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 s...

crown ethers 12-crown-4 (12c4), benzo-15-crown-5 (b15c5), 18-crown-6 (18c6), nitrobenzo-18-crown-6 (nb18c6) dibenzo-18-crown-6 (db18c6) and dicyclohexyl-18-crown-6 (dc18c6), dissolved in dichloromethane, are able to form oxonium-ion complexes in contact with aqueous sulfuric and hydrochloric acid solutions. this ability allows the transfer of cr(vi) oxanions from the acid media, through an orga...

On heating the hydrated complexes 18-Crown[6].M[H(2)PO(4)].xH(2)O (x= 2 for M = K, Rb; x= 1.5 for M = Cs), quantitatively prepared by mechanical mixing of crystalline 18-Crown[6] and M[H(2)PO(4)], to ca. 60 degrees C, water loss takes place, accompanied by the extrusion of the crown ether from the crystalline complex and followed by reconstruction of the inorganic phase M[H(2)PO(4)](M = K, Rb, ...

The structures of two derivatives of the bisdioxine diisocyanate 1, the bisurea 4 and the biscarbamate 5, are established by X-ray crystallography and DFT calculations. These compounds possess endo,endo structures, in the case of the bisurea 4 with two nearly parallel pendant chains. The X-ray structures are reproduced very well by DFT calculations. Similar endo,endo conformations are calculate...

In the title compound, C(6)H(5)Cl(3)N(+)·ClO(4) (-)·C(12)H(24)O(6), the perchlorate anion is disordered over two orientations in a 0.666 (17):0.334 (17) ratio. The ammonium group of the organic cation inserts into the crown ether ring and forms three bifurcated N-H⋯(O,O) hydrogen bonds to generate a supra-molecular complex. The macrocycle has approximate D(3d) local symmetry.

the macrocyclic ligands 2,3,5,6-bis{3’-bromo-5’-tert-butyl benzo-5-phenyl benzo} 12c3 (l1), 2,3,5,6-bis{3’-bromo-5’-tert butyl-benzo-5’-phenyl-benzo}15c4 (l2), 2,3,5,6-bis{3’-bromo-5’-tert butyl-benzo-5’-phenyl-benzo}18c5 (l3) have been synthesized and their alkaline metal compounds with naclo4∙h2o and kclo4  have been prepared. chemical formulas of all compounds have been characterized by usin...

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...

The title compound, C(31)H(34)N(2)O(9), is a product of the Michael addition of the cyclic secondary amine subunit of the (bis-pidino)aza-14-crown-4 ether to dimethyl acetyl-ene-dicarboxyl-ate. The mol-ecule comprises a tricyclic system containing the aza-14-crown-3 ether macrocycle and two six-membered piperidinone rings. The aza-14-crown-3-ether ring adopts a bowl conformation with a dihedral...

In the title complex, (NH3OH)2[PtCl6]·2C12H24O6, the Pt(IV) atom is coordinated by six chloride anions in a slightly distorted octa-hedral geometry. The Pt-Cl bond lengths are comparable to those reported for other hexa-chlorido-platinate(IV) species. The hy-droxy-ammonium groups act as linkers between the [PtCl6](2-) anion and the crown ether mol-ecules. The anion is linked to two hy-droxy-amm...

The title compound, [Fe(C(10)H(20)O(5))(H(2)O)(2)][Fe(2)(C(4)N(2)S(2))(4)]·2C(10)H(20)O(5), consists of an [Fe(II)(15-crown-5)(H(2)O)(2)](2+) cation, sandwiched between and O-H⋯O hydrogen bonded by two additional 15-crown-5 ether mol-ecules and two independent [Fe(III)(mnt)(2)](-) anions, where 15-crown-5 ether denotes 1,4,7,10,13-penta-oxacyclo-penta-decane and mnt denotes cis-1,2-dicyano-1,2-...