Influence of peripheral substituents on the stability of sandwich-type complexes of crown ether-containing anthraquinoneimines

2018 ◽  
Vol 30 (11) ◽  
pp. 918-928
Author(s):  
Timofey P. Martyanov ◽  
Aleksandra A. Kudrevatykh ◽  
Igor G. Strelnikov ◽  
Lubov S. Klimenko ◽  
Denis V. Korchagin ◽  
...  
Keyword(s):  
Crown Ether ◽  
Sandwich Type ◽  
The Stability

Polycarboxylate crown ethers from meso-tartaric acid

1991 ◽  
Vol 69 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Frank R. Fronczek ◽  
Richard D. Gandour ◽  
Thomas M. Fyles ◽  
Philippa J. Hocking ◽  
Susan J. McDermid ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crown Ether ◽  
Tartaric Acid ◽  
Crown Ethers ◽  
Nmr Spectra ◽  
Product Distribution ◽  
Complexing Agents ◽  
Triclinic Space Group ◽  
The Stability ◽  
Ether Synthesis

The synthesis of crown ethers derived from meso-tartaric acid was investigated. The sodium salt of the bis(dimethylamide) of meso-tartaric acid reacted with diethylene glycol ditosylate to give a mixture of 18-crown-6 tetraamide and 27-crown-9 hexaamide crown ethers. The 2R,3S,11S,12R 18-crown-6 isomer crystallized in triclinic space group [Formula: see text] (a = 7.557(2), b = 8.866(2), c = 10.4133(13) Å, α = 94.13(2), β = 95.86(2), γ = 99.26(2)°, R = 0.040 for 2090 observed of 3129 unique reflections). The structures of the remaining products were then assigned from the NMR spectra. The solution conformations of the amide crown ethers were examined by NMR, and provide a rationale for the product distribution obtained. One of the 18-crown-6 isomers and a mixture of the two 27-crown-9 isomers were hydrolyzed to the respective crown ether carboxylic acids, and the stability constants for complexation of cations were determined by potentiometric titration. The meso tetra- and hexacarboxylates are remarkably nonselective and inefficient cation complexing agents, compared to related crown ethers from R,R-(+)-tartaric acid, due to the unfavorable conformational control exerted by the tartaro units. Key words: crown ether synthesis, complexation, crown ether conformation, meso-tartaric acid, crystal structure.

The extraction of alkali metal picrates by polyurethane foam using crown ether

1981 ◽  
Vol 59 (10) ◽  
pp. 1490-1496 ◽  
Author(s):  
Anjum S. Khan ◽  
W. G. Baldwin ◽  
A. Chow
Keyword(s):  
Crown Ether ◽  
Alkali Metal ◽  
Polyurethane Foam ◽  
Dissociation Constants ◽  
Extraction Constant ◽  
Ion Pair ◽  
Constant Sequence ◽  
Extraction Constants ◽  
The Stability ◽  
Ether Complex

The distribution of alkali metal picrates between water and polyurethane foam was studied in the presence of dicyclohexyl 18-crown-6 (DCHC-6). The extraction constants and dissociation constants for the ion pair (MCrA) in polyurethane foam were determined. The extraction constant sequence of the alkali metal ions with DCHC-6 is K+ > Rb+ > Cs+ > Na+ and mainly depends on the stability of the alkali metal – crown ether complex.

Preparation and ESR studies of salts of crown ether complex cations and nitridotechnetium(VI) anions: structures of the twinned ‘infinite sandwich’ [Cs(18-crown-6)][TcNCl 4 ] complex and of [Rb(15-crown-5) 2 ] [TcNCl 4 (OH 2 )]

1993 ◽  
Vol 442 (1915) ◽  
pp. 437-461 ◽  
Keyword(s):  
Crown Ether ◽  
Exchange Interactions ◽  
Esr Spectra ◽  
Chain Structure ◽  
Polymeric Chain ◽  
Strong Electron ◽  
Disordered Lattice ◽  
Spin Resonance ◽  
Sandwich Type

We report the preparations and electron spin resonance (ESR) studies of a series of Cs + and Rb + crown ether (15-crown-5 and 18-crown-6) salts of [TcNCl 4 ] - and [MoOCl 4 ] - , and a new refinement of the X-ray structure of [Cs(18-crown-6)] [TcNCl 4 ] involving a twinned P4/n scattering model. This refinement addresses some unsatisfactory aspects of the original disordered model. The structure consists of an ‘infinite sandwich’ Cs + cation/crown ether configuration and polymeric [TcNCL 4 ] - anions, with Tc≡N distances of 1.561(36) Å, and anti-parallel chains of –––Tc≡N–––Tc≡N –––with Tc···Tc separations of 4.275(4) Å. The structure determination of [Rb(15-crown-5) 2 ][TcNCl 4 (OH 2 )] is also described and shows a lattice containing 2:1 ‘sandwich’-type crown ether/alkali-metal cations and isolated anions in the disordered lattice. The presence of Tc≡N infrared stretching frequencies at ca . 1074 cm -1 indicates the absence of strong electron donors coordinated to Tc in the sixth position (i. e. isolated anions), whereas the polymeric chain structure of [Cs(18-crown-6)] [TcNCL 4 ] is characterized by a Tc≡N stretching frequency of 1041 cm -1 . Three product compounds, the ‘infinite sandwich’ [Cs(18-crown6)][TcNCl 4 ], [Cs(18-crown-6)] [TcNCL 4 (OH 2 )] with two Tc≡N stretching frequencies at 1055 and 1046.5 cm -1 , and [Cs(18-crown-6) 2 ][TcNCl 4 containing 2:1 crown ether/Cs + ‘sand­wich’ cations and isolated [TcNCl 4 ] - anions, could be obtained from reaction of Cs + /18-crown-6 and [TcNCL 4 ] - depending on reaction conditions and solvent. The ESR spectra of [Cs(18-crown-6)] [TcNCl 4 ] over the temperature range 130-290 K indicate the presence of exchange interactions along the linear ––– Tc≡N––– Tc≡N––– chains. Spectra for other crown ether salts are consistent with isolated [TcNCL 4 ] - or [TcNCL 4 (OH 2 )] - anions, with dipolar broadening effects apparent.

The Stability and Management of “Sandwich” Type Slopes in Extrusive Rock Area

2012 ◽  
Vol 472-475 ◽  
pp. 1253-1256
Author(s):  
Hong Wei ◽  
Hong Wang
Keyword(s):  
Hainan Island ◽  
Soil Layers ◽  
Loose Soil ◽  
Late Tertiary ◽  
Sandwich Type ◽  
Extrusive Rock ◽  
Management Method ◽  
The Stability ◽  
Faulted Zone ◽  
Poor Stability

Northern area of Hainan Island is located in the south of Leiqiong faulted zone; new tectonic movement and volcanic activity have intense since late tertiary. Cenozoic volcano in the region is developed, various types of extrusive rocks widely distributed which often directly cumulate on the Cenozoic sedimentary soil layers, then covered by more loose soil, form a soft - hard - soft “sandwich” type slope with a poor stability. Based on the study of this slope and simulate its stability, this paper proposed this kind of slope's destruction mechanism as well as the management method

scholarly journals Influence of Electron-Donating Substituents on the Stability of Sandwich-Type Complexes of Crown-Containing Anthraquinoneimines

2020 ◽  
Vol 13 (1) ◽  
pp. 55-63
Author(s):  
Aleksandra A. Kudrevatykh ◽  
Timofey P. Martyanov ◽  
Evgeny N. Ushakov ◽  
Alexander V. Chernyak ◽  
Lubov S. Klimenko
Keyword(s):  
Sandwich Type ◽  
The Stability

scholarly journals Improved Electronic Transport in Ion Complexes of Crown Ether Based Columnar Liquid Crystals

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 74 ◽  
Author(s):  
Peter Staffeld ◽  
Martin Kaller ◽  
Philipp Ehni ◽  
Max Ebert ◽  
Sabine Laschat ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Crown Ether ◽  
Electronic Transport ◽  
Columnar Structure ◽  
Strong Increase ◽  
Temperature Dependent ◽  
X Ray ◽  
X Ray Scattering ◽  
Structural And Electronic Properties ◽  
The Stability

The Li+- and K+-complexes of new discotic mesogens, where two n-alkoxy-substituted triphenylene cores are connected by a central crown ether (12-crown-4 and 18-crown-6), provide interesting structural and electronic properties. The inter- and intra-columnar structure was investigated by small and wide angle X-ray scattering. The electronic and ionic transports were studied by temperature dependent photoconductivity and impedance spectroscopy, respectively. Besides a strong increase of the stability and the width of the columnar phases the presence of soft anions (iodide, thiocyanate, tetrafluoroborate) leads to an improved intra-columnar order. The hereby shortened stacking-distance of the triphenylene cores leads to a significant increase of the photoconductivity in the columnar mesophase. Furthermore, the ionic conductivity of the new materials was investigated on macroscopically aligned thin films. The existence of channels for fast cation transport formed by the stacked crown ether moieties in the centre of each column can be excluded. The cations are coordinated strongly and therefore contributing only little to the conductivity. The ionic conductivity is dominated by the anisotropic migration of the non-coordinated anions through the liquid, like side chains favouring the propagation parallel to the columns. Iodide migrates about 20 times faster than thiocyanate and 100 times faster than tetrafluoroborate.

A sandwich strand supramolecular complex: aquachloro(nitrilotriacetato-κ2 N,O)copper(II) 18-crown-6-ether trihydrate

2006 ◽  
Vol 62 (4) ◽  
pp. m804-m806
Author(s):  
Yun-Bo Jiang ◽  
Hui-Zhong Kou ◽  
Ru-Ji Wang ◽  
Ai-Li Cui
Keyword(s):  
Crown Ether ◽  
Water Molecule ◽  
Nitrilotriacetic Acid ◽  
Supramolecular Complex ◽  
Carboxyl Groups ◽  
Mirror Plane ◽  
Water Molecules ◽  
Sandwich Type ◽  
Ether Molecule ◽  
Hydrogen Bonded

The unexpected title compound, [Cu(C6H8NO6)Cl(H2O)]·C12H24O6·3H2O, was synthesized by crystallization of a mixture containing CuCl2·2H2O, nitrilotriacetic acid (H3NTA), KOH, 18-crown-6 and GdCl3·6H2O. The complex consists of a hydrogen-bonded polymeric structure, in which discrete Cu(H2NTA)(H2O)Cl units interact via the carboxyl groups and the coordinating water molecules with the crown ether molecules. No direct metal–crown ether bond exists in the infinite sandwich-type hydrogen-bonded structure. The copper complex lies on a mirror plane, which passes through Cu and all the coordinating atoms. The crown ether molecule lies on an inversion centre. One water molecule is disordered across the mirror plane.

Insights into the Effects of 2:1 “Sandwich-Type” Crown-Ether/Metal-Ion Complexes in Responsive Host–Guest Systems

2015 ◽  
Vol 119 (4) ◽  
pp. 1696-1705 ◽  
Author(s):  
Hai-Rong Yu ◽  
Jia-Qi Hu ◽  
Xiao-Hua Lu ◽  
Xiao-Jie Ju ◽  
Zhuang Liu ◽  
...  
Keyword(s):  
Crown Ether ◽  
Metal Ion ◽  
Metal Ion Complexes ◽  
Sandwich Type
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