نتایج جستجو برای: 12 crown 4 ether

تعداد نتایج: 1739084  

2012
Jie Xu Min-Min Zhao

In the title compound, C(6)H(7)ClN(+)·BF(4) (-)·C(12)H(24)O(6), the complete cation is generated by crystallographic mirror symmetry, with two C atoms and the N and Cl atoms lying on the mirror plane. The complete crown ether is also generated by mirror symmetry, as is the anion (in which the B and two F atoms lie on the mirror plane). The -NH(3) (+) group of the cation inserts into the crown-e...

2011
Mikio Ouchi

The synthesis and cation-binding properties of a series of Calixarene derivatives possessing alkyl chain groups, ester groups and crown ether rings have been investigated. The syntheses of Calix[4]arene crown ethers and Calix[6]arene derivatives possessing alkyl chain, ester group and crown ether ring have been described. In order to evaluate their monovalent cation binding abilities, solvent e...

2011
Qian Xu Min Min Zhao

The reaction of 4-bromo-3-methyl-anilinium perchlorate and 18-crown-6 in methanol solution yielded the title compound, C(7)H(9)BrN(+)·ClO(4) (-)·C(12)H(24)O(6). The protonated 4-bromo-3-methyl-amine unit contains one -NH(3) (+) substituent, resulting in a 1:1 supra-molecular rotator-stator structure, (C(7)H(9)Br-NH(3) (+))(18-crown-6), through three bifurcated N-H⋯(O,O) hydrogen bonds between t...

2006
Abbas Ali Mohammad Reza

The extraction-separation of lanthanum and europium ions with bis(2-ethylhexyl) phosphoric acid (DEHPA) in cyclohexane was improved by adding 12-crown-4 (12C4) to the aqueous phase as a masking agent. In the presence of this crown ether the extraction curve of lanthanum ions versus pH shifts to the higher pH region, while the curve is not influenced for the europium ions. Consequently the separ...

Journal: :Science 1988
C J Pedersen

The discovery of the crown ethers stemmed from efforts to control the catalytic activity of vanadium and copper by complexation with multidentate ligands. The first crown ether, 2,3,11,12-dibenzo-1,4,7,10,13,16-hexaoxacyclo-octadeca-2,11-diene, was obtained in 0.4% yield during an attempt to prepare a phenolic ligand from catechol and bis(2-chloroethyl)ether. This compound, which complexed with...

2013
K. Rajarajan A. Pugazhenthi M. NizamMohideen

The reaction of CdCl(2), 18-crown-6 and KI in water yields the title coordination polymer, [{K(C(12)H(24)O(6))}(2)Cd(2)I(6)](n). The potassium ion lies approximately in the plane of the crown ether, coordinated by all six crown ether O atoms and also by an iodide anion bound to a cadmium atom. A C atom of the crown ether is disordered over two positions with site occupancies of 0.77 (2) and 0.2...

2010
Jia-Zhen Ge Min-Min Zhao

In the title compound, C(7)H(10)N(+)·BF(4) (-)·C(12)H(24)O(6), the proton-ated 4-methyl-anilinium cation inter-acts with 18-crown-6 forming a rotator-stator structure, (C(6)H(4)CH(3)NH(3) (+))(18-crown-6), through three bifurcated N-H⋯(O,O) hydrogen bonds between the ammonium groups of the cations (-NH(3)) and the O atoms of the crown ether mol-ecule. The BF(4) (-) anions, the methyl group and ...

1998
Hans J. Reich D. Patrick Green Marco A. Medina Wayne S. Goldenberg Nancy H. Phillips

Phenyllithium forms a mixture of tetramer and dimer in ether. Complete conversion to dimeric solvates is achieved by the addition of THF, dioxolane, DME, or TMEDA in near stoichiometric amounts. The addition of 2,5-dimethyltetrahydrofuran favors dimer, but tetramer is still detectable at 14 equiv of cosolvent. PMDTA converts PhLi to monomer in ether. In THF, PhLi is a mixture of dimer and monom...

2011
Chun-Hua Yu

In the title compound, C(6)H(7)ClN(+)·ClO(4) (-)·C(12)H(24)O(6), the cation forms a 1:1 complex with the crown ether, viz [C(6)H(7)ClN-(18-crown-6)](+), in which the -NH(3) (+) unit nests in the crown and inter-acts with it through bifurcated N-H⋯O hydrogen bonding. All constituents of the structure have crystallographically imposed mirror symmetry except for the H atoms of the -NH(3) (+) group...

Journal: :Dalton transactions 2006
Benjamin R Elvidge Stefan Arndt Thomas P Spaniol Jun Okuda

Rare-earth metal alkyl tri(tert-butoxy)silanolate complexes [Ln{mu,eta2-OSi(O(t)Bu)3}(CH2SiMe3)2]2 (Ln = Y (1), Tb (2), Lu (3)) were prepared via protonolysis of the appropriate tris(alkyl) complex [Ln(CH2SiMe3)3(thf)2] with tri(tert-butoxy)silanol in pentane. Crystal structure analysis revealed a dinuclear structure for with square pyramidal geometry at the yttrium centre. The silanolate ligan...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید