نتایج جستجو برای: 18 and 24 crown ethers

تعداد نتایج: 16918122  

Journal: :Macromolecular Chemistry and Physics 2022

Abstract In‐depth understanding of copolymerization kinetics and the resulting polymer microstructure is crucial for design materials with well‐defined properties. Further, insights regarding impact solvents on allows precisely tuned materials. In this regard, in situ 1 H NMR spectroscopy enables precise monitoring living anionic ring‐opening (AROP) ethylene oxide (EO) glycidyl ethers allyl eth...

Journal: :Chemical & pharmaceutical bulletin 2008
Akimori Wada Fei Wang Masayoshi Ito

A convenient synthesis of 3,4-didehydroretinal was developed. The Horner-Emmons reaction between 3,4-didehydro-beta-ionone and diphenyl phosphonate in the presence of crown ether gave the retinonitrile as an isomeric mixture, in which the newly produced double bond was predominantly 11Z-form. After separation of the 11Z-form retinonitrile, it was converted into the corresponding retinal in good...

Journal: :Chemical communications 2016
Kirsten Reuter Günther Thiele Thomas Hafner Frank Uhlig Carsten von Hänisch

The first hybrid crown ether with two adjacent disilane fragments was synthesized through reaction of O(Si2Me4Cl)2 (3) with O(C2H4OH)2. By means of DFT calculations, the complexation ability of 1,2,4,5-tetrasila[12]crown-4 (7) towards Li+ was determined to be considerably higher compared to [12]crown-4.

Journal: :Bulletin of the Chemical Society of Japan 1979

Journal: :Chemical communications 2008
Alan R Kennedy Jan Klett Robert E Mulvey Sean Newton Dominic S Wright

Extending to transition metals, the class of compounds known as inverse crown ethers, two mixed alkali metal-manganese(II) amide ring compounds with oxo cores have been synthesised and crystallographically characterised, together with an oxo-free alkyl-amido precursor.

2015
Ken Cham-Fai Leung Kwun-Ngai Lau Wing-Yan Wong

A new [2]pseudorotaxane DB24C8⊃1-H · PF6 with dibenzo[24]crown-8 (DB24C8) crown ether-dibenzylammonium (1-H · PF6) binding which was formed by slippage approach at different solvents and temperature, had been isolated and characterized by NMR spectroscopy and mass spectrometry. The [2]pseudorotaxane DB24C8⊃1-H · PF6 was stable at room temperature. The dissociation rate of [2]pseudorotaxane DB24...

2012
Bin Wei

In the crystal of the title compound, 2CH(6)N(3) (+)·C(10)H(6)O(6)S(2) (2-)·C(12)H(24)O(6), the 1,5-naphthnalenedisulfonate anion and the 18-crown-6 mol-ecule lie across inversion centers. The guanidin-ium cation links with the 1,5-naphthnalenedisulfonate anion and 18-crown-6 mol-ecule via N-H⋯O hydrogen bonds.

2012
Bin Wei

In the crystal of the title compound, 2CH(6)N(3) (+)·2Cl(-)·C(12)H(24)O(6), the 18-crown-6 mol-ecule is located across an inversion center. The guanidinium cation links to the 18-crown-6 mol-ecule and chloride anion via N-H⋯O and N-H⋯Cl hydrogen bonds.

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