نتایج جستجو برای: crown ether addition
تعداد نتایج: 750363 فیلتر نتایج به سال:
Complex formation between the silver(I) ion and monoazaand diaza-crown ethers has been studied in five polar, nonaqueous solvents using potentiometric techniques. The stability constants are spread over seven orders of magnitude, and the major contributor to this variation is the solvation of the silver(I) cation. The ring-size dependence of the stability constants is determined both by the cor...
The sensing response of 15-crown-5-ether functionalized polythiophene to Li+, Na+, and K+ has been investigated at the atomistic level using molecular dynamics simulations. The stability associated with all the identified binding sites has been corroborated by quantum mechanical calculations. Although the cavity of the macrocycle is not the most visited binding site, such receptor is responsibl...
The template-directed synthesis of a bistable donor-acceptor [2]catenane wherein both translational isomers--one in which a tetrathiafulvalene unit in a mechanically interlocked crown ether occupies the cavity of a cyclobis(paraquat-p-phenylene) ring and the other in which a 1,5-dioxynaphthalene unit in the crown ether resides inside the cavity of the tetracationic cyclophane--exist in equilibr...
Ru(bpy)2(CE-bpy)2+ was prepared where bpy and CE-bpy were 2,2'-bipyridine and bpy having a crown-ether moiety at the 3,3'-positions, respectively. Although Ru(bpy)2(CE-bpy)2+ showed only very weak emission in acetonitrile, recognition of Na+, Li+, or K+ by the crown-ether moiety in CE-bpy resulted in increases in both the emission intensity and the lifetime of the complex, demonstrating that it...
Water soluble gold nanoparticles protected by lipoic acid were obtained and further functionalized by standard coupling reaction with 1-naphtylamine, 4-aminoantipyrine, and 4'-aminobenzo-15-crown-5 ether. Derivatives of lipoic acid with 1-naphtylamine, 4-aminoantipyrine, and 4'-aminobenzo-15-crown-5 ether were also obtained and characterized. All these were tested for their antimicrobial activi...
The title compound, C33H35N3O5, is the product of the multicomponent condensation of 1-benzyl-4-eth-oxy-carbonyl-piperidin-3-one with 1,5-bis-(2-formyl-phen-oxy)-3-oxapentane and ammonium acetate. The mol-ecule comprises a penta-cyclic system containing the aza-14-crown-4-ether macrocycle, tetra-hydro-pyrimidine, tetra-hydro-pyridine and two benzene rings. The aza-14-crown-4-ether ring adopts a...
In the title compound, [K(2)PtCl(4)(C(12)H(24)O(6))(2)], the Pt(II) ion is located on an inversion centre and is coordinated by four Cl atoms, forming a square-planar geometry. The K(I) ion is coordinated by six O atoms of the crown ether and two bridging Cl atoms. The K(I) ion is displaced by 0.756 (2) Å from the mean plane of the six O atoms of the crown ether. The mol-ecules are connected by...
The title compound, C24H29NO4, is the product of a Petrenko-Kritchenko condensation of 1,5-bis-(2-formyl-phen-oxy)-3-oxa-pentane, pentan-3-one and methyl-ammonium acetate in ethanol. The mol-ecule has mirror symmetry. The aza-14-crown-3 ether ring adopts a bowl conformation stabilized by a weak intra-molecular C-H⋯O hydrogen bond. The conformation of the C-O-C-C-O-C-C-O-C polyether chain is t-g...
Dispersing metal–organic framework (MOF) solids in stable colloids is critical for their availability and processibility. In Communication (e202303280), Hang Xing et al. report a crown ether surface coordination approach that enables the universal suspension of various MOF powders into immiscible polar nonpolar solvents, exhibiting exceptional dispersibility without compromising accessible void...
To probe the influence of electrostatic interactions on the mesomorphic self-assembly and phase behaviour of hybrid liquid crystals a series of crown ether/tyrosine hybrid systems was prepared by Steglich esterification of alkyl N-(tert-butoxycarbonyl)-l-tyrosinates with 4-carboxybenzo[15]crown-5 and 4-carboxybenzo[18]crown-6. The obtained derivatives allowed further manipulations at the NH fun...
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