Ion-exchange properties of crown ether-phosphomolybdic acid precipitates

Extraction with Metal Bis(dicarbollide) Anions

“…An interesting feature of these precipitates is the way to prepare them; in the case of crown ethers the two starting components are not soluble in the same solvent. The mechanism of sorption on the first material mentioned above was later studied by Fernando [281] and it was ascertained that sorption primarily takes place only at the surface of the solid phase. It is only natural that analogous precipitates will form with cobalt bis(dicarbollide) anions; however, at this time they were not studied due to the deemed high price of cobalt bis(dicarbollide) compounds at the beginning of the investigations.…”

Thermodynamic investigations of complexation between dibenzo 18-crown-6 with Ni2+, Zn2+ and Cd2+ cations in pure acetonitrile, pure dimethylesulfoxide and acetonitrile-dimethylesulfoxide binary mixtures using conductometric method

“…The selectivity and stability of crown ethers complexes with cations are reliant on several factors like, cavity size of crown ether, the number and type of the donor atoms, the charge density and polarizability of the cation and cation diameter [2,3]. Crown ethers have been established to be highly selective complexing agents for many metal cations and can potentially be applied in their separation [4][5][6][7] and determination. Crown ethers have been used in different areas, such as organic synthesis [8], chemical analysis [9], in construction of ion selective electrodes [10,11], separation of metal cations [12,13].…”

A copper–cyclen coordination complex associated with a polyoxometalate anion: Synthesis, crystal structure and electrochemistry of [Cu(cyclen)(MeCN)][W6O19]

“…In other words, combination of the azacrown-ethers with POM anions can be used to separate specific metal ions (depending on cavity size of the aza-crown ethers) from an aqueous solution by precipitation method. Usage of the POM cluster anions in combination with the crown ethers has been described in the separation of radioactive wastes [12][13][14]. Structural, topological and electronic diversities are the key aspects of the chemistry associated with POM anions [15][16][17][18].…”

“…Geometrical parameters for hydrogen bonding interactions: C (1)-H(1A)⋯O(5) 0.97, 2.68 and 3.601(15) Å, 159.4°(− x + 0.5, y + 0.5); C(2)-H(2A)⋯O (3) 0.97, 2.50 and 3.315 (14) Å, 141.4°(− x + 1, y, − z + 0.5); N(1)-H(1 N)⋯O(7) 0.88 (11), 2.44(11) and 3.301(13) Å, 169(10)°(x, − y, z + 0.5); N(2)-H(2 N)⋯O(4) 0.79(11), 2.46(12) and 3.175(14) Å, 151(11)°. Selected bond lengths: C(1) N(1) 1.432(17), C (2) N(1) 1.503(16), C(2) C(3) 1.511(17), C(3) N(2) 1.432(18), C(4) N(2) 1.508(18), C (5) N(3) 1.11(2), C(5) C(6) 1.44(2), Cu(1) N(2) 2.004(12), Cu(1) N(1) 2.035(11), Cu (1) N(3) 2.070(14).…”