est, because the biologically effective chiral drug is either of enantiomers and the antipode is regarded as the impurity showing sometime high toxicity. Recently, the HPLC with chiral stationary phases (CSPs) has been extensively used to achieve the direct enantiomer separation. Crown ether, first introduced by Pedersen in 1967, was shown by Cram et al. to resolve enantiomers by the host-guest...

This paper describes novel host-guest systems comprising viologen cations (guests) and the derivatives of bis-para-phenylene-34-crown-10 (hosts) with anionic groups COO(-) or SO(3)(-). The structure of the resulting charge-compensated host-guest complexes, their association constants and their electrochemical behaviour have been studied. In the solid state, the viologen cations thread the negat...

Aspects of host-guest complexation are examined in the solvent-free environment of a mass spectrometer. A kinetic dissociation method is used to determine orders of relative ammonium and alkali metal cation binding affinities of an array of model hosts, such as crown ethers and their acyclic analogs. Sizeselective effects on binding are observed from these gas-phase experiments. The binding pro...

Extraction of microamounts of strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B-) in the presence of dibenzo-30-crown-10 (DB30C10, L) has been investigated. The equilibrium data have been explained assuming that the species HL+, SrL2+, SrHL3+ and SrHL3+2 are extracted into the organic phase. The values of extraction and stability constants of the cationic complexes in n...

Extraction of microamounts of cesium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B-) in the presence of 2,3-naphtho-15-crown-5 (N15C5, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, HL+2, CsL+ and CsL+2 are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene satu...

In the title compound, [CuBr(2)(H(2)O)(2)]·C(12)H(24)O(6)·2H(2)O, the Cu(II) atom, which is situated on an inversion centre and has a slightly distorted square-planar geometry, and the two coordinated water mol-ecules are linked to the 18-crown-6 macrocycles by O-H⋯O hydrogen bonds. The water mol-ecule of crystallization further links the metal complex and the crown ether macrocycles into a cha...

The present work is a theoretical investigation on supramolecular complexes of a fullerene crown ether (A and B isomers) with a derivative of π-extended tetrathiafulvalene (T). The geometry and the electronic structure of seven different conformers of the complex of dibenzo-18-crown-6 ether of fullero-N-methylpyrrolidine with a N-benzyl-N-(4-{[9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthrac...