtained
results in particular stability constant of complexes of DBPY18C6, phenylaza-15C5 and 4-nitrobenzo-15C5 with sodium ion in
comparison with other crowns ether are novel, and interesting. 相似文献
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V. A. Popova I. V. Podgornaya V. G. Lundina L. I. Kurnikova A. I. Tarasov 《Russian Chemical Bulletin》1987,36(11):2361-2364
Conclusions Complex compounds of bisacyl derivatives of diaminodibenzo-18-crown-6 ether are active catalysts of the two stages of the synthesis of poly(ethylene terephthalate).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2544–2547, November. 1987. 相似文献
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Jerald S. Bradshaw Christopher W. Mcdaniel Krzysztof E. Krakowiak Reed M. Izatt 《Journal of heterocyclic chemistry》1990,27(5):1477-1479
Four new chiral macrocyclic polyether ligands containing the proton-ionizable triazole subcyclic unit have been prepared. The triazolo-crowns contain two isopropyl, two isobutyl, two (S)-sec-butyl or two benzyl substituents on chiral macro ring carbon atoms. A racemic triazolo-18-crown-6 containing two (1-naphthoxy)methyl substituents was also prepared. 相似文献
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[structure: see text] 4-tert-Butyl-1-cyclohexenyl(phenyl)(tetrafluoroborato)-lambda(3)-iodane forms a discrete supramolecular complex by the reaction with 18-crown-6. Solvolysis of the cyclohexenyl-lambda(3)-iodane in the presence of 18-crown-6 indicates that the complexation with 18-crown-6 tends to decrease the leaving group ability of hypervalent phenyl-lambda(3)-iodanyl groups. 相似文献
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《Tetrahedron letters》1986,27(35):4185-4188
The diastereoface selection is described in the title rearrangement of chiral 2-oxazoline systems either in the absence or the presence of 18-crown-6. The dramatic effects of the K+ counterion and its complexation with the crown ether are noted. 相似文献
16.
Two constitutional isomers of dibenzo-18-crown-6 derivatives (6 and 7) were synthesised and their binding behaviours towards trivalent lanthanoid cations (La3 + , Ce3 + , Pr3 + , Nd3 + , Sm3 + , Eu3 + , Gd3 + and Tb3 + ) were investigated. Both isomers expressed better binding affinities towards Sm3 + and Tb3 + than a group of other lanthanoids, as measured by the ligand-to-metal charge-transfer (LMCT) band intensity at ca. 425 nm using UV–vis spectroscopic method. Additionally, the trans isomer 7 was shown to have a higher binding ability than the cis isomer 6 towards Tb3 + . 相似文献
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Jerald S. Bradshaw Peter Huszthy Tingmin Wang Chengyue Zhu Alexander Y. Nazarenko Reed M. Izatt 《Supramolecular chemistry》2013,25(3-4):267-275
Abstract Optically pure allyloxy and dimethyl-substituted pyridino-18-crown-6 (8) was attached to silica gel by the following reactions. 4-Allyloxy-2,6-pyridinedimethyl ditosylate (23) was first prepared from chelidamic acid. Ditosylate 23 was treated with (S,S)-dimethyl-substituted tetraethylene glycol to form 8. Ligand 8 was treated with triethoxysilane using a platinum catalyst. The resulting chiral crown-substituted triethoxysilane 32 was reacted with silica gel in toluene at 90 C to attach the crown to silica gel. Preliminary results of the separation of [α-(1-naphthyl)ethyl]ammonium perchlorate into its (R) and (S) forms using the bound chiral crown with acetone/methanol (7/3) (v/v) as the eluant are reported. The preparation of chiral dimethyl(allyloxyphenyl)pyridino-18-crown-6 (9) that could be attached to silica gel on the side opposite to the pyridine ring is also reported. 相似文献
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Peter Bak Laszl Fenichel Laszl T
ke Bruce E. Davison Alpana Patel 《Heteroatom Chemistry》1994,5(4):415-419
The synthesis of bis-(1,2-O-isopropylidene-6-O-triphenylmethyl-α-D-glucofuranosyl)-20-crown-6 ( 1 ) and its complexing ability with alkali and ammonium cations are described. The crown ether 1 was synthesized in a stepwise manner via the “half-crown” ( 2 ) using a blocking-deblocking procedure, in which the 3,3′-bridge was formed, followed after suitable manipulations, by formation of the 5,5′-bridge. An unusual feature of the complexing ability of the crown ether is that, although potassium and ammonium ions most closely approach the size of the complexing cavity, it is the sodium ion which forms the most stable complex. Compound 1 does not show chiral recognition toward two alkylammonium salts. 相似文献
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Keiji Hirose Takashi NakamuraRyota Nishioka Tetsuro UeshigeYoshito Tobe 《Tetrahedron letters》2003,44(8):1549-1551
Novel chiral stationary phases consisting of silica gel covalently bound with chiral pseudo-18-crown-6 type hosts, which possess either an OH or OMe group as a binding functionality, were prepared for enantiomer-separation of lipophilic amines. 相似文献